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User’s Manual Model DRC-7/-70 Digital Cryogenic Thermometer Model DRC=?CMOC Digital Cryogenic Controller Obsolete Notice: This manual describes an obsolete Lake Shore product. This manual is a copy from our archives and may not exactly match your instrument. Lake Shore assumes no responsibility for this manual matching your exact hardware revision or operational procedures. Lake Shore is not responsible for any repairs made to the instrument based on information from this manual. Lake Shore Cryotronics, Inc. 575 McCorkle Blvd. Westerville, Ohio 43082-8888 USA E-Mail Addresses: [email protected] [email protected] Visit Our Website: www.lakeshore.com Fax: (614) 891-1392 Telephone: (614) 891-2243 Methods and apparatus disclosed and described herein have been developed solely on company funds of Lake Shore Cryotronics, Inc. No government or other contractual support or relationship whatsoever has existed which in any way affects or mitigates proprietary rights of Lake Shore Cryotronics, Inc. in these developments. Methods and apparatus disclosed herein may be subject to U.S.Patents existing or applied for. Lake Shore Cryotronics, Inc. reserves the right to add, improve, modify, or withdraw functions, design modifications, or products at any time without notice. Lake Shore shall not be liable for errors contained herein or for incidental or consequential damages in connection with furnishing, performance, or use of this material. Obsolete Manual 1975 Table of Contents Section I. General Information 1.1 Introduction 1.2 Description-General 1.3 Description-Specific 1.3.1 Model DRC-7 1.3.2 Model DRC-7C 1.3.3 Model DRC-70 1.3.4 Model DRC-70C 1.4 General Specifications 1.5 Accessory Equipment and Custom Options II. Installation 2.1 Introduction 2.2 Initial Inspection 2.3 Power and Grounding Requirements 2.4 Installation 2.5 Repackaging for Shipment III. Operating Instructions 3.1 Introduction 3.2 Controls, Indicators and Connectors 3.3 Initial Checks 3.4 Temperature Readout/Control 3.4.1 Model DRC-7 3.4.2 Model DRC-7C 3.4.3 Model DRC-70 3.4.4 Model DRC-70C 3.5 Customer Calibration 3.5.1 Model DRC-7 (A) Ten Microamp Sensor Current Adjustment (B) Calibration of Instrument Between 0-300 K 3.5.2 Models DRC-7C, DRC-70 and DRC-70C Page 1 1 1 2 2 2 2 3 5 6 6 6 8 8 9 9 12 12 12 13 14 16 17 17 17 18 Section IV. Theory of Operation 4.1 Introduction 4.2 General Description 4.3 Detailed Description 4.3.1 Power Supply and System Common 4 . 3 . 2 Two Wise Input 4 . 3 . 3 Four Wire Input 4 . 3 . 4 Linearizer 4 . 3 . 5 Comparators and Voltage References 4 . 3 . 6 Amplifier-Stage I lifier-Stage II ut Stage and Digital Display 4.4 Temperature Controller 4 . 4 . 1 Model DRC-7C 4 . 4 . 2 Model DRC-70C ce and Troubleshooting Introduction Test Equipment and Accessories 5.3 General Remarks 5.4 Operational Checks 5.5 Nomimal Operating Voltages and Gains 5.5.1 I n i t i a l Adjustments 5 . 5 . 2 Final Adjustments 5.6 Alignment of Controller Section 5.6.1 model DRC-7C 5.6.2 Model DRC-70C 5.7 Troubleshooting Panel Meter 5.8 Circuit Board Removal 5.9 Panel Meter Removal 5.10 Parts List, Printed Circuit Board Component Locator, and Schematic 5.1 5.2 VI. Appendixes Page 19 19 19 19 20 20 20 21 21 22 22 22 23 23 27 27 28 29 30 30 31 32 32 32 32 33 33 34 Table of I I l u s t r a t i o n s Reference Description Mode1 DRC-70 D i g i t a l Cryogenic Thermometer Sensor and Heater Cables Entry Number C o r r e l a t i o n Rear Panel Front Panel P i n Designation for Model DRC-7 BCD P i n Designation f o r Models DRC-7C, DRC-70, DRC-70C Figure 4 . 1 Timing Diagram for TS Greater Than TD Figure 4 . 2 Timing Diagram for TS Less Than TD Figure 5.1 C i r c u i t Schematic Diagram-Models DRC-7 and DRC-7C TEMPERATURE INDICATOR SECTION Figure 5.2 C i r c u i t Schematic Diagram-Models DRC-70 and DRC-70C TEMPERATURE INDICATOR SECTION Figure 5 . 3 C i r c u i t Schematic Diagram-Model DRC-7C TEMPERATURE CONTROLLER SECTION Figure 5.4 Circuit Schematic Diagram-Model DRC-70C TEMPERATURE CONTROLLER SECTION Figure 5.5 P r i n t e d C i r c u i t Board Components Locator Table 6.1 DRC-7 S e r i e s Standard S i l i c o n Diode Table 4-400 K Figure 1.1 Figure 2.1 Table 3.1 Figure 3.1 Figure 3.2 Table 3 . 2 Table 3.3 Page v 7 9 10 11 12 15 24 25 39 40 41 42 43 45 TY Lake Shore C r y o t r o n i c s , Inc. w a r r a n t s each i n s t r u ment o f i t s own manufacture t o be f r e e from d e f e c t s i n material and workmanship. O b l i g a t i o n s under t h i s Warranty s h a l l be l i m i t e d t o r e p l a c i n g , r e p a i r i n g o r g i v i n g c r e d i t f o r t h e purchase p r i c e , a t o u r opt i o n , o f any instrument r e t u r n e d , shipment p r e p a i d , t o o u r f a c t o r y f o r t h a t purpose w i t h i n ONE y e a r o f d e l i v e r y t o t h e o r i g i n a l p u r c h a s e r , provided p r i o r a u t h o r i z a t i o n f o r such r e t u r n has been g i v e n by an a u t h o r i z e d r e p r e s e n t a t i v e o f Lake Shore C r y o t r o n i c s , Inc. This Warranty s h a l l n o t apply t o any i n s t r u m e n t , which o u r i n s p e c t i o n s h a l l d i s c l o s e t o o u r s a t i s f a c t i o n , t o have become d e f e c t i v e o r unworkable due t o abuse, mishandling, misuse, a c c i d e n t , a l t e r a t i o n , negligence, improper i n s t a l l a t i o n , o r o t h e r causes beyond o u r c o n t r o l . This Warranty likewise s h a l l n o t apply t o any instrument o r component n o t manu f a c t u r e d by o t h e r s and i n c l u d e d i n Lake Shore C r y o t r o n i c s , Inc. equipment; t h e o r i g i n a l m a n u f a c t u r e r ' s warranty i s extended t o Lake Shore C r y o t r o n i c s , Inc. customers. Lake Shore Cryotronics reserves t h e r i g h t t o make changes i n design a t any time without i n c u r r i n g any o b l i g a t i o n t o i n s t a l l same on u n i t s p r e v i o u s l y purchased. THERE ARE NO WARRANTIES WHICH EXTEND BEYOND THE DESCRIPTION ON THE FACE HEREOF. THIS WARRANTY I S I N LIEU OF, AND EXCLUDES ANY AND ALL OTHER WARRANTIES OR REPRESENTATIONS, EXPRESSED, IMPLIED OR STATUTORY, I N CLUDING MERCHANTABILITY AND FITNESS, AS WELL AS ANY AND ALL OTHER OBLIGATIONS OR LIABILITIES OF LAKE SHORE CRYOTRONICS, I N C . , I N C L U D I N G , BUT NOT LIMITED TO, SPECIAL OR CONSEQUENTIAL DAMAGES. NO PERSON, FIRM OR CORPORATION IS AUTHORIZED TO ASSUME FOR LAKE SHORE CRYOTRONICS, I N C . ANY ADDITIONAL OBLIGATION OR LIABILITY NOT EXPRESSLY PROVIDED FOR HEREIN EXCEPT I N WRITING DULY EXECUTED BY AN OFFICER OF LAKE SHORE CRYOTRONICS, INC. SECTION I General Information 1.1 Introduction This s e c t i o n c o n t a i n s a d e s c r i p t i o n f o r t h e DRC-7 s e r i e s d i g i t a l temperature r e a d o u t / c o n t r o l l e r instruments which i n c l u d e t h e Models DRC-7, DRC-7C, DRC-70, and DRC-70C f o r use with t h e Model DT-500-DRC standard s i l i c o n diode s e n s o r . 1.2 Description-General The s e r i e s DRC-7 i s a completely s e l f - c o n t a i n e d u n i t providing t h e c a p a b i l i t y o f both d i r e c t d i g i t a l readout i n k e l v i n temperature u n i t s and temperature c o n t r o l (DRC-7C and DRC-70C) by d i r e c t d i g i t a l comparison t o t h e displayed temperature. The u s e f u l range o f o p e r a t i o n i s 1 t o 400 K u t i l i z i n g t h e s t a n d a r d DT-500-DRC sensor which has been pre-selected to provide uniform c h a r a c t e r i s t i c s . P r e - s e l e c t i o n allows t h e s e r i e s DRC-7 t o be used with s t a n d a r d s e n s o r s without adjustment of any kind. Since t h e standard s e n s o r s a r e completely interchangeable, t h e s e r i e s DRC-7 may be used t o read o u t any number o f s e n s o r s w i t h equal accuracy when s e l e c t e d through an a p p r o p r i a t e e x t e r n a l switch o r m u l t i p l e x e r . The s e r i e s DRC-7 u n i t s c o n t a i n an i n t e r n a l c o n s t a n t c u r r e n t source which i s p r e s e t a t t h e f a c t o r y f o r 10 microamps. As a s t a n d a r d f e a t u r e , a l l u n i t s a r e equipped w i t h a r e c o r d e r o u t p u t providing 0-4 v o l t s i n increments o f 10 m i l l i v o l t s p e r degree with a l i n e a r i t y e r r o r o f 0.5 K (DRC-7 and DRC-7C) and 0 . 3 K (DRC-70 and DRC-70C). Both t h e DRC-7C and DRC-70C r e a d o u t / c o n t r o l l e r u n i t s have an a d j u s t a b l e f i n e t u n i n g c o n t r o l f o r peak output power adjustment. The f i n e t u n i n g c o n t r o l i s continuously a d j u s t a b l e t o allow i n f i n i t e r e s o l u t i o n and minimizing o f t h e overshoot value. 1.3 Description-Specific The following provides a d e s c r i p t i o n f o r each s p e c i f i c instruments i n t h e DRC-7 s e r i e s d i g i t a l cryogenic thermometers and c o n t r o l l e r s . 1.3.1 Model DRC-7 The Model DRC-7 provides d i r e c t temperature readout i n k e l v i n temperature u n i t s with 1 degree r e s o l u t i o n . The e r r o r of l i n e a r i z a t i o n (conformity) is f a c t o r y set a t 0 . 5 degrees. 1.3.2 Model DRC-7C The Model DRC-7C combines t h e e l e c t r o n i c s contained i n t h e Model DRC-7 w i t h a time p r o p o r t i o n a l t h y r i s t o r temperature c o n t r o l l e r . The c o n t r o l p o r t i o n i s a c t u a t e d by an i n t e r n a l d i g i t a l comparison o f t h e BCD output t o a d i g i t a l thumbwheel s e t p o i n t switch. The BCD comparison s i g n a l provides an e r r o r value ( e q u i v a l e n t t o t h e temperature d e v i a t i o n ) t o a time p r o p o r t i o n a l t h y r i s t o r c o n t r o l c i r c u i t . The t h y r i s t o r c i r c u i t c o n t r o l s t h e ON time of t h e powered output a v a i l a b l e from a continuously a d j u s t a b l e v a r i a c with an a d j u s t a b l e power output o f 0 t o 50 watts. 1.3.3 Model DRC-70 The Model DRC-70, l i k e t h e DRC-7, provides temperature readout only. However, t h e r e s o l u t i o n has been improved t o 0.1 degree and t h e conformity e r r o r has been reduced t o 0 . 3 degrees. Both t h e Models DRC-7 and DRC-70 have a s t a n d a r d analog output, t o compliment t h e d i g i t a l display, p r o v i d i n g a 0-4 v o l t output w i t h a s l o p e o f 10 m i l l i v o l t s / d e g r e e with t h e i r respective linearity error. 1.3.4 Model DRC-70C The Model DRC-70C, as t h e DRC-7C, provides both temperature readout and c o n t r o l over t h e useable range of 1 t o 400 K. The DRC-70C combines t h e DRC-70 with a r e v o l u t i o n a r y new d i g i t a l p r o p o r t i o n a l t h y r i s t o r c o n t r o l u n i t having an i n t e r n a l f a c t o r y s e t bandwidth o f 0.5 k e l v i n . The d i g i t a l p r o p o r t i o n c o n t r o l provides f o r maximum agreement between t h e s e t p o i n t temperature and t h e a c t u a l temperature. A f i n e t u n i n g c o n t r o l i s provided on t h e f r o n t panel which allows t h e maximum peak v o l t a g e t o be a d j u s t e d between 0 and 50 v o l t s rms. The bandwidth is f i x e d about t h e s e t p o i n t value and i s equal t o ±0.5 K. Operation w i t h i n t h e bandwidth zone allows t h e c o n t r o l l e r t o work i n a p r o p o r t i o n a l mode. The p r o p o r t i o n a l mode o p e r a t i o n i s d e t e c t a b l e by a p u l s a t i n g or b l i n k i n g h e a t e r power ON l i g h t . Operation below t h e p r o p o r t i o n a l zone allows t h e c o n t r o l l e r to work i n a continuously ON condition. 1.4 General S p e c i f i c a t i o n s The following s p e c i f i c a t i o n s f o r t h e DRC-7 s e r i e s a r e a p p l i c a b l e when used w i t h t h e s t a n d a r d DT-500-DRC temperature s e n s o r . General : Temperature Range 1 t o 400 K Sensing Material S i 1icon (Mode 1 DT- 500-DRC) Sensor E x c i t a t i o n 10 microamps Sensor Current Regulation ±. 1% Sensor Input Connection 2 , 3 , o r 4 wire constant c u r r e n t I n p u t Resistance Greater than 100 megohms Is o l a t i on 300V Operating Environment 10-45°C Normal Mode Rejection 50 db min. a t 60 Hz and up Common Mode Reject i o n 120 db a t 60 Hz and above Power Requirements 115 o r 230* VAC ±10%, 50/60 Hz Dimensions 8.9 cm (3.5") high x 20.3 cm (8") wide x 30.5 cm (12") deep VA1,3, 60 VA2,4 Power Consumption 15 C i r c u i t Design Solid S t a t e Electronics Weight 3.6 Kg (8 pounds)1,3, 5.4 Kg (12 pounds)2,4 *For 230 VAC, add (-K) t o model number; i . e . DRC-70-K 1-Model DRC-7 only 2-Model DRC-7C only 3-Model DRC-70 only 4-Model DRC-70C only Temperature Readout: Res o lu t i on : Digital Analog Conformity t o LSCI Standard DRC-7 S i l i c o n Diode Table 1 k e l v i n 1 , 2 , 0.1 k e l v i n 3,4 B e t t e r than 0.1 k l v i n ( a l l u n i t s ) 0.5 K (4-400 K) 1,2 0.3 K (4-400 K)3,4 Maximum Sensor Power D i s s i p a t i o n 25 microwatts a t 4 . 2 K Maximum D i g i t i z i n g Error (8 hours a t 25°C) 0.5 K Temperature Co e f f i c ient Error 0.06 Repeat a b i li t y 1 k e l v i n 1 , 2 , 0.1 k e l v i n 3,4 outputs : Analog Digital (optional] K/°C 10 mV/K at 1 K o u t p u t impedance. Tracking t o d i g i t a l d i s p l a y of 0.3 K TTL compatible (non-i s o l a t e d ) Display 3 d i g i t s , 1 4 mm (0.55") 7 segment non -b l i n k i n g high, Response Time 2 seconds t o r a t e d accuracy Temperature Control : S e t Point D i g i t a l thumbwheel s e l e c t i o n d i r e c t l y i n k e l v i n temperature units Con t r o l lab i l it y 0.5 K 2 , 0.3 K with a p r o p e r l y designed system Repeatability 1 kelvin', S e tt ab i lit y 1 k e l v i n 2 , 0.1 k e l v i n 4 Heater Output Standard 0-50 watts, 0-1 A, 0-50 VAC Control Mode Time p r o p o r t i o n a l t h y r i s t o r with contin ously adjustable variac output Isolated d i g i t a l proportional with continuo s l y a d j u s t a b l e v a r i a c output 4 0.1 K4 2 4 1.5 Accessory Equipment and Custom Options Available The following accessory equipment and custom options are available from the factory. SECTION II I n s t al la t i on 2.1 Introduction This s e c t i o n c o n t a i n s information and i n s t r u c t i o n s necessary for t h e i n s t a l l a t i o n and s h i p p i n g o f t h e s e r i e s DRC-7 D i g i t a l Readout/Controller. Included a r e i n s p e c t i o n i n s t r u c t i o n s , power and grounding requirements, i n s t a l l a t i o n information, and i n s t r u c t i o n s f o r repackaging f o r shipment. 2.2 I n i t i a l Inspection This instrument was e l e c t r o n i c a l l y and mechanically inspected p r i o r t o shipment. I t should be f r e e from mechanical damages and i n p e r f e c t working o r d e r upon r e c e i p t . To confirm t h i s , t h e instrument should be i n s p e c t e d v i s u a l l y f o r obvious damage upon r e c e i p t and t e s t e d e l e c t r o n i c a l l y by use t o d e t e c t concealed damage. A l l p a r t s should be i n v e n t o r i e d b e f o r e d i s c a r d i n g any s h i p p i n g m a t e r i a l . I f t h e r e i s damage t o t h e instrument i n t r a n s i t , be s u r e t o f i l e a p p r o p r i a t e claims w i t h t h e c a r r i e r , and/or i n s u r a n c e company. Please a d v i s e t h e company o f such f i l i n g s . I n c a s e of p a r t s s h o r t a g e s , p l e a s e a d v i s e company. The s t a n d a r d Lake Shore Cryotronics warranty i s given on page ii. 2.3 Power and Grounding Requirements To p r o t e c t o p e r a t i n g personnel, t h e National E l e c t r i c a l Manufacturers' Association (NEMA) recommends and some l o c a l codes r e q u i r e instruments t o be grounded. This instrument i s equipped with a t h r e e conductor power c a b l e which, when plugged i n t o an a p p r o p r i a t e r e c e p t a c l e , grounds t h e instrument. The s t a n d a r d u n i t i s s e t f o r 115 VAC ±10%, 50/60 H e r t z o p e r a t i o n w i t h t h e designated (-K) u n i t s s e t for 230 VAC ±10, 50/60 Hertz. The s t a n d a r d 115 VAC u n i t may b e converted t o 230 VAC by r e q u e s t i n g t h e conversion procedure from t h e company. 2.4 Installation The recommended c a b l e diagrams f o r t h e s e n s o r diode and h e a t e r element a r e given i n Fig. 2.1 ( a ) . The use o f a f o u r wire diode connection is h i g h l y recommended t o avoid i n t r o d u c i n g lead I R drops i n t h e v o l t a g e s e n s i n g p a i r . The i n d i c a t e d s h i e l d i n g connections a r e t h e recommended s t a n d a r d p r a c t i c e t o avoid ground loops. For l e s s c r i t i c a l a p p l i c a t i o n s , t h e wiring scheme i n F i g . 2 . 1 (b) and (c) may be used. The h e a t i n g element should be f l o a t e d t o preclude t h e p o s s i b i l i t y o f any o f t h e h e a t e r c u r r e n t b e i n g conducted i n t o t h e diode sensor. E l e c t r i c a l feedback, i n a d d i t i o n t o t h e d e s i r e d thermal feedback, may cause o s c i l l a t i o n s and c e r t a i n l y erroneous temperature readings. 2.5 Repackaging f o r Shipment Before r e t u r n i n g an instrument t o t h e f a c t o r y f o r r e p a i r , p l e a s e d i s c u s s t h e malfunction w i t h a f a c t o r y r e p r e s e n t a t i v e . He may be a b l e t o suggest s e v e r a l f i e l d tests which w i l l p r e c l u d e r e t u r n i n g a s a t i s f a c t o r y instrument t o t h e f a c t o r y when t h e malfunction i s elsewhere. If it i s i n d i c a t e d t h a t t h e f a u l t i s i n t h e instrument a f t e r t h e s e t e s t s , t h e r e p r e s e n t a t i v e w i l l send s h i p p i n g i n s t r u c t i o n s and l a b e l s f o r r e t u r n i n g i t . When r e t u r n i n g an instrument, p l e a s e a t t a c h a t a g s e c u r e l y t o t h e instrument i t s e l f (not on t h e s h i p p i n g c a r t o n ) c l e a r l y s t a t i n g : (1) Owner and address (2) Instrument Model and S e r i a l Number (3) Malfunction symptoms (4) Description o f e x t e r n a l connections and c r y o s t a t s . I f t h e o r i g i n a l c a r t o n i s a v a i l a b l e , repack t h e instrument i n a p l a s t i c bag, p l a c e i n c a r t o n using o r i g i n a l styrafoam popcorn t o p r o t e c t p r o t r u d i n g c o n t r o l s , and c l o s e c a r t o n . Seal l i d w i t h paper or nylon t a p e . A f f i x mailing l a b e l s and “FRAGILE" warnings. I f t h e o r i g i n a l c a r t o n i s n o t a v a i l a b l e , wrap t h e instrument i n p r o t e c t i v e p l a s t i c wrapping m a t e r i a l b e f o r e p l a c i n g i n an i n n e r c o n t a i n e r . P l a c e shock absorbing material around a l l s i d e s of t h e instrument t o prevent damage eo p r o t r u d i n g c o n t r o l s . Place t h e i n n e r c o n t a i n e r i n a second heavy c a r t o n and s e a l with t a p e . Affix mailing l a b e l s and "FRAGILE" warnings. SECTION III Operating I n s t r u c t i o n s Introduction 3.1 This s e c t i o n c o n t a i n s a d e s c r i p t i o n o f t h e o p e r a t i n g c o n t r o l s and t h e i r adjustment under normal o p e r a t i n g c o n d i t i o n s . These i n s t r u c t i o n s a r e p r e d i c a t e d upon t h e instrument having been i n s t a l l e d as o u t l i n e d i n S e c t i o n II. The diode p o l a r i t y as shown i n Fig. 2 . 1 (a) i n p a r t i c u l a r must be c o r r e c t . C o n t r o l s , I n d i c a t o r s and Connectors 3.2 The o p e r a t i n g c o n t r o l s , i n d i c a t o r s and connectors on t h e i n s t r u m e n t ' s f r o n t and r e a r p a n e l s a r e shown i n Figures 3.1 and 3.2. The numbers with l e a d e r s t o v a r i o u s c o n t r o l s i n t h e f i g u r e s a r e keyed t o t h e e n t r i e s i n Table 3.1. Table 3.1 NO. KEY - Entry Number C o r r e l a t i o n NAME FUNCTION 1 Heater Heater element t e r m i n a l s 2 Analog (Hi 3 Input Sensor i n p u t l e a d t e r m i n a l s ( p l u s I , p l u s V, minus V, and minus I ) 4 NO LABEL A.C. 5 NO LABEL D i g i t a l temperature d i s p l a y l o c a t e d behind f i l t e r panel. Maximum range 1-400 K. 6 NO LABEL D i g i t a l s e t p o i n t switch. S e l e c t s d e s i r e d temperature t o be c o n t r o l l e d t o d i r e c t l y i n k e l v i n u n i t s . Adjustable from 2 t o 399 K. & Lo) Recorder output l i n e cord NO. KEY NAME FUNCTION 7 NO LABEL Fine t u n i n g power c o n t r o l . Adjusts t h e maximum power a v a i l a b l e from 0-50 VRMS. I n f i n i t e r e s o l u t i o n through t h e use of a v a r i a c c o n t r o l . 8 PWR A.C. 9 NO LABEL Heater ON l i g h t i n d i c a t e s power i s app 1i e d t o h e a t e r load BCD BCD output ( o p t i o n a l ) 10 3.3 l i n e switch (ON/OFF) I n i t i a l Checks I n i t i a l checks, c a l i b r a t i o n checks, and s e r v i c i n g procedures are described i n S e c t i o n V, Maintenance. 3.4 Temperature Readout/Control 3.4.1 Model DRC-7 The d i g i t a l panel meter has p r o v i s i o n s t o accept a connector a t t h e r e a r o f t h e case. A connector package i s s u p p l i e d which c o n s i s t s of a connector ELCO No. 00-6007-030-980-002 and two screws No. 4-40 thd by ½ inch long binding head. Table 3.2 provides t h e necessary p i n d e s i g n a t i o n f o r i n p u t and o u t p u t signals. Table 3 . 2 PIN NO. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. - Pin Designation f o r Model DRC-7 FUNCTION +4.8 v o l t s Analog (+) P r i n t Command Polarity BCD 8 BCD 2 BCD 80 BCD 20 Sensor Input (+) Analog (-) , S i g n a l Ground P I N NO. FUNCTION A. B. C. D. E. F. H. J. K. +9 v o l t s Current Test (+) Overrange Hold BCD 1 BCD 4 BCD 10 BCD 40 BCD 100 L. N/C B I N NO. 11. 1 2. 13. 14. 15 . FUNCTION BCD 400 BCD 200 Current Test (-) Sensor Input (-) 115/230 VAC Line 1 P I N NO. M. N. P. R. S. FUNCTION T r i p Point D i g i t a l Gnd, BCD Gnd N/C Shield 115/230 VAC Line 2 The s e n s o r i s connected t o t h e instrument v i a p i n s #9 and #14, The i n t e r n a l c u r r e n t source can be checked by p l a c i n g a 100 K ohm ±.01% r e s i s t o r between p i n s 13 and B and measuring t h e v o l t a g e drop with a v o l t m e t e r having an accuracy of 0.01% error. For t h o s e u n i t s having t h e o p t i o n a l BCD output, a binary-codeddecimal (BCD) i s provided as l i s t e d i n Table 3.2. The decade c o u n t e r s provide a 1-2-4-8 code u s i n g p o s i t i v e l o g i c w i t h standard TTL l e v e l s of 0 . 4 v o l t s and 2 . 4 v o l t s f o r t h e 0 and l state, r e s p e c t i v e l y . The d r i v e i s s u f f i c i e n t t o s i n k t w o standard loads, 3.2 mA, i n t h e low state. For a d d i t i o n a l usage, a switch o r TTL m i c r o c i r c u i t connected t o t h e h o l d terminal (Pin D) can be used t o keep t h e v o l t a g e level low and defeat the synchronizing signal applied to the synchronizing divider. This will prevent the generation of a r e s e t pulse. 3.4.2 Model DRC-7C The s e n s o r and h e a t e r should be i n s t a l l e d following t h e suggestions l i s t e d i n t h e " I n s t a l l a t i o n and Application Notes f o r Cryogenic Sensors” brochure i n S e c t i o n V I . Connect t h e s e n s o r and h e a t e r t o t h e instrument following t h e diagrams i n Fig. 2.1. Rotate t h e f i n e tuning power c o n t r o l (Key No. 7) f u l l c o u n t e r clockwise t o minimum power output. Adjust t h e d i g i t a l thumbwheel switch (Key No. 6) t o 001. Turn t h e power switch (Key No. 8) t o ON and observe t h a t t h e d i s p l a y (Key No. 5) shows t h e proper temperature r e l a t i v e t o t h e sample temperature. I f t h e d i s p l a y r e a d s -1800, 1090, o r blanks, the diode is connected backwards. The h e a t e r ON l i g h t (Key No. 9) should be o f f . Adjust t h e set p o i n t (Key No. 6) t o one degree below t h e value b e i n g d i s p l a y e d (Key NO. 5) and observe t h a t t h e h e a t e r power l i g h t (Key No. 9) remains o f f . Advance t h e set p o i n t 2 K and observe t h a t t h e h e a t e r power l i g h t t u r n s ON. Return t h e set p o i n t t o i t s o r i g i n a l v a l u e and check t h a t t h e h e a t e r power l i g h t s h u t s OFF. I f l i g h t does n o t s h u t o f f , check to see i f d i s p l a y i s i n d i c a t i n g a d i f f e r e n t temperature. The h e a t e r power l i g h t w i l l remain ON as long as t h e set p o i n t is less t h a n t h e d i s p l a y by a t least 1 K . I n c r e a s e t h e set p o i n t switch u n t i l t h e d e s i r e d value i s s e t . I f t h e temperature set p o i n t i s larger than t h e temperature being displayed, t h e h e a t e r ON l i g h t w i l l i l l u m i n a t e i n d i c a t i n g power is being a p p l i e d t o t h e h e a t e r . Observe t h e d i s p l a y and if t h e temperature being displayed does n o t show s i g n s o f h e a t i n g , then i n c r e a s e t h e maximum power o u t by r o t a t i n g , clockwise, t h e f i n e t u n i n g c o n t r o l knob (Key No. 7 ) . The knob should be r o t a t e d i n ¼ t u r n increments u n t i l t h e p r o p e r rate o f h e a t i n g is observed on t h e temperature d i s p l a y . I f t h e i n c r e a s e i n temperature is slow o r t h e temperature does n o t i n c r e a s e , (and i s s t i l l below t h e temperature set p o i n t ) , r o t a t e t h e f i n e t u n i n g knob a n o t h e r ¼ t u r n . Repeat above procedure u n t i l t h e d e s i r e d rate o r temperature i s achieved. When t h e readout is equal t o o r greater than t h e temperature s e t p o i n t , t h e heater ON l i g h t will switch OFF. The maximum c o n t r o l l a b i l i t y w i l l be achieved with t h e minimum v a l u e of amplitude p u l s e h e i g h t a p p l i e d t o t h e h e a t e r ( c o n t r o l l e d by t h e f i n e t u n i n g knob (Key No. 7 ) . This c o n d i t i o n can be d e t e c t e d by observing a continuous switching between ON and OFF of t h e h e a t e r ON l i g h t . 3.4.3 Model DRC-70 The s e n s o r should be connected t o both t h e sample area and instrument following t h e suggestions noted i n S e c t i o n 3.4.2. The s e n s o r and readout d i s p l a y should follow Table 6.1 which i l l u s t r a t e s t y p i c a l values expected of t h e s t a n d a r d DT-500-DRC s e n s o r s . If t h e instrument o r s e n s o r does n o t a g r e e with values l i s t e d i n t h e t a b l e , c o n s u l t s e c t i o n s on i n s t a l l a t i o n and/or s e c t i o n on t r o u b l e s h o o t i n g t o determine cause and c u r e o f malfunction. For t h o s e u n i t s equipped with BGD o u t p u t , t h e following Table 3 . 3 i l l u s t r a t e s t h e f u n c t i o n of each p i n d e s i g n a t i o n . Table 3.3 - BCD Pin Designation for Models DRC-7C, DRC-70, and DRC-70C PIN NO. FUNCTION 1 N/ A 2 N/A 3 Print command 4 Po larity 5 BCD 8 6 BCD 2 7 BCD 80 8 BCD 20 9 BCD 800 10 N/A 11 BCD 400 12 BCD 200 13 N/A 14 BCD 1000 15 Hold 16 BCD 1 17 BCD 4 18 BCD 10 19 BCD 40 20 BCD 100 21 Digital GND, BCD, GND 22 BCD 2000 23 N/A 24 Overload 25 Shift All terminations for above signals are located at t h e BCD connector (Key No. 10) type 117-10250 by Amphenol. 3.4.4 Model DRC-70C Connect t h e s e n s o r following t h e procedure o u t l i n e d i n Section 3.4.2. Before applying power, t h e f i n e t u n i n g c o n t r o l (Key No. 7) should be r o t a t e d f u l l counterclockwise to minimum power output and t h e set p o i n t switch (Key No. 6) t o 002.0 K. Note! If 000.0 K i s set i n t h e thumbwheel switch, t h e u n i t w i l l apply f u l l power t o t h e h e a t e r . Observe t h e temperature d i s p l a y (Key No. 5) and i f it i s greater than t h e set p o i n t by 0.5 K (Key No. 6 ) , t h e h e a t e r ON l i g h t (Key No. 9) should b e o f f i l l u s t r a t i n g zero power b e i n g a p p l i e d t o h e a t e r load. Adjust t h e set p o i n t t o a v a l u e equal t o 0.5 K less t h a n being displayed and observe t h a t t h e power ON l i g h t j u s t begins i l l u m i n a t e . Adjust i n 0.1 K increments, t h e s e t point, towards being displayed and observe t h e power ON l i g h t begins t o appear f r e q u e n t l y . When t h e set p o i n t v a l u e e q u a l s t h e d i s p l a y value, ON l i g h t should be on 50% of t h e time. Note! This test should performed with a displayed v a l u e less than 150 K. t h e value to t h e value more t h e power be Continue t o i n c r e a s e set p o i n t i n 0.1 K increments and note t h a t t h e power ON l i g h t continues t o i n c r e a s e i n frequency. With t h e set p o i n t equal to 0.5 K plus the value on display, the power ON l i g h t will be on continuously (100% o f t h e time) . I f t h e above observances are met, t h e u n i t i s f u n c t i o n i n g p r o p e r l y . If not, see s e c t i o n s on i n s t a l l a t i o n and s e c t i o n on t r o u b l e s h o o t i n g f o r c o r r e c t i n g m a l f u n c t i o n With t h e u n i t f u n c t i o n i n g p r o p e r l y , a d j u s t set p o i n t switch to t h e d e s i r e d temperature value. I n c r e a s e t h e maximum output power by r o t a t i n g t h e f i n e t u n i n g c o n t r o l (Key No. 7) ¼ t u r n and observe t h e rate o f h e a t i n g i n d i c a t e d by t h e readout d i s p l a y ' s r a t e of change. If t h e i n c r e a s e i n temperature is slow or t h e temperature does n o t i n c r e a s e , (and is s t i l l below t h e temperr o t a t e t h e f i n e t u n i n g knob another & t u r n . Repeat t h e a t u r e set p o i n t ) , above procedure until t h e d e s i r e d rate of i n c r e a s e o r t h e set temperature i s achieved, When t h e readout d i s p l a y is w i t h i n 0.5 K of t h e temperature set p o i n t , t h e h e a t e r ON l i g h t (Key No. 9) w i l l begin t o b l i n k p r o p o r t i o n a l l y to t h e d i f f e r e n c e between t h e set point temperature and t h e d i s p l a y temperature. I f t h e overshoot d r i v e s t h e temperature 0.5 K beyond t h e set p o i n t , t h e h e a t e r ON l i g h t w i l l switch o f f . The maximum c o n t r o l l a b i l i t y w i l l be achieved with minimum v a l u e of amplitude p u l s e h e i g h t a p p l i e d t o t h e h e a t e r ( c o n t r o l l e d by t h e f i n e t u n i n g knob - Key No. 7 ) . This c o n d i t i o n is d e t e c t e d by observing a 50% p r o p o r t i o n a l duty c y c l e switching between ON and OFF of t h e h e a t e r ON Bight . Customer C a l i b r a t i o n 3.5 The procedure o u t l i n e d below i s a p p l i c a b l e to Table 6.1 f o r a l i g n i n g a l l series DRC-7 instruments. 3.5.1 Model DRC-7* (A) Ten Microamp Sensor Current Adjustment (1) Remove t h e f r o n t panel cover on t h e meter. (2) Turn t h e power ON to t h e instrument and allow about BO minutes warm up. (3) Connect a voltmeter with a 0.01% accuracy and a 100 megohm minimum r e s i s t a n c e between p i n s B and 13, t h e p o s i t i v e t e r m i n a l o f t h e voltmeter should be connected t o p i n B. Connect a 10 uF c a p a c i t o r across p i n s B and 13 i f t h e connector leads are long. (4) Adjust t h e potentiometer marked “1”, l o c a t e d a t t h e back of t h e instrument u n t i l t h e v o l t m e t e r reads 100.0 m i l l i v o l t s . (B) Calibration of t h e Instrument Between 0-300 K (1) Connect a v o l t a g e standard, such as EDC Model MV-100N, to t h e probe i n p u t t e r m i n a l s and set t h e v a l u e of 2.81586 v o l t s on t h e v o l t a g e standard. *Note! (2) S e t t h e ZERO a d j u s t potentiometer u n t i l t h e meter d i s p l a y s 000. The ZERO potentiometer is l o c a t e d on t h e f r o n t p a n e l , a t t h e r i g h t hand s i d e of d i s p l a y , (3) S e t t h e v o l t a g e s t a n d a r d t o t h e value of 0.37721 v o l t s and a d j u s t t h e SPAN potentiometer u n t i l t h e meter d i s p l a y s 300. The SPAN potentiometer i s l o c a t e d to t h e l e f t of t h e d i s p l a y . (4) a i s p 1ayed . (5) Set the v o l t a g e s t a n d a r d t o t h e value of 1.09471 v o l t s and a d j u s t t h e potentiometer l a b e l e d "7" until t h e meter d i s p l a y s 035. This potentiometer i s l o c a t e d at t h e back of t h e meter. (6) Repeat above s t e p s , if necessary. Repeat s t e p s 1 through 3 u n t i l t h e r e s p e c t i v e readings are For DRC-7 u n i t s having a s e r i a l i z e d number g r e a t e r than 2000, use c a l i b r a t i o n procedure under S e c t i o n 3.5.2. 3.5.2 Models DRC-7C, DRC-70, and DRC-70C (1) Connect t h e i n p u t terminals t o a v o l t a g e s t a n d a r d such as EDN Model MV-100N o r e q u i v a l e n t and a voltmeter ( i n p u t ±199.99 mV, r e s o l u t i o n 10 uV, ±0.05% accuracy and an i n p u t impedance of not less than 1000 megohms) a c r o s s resistor R80. The p o s i t i v e terminal of t h e voltmeter should be connected t o t h e t e s t p o i n t 1 and t h e n e g a t i v e t e r m i n a l t o t e s t point 2 . (2) Turn t h e power on and allow approximately 60 minutes warm up time . (3) Adjust p o t e n t i o m e t e r R79 u n t i l t h e v o l t m e t e r reads 100.0 mV. (4) S e t t h e v o l t a g e s t a n d a r d t o 1.9755 v o l t s . Adjust t h e ZERO potentiometer R34 u n t i l t h e panel meter reads 013.1 (013 f o r Model BRC-7C) . (5) S e t the voltage s t a n d a r d t o 1.1283 v o l t s . Adjust potentiometer R19 t o a value of 028.0 on t h e panel meter d i s p l a y . (6) S e t the voltage standard to 0.9811 volts and adjust; p o t e n t i o m e t e r R26 t o a value of 077.3 (077 for Model DRC-7C) on t h e panel meter d i s p l a y . (7) S e t t h e v o l t a g e s t a n d a r d t o 0.099 v o l t s and a d j u s t potentiometer l a b e l e d “FS” (R33) t o a value of 395.2 (395 for Model DRC-7C) on t h e panel meter. (8) Repeat above s t e p s , if necessary, SECTION I V Theory o f Operation 4.1 Introduction T h i s s e c t i o n c o n t a i n s t h e t h e o r y of o p e r a t i o n of t h e series DRC-7 D i g i t a l Readout/Controller t o a i d t h e system engineer i n designing a s t a b l e thermal system. Refer t o Figures 4.1, 4.2, 5.1, 5.2, 5.3, 5.4, 5.5 as an a i d i n t h e following d i s c u s s i o n . 4.2 General Description "he diode s e n s o r (Model DT-500-DRC) is e x c i t e d by an a d j u s t a b l e (Rag) c o n s t a n t c u r r e n t source and forms t h e feedback element o f t h e i n p u t a m p l i f i e r (22). The output o f t h i s a m p l i f i e r i s a v o l t a g e r e f e r r e d t o t h e system common (TP #10) and is p r o p o r t i o n a l t o t h e v o l t a g e o u t p u t of t h e sensor. The amplifier output voltage is compared with a predetermined v o l t a g e r e f e r e n c e corresponding t o t h e v a r i o u s l i n e a r i z e r segment break p o i n t s from t h e s t a n d a r d DRC-7 v o l t a g e versus temperature t a b l e . The a t t e n u a t e d o u t p u t o f t h e i n p u t amplifier is fed i n t o two s t a g e s o f a m p l i f i e r s (23 and Z5) whose gain is v a r i a b l e as a f u n c t i o n of t h e s e n s o r temperature, The gain changing networks are switched by means o f analog switches set t o c l o s e when t h e v o l t a g e output o f t h e s e n s o r a m p l i f i e r (22) i s equal t o t h e predetermined v o l t a g e r e f e r e n c e corresponding t o each break p o i n t o f t h e DRC-7 s t a n d a r d t a b l e . The v o l t a g e o u t p u t o f t h e l i n e a r i z e r i s a l i n e a r f u n c t i o n o f t h e s e n s o r temperature. This output i s converted t o a l i n e a r i z e d output of 10 mV/K and t h e d i g i t a l voltmeter r e a d s and d i s p l a y s t h i s o u t p u t . 4.3 Detailed D e s c r i p t i o n A d e t a i l e d d e s c r i p t i o n o f t h e v o l t a g e temperature conversion i s o u t l i n e d below . 4.3.1 Power Supply and System Common The output of transformer (T1) i s r e c t i f i e d and f i l t e r e d t o 22 VDC by means o f a f u l l wave b r i d g e (CR1-4) and a c a p a c i t o r C24 f i l t e r . "he l i n e f i l t e r C19, C20, and C25 on t h e power l i n e bypasses t h e high frequency n o i s e s i g n a l i n t h e power lime. The f i l t e r e d , b u t unregulated, 22 VDC i s r e g u l a t e d t o 14 VDC by a p r e c i s i o n v o l t a g e r e g u l a t o r (Z24), The v o l t a g e s a t v a r i o u s p a r t s of t h e c i r c u i t are r e f e r r e d t o t h e "System Common" which i s t h e o u t p u t o f t h e a m p l i f i e r (27). The common i s l o c a t e d 7 VDC below t h e p o s i t i v e r e g u l a t e d v o l t a g e . This v o l t a g e can be a d j u s t e d t o w i t h i n ±0.001 v o l t s w i t h p o t e n t i o m e t e r R71. The a m p l i f i e r s , comparators, and t h e analog switches i n t h i s system are o p e r a t e d between V+ and V- (14 v o l t s ) and t h e networks f o r t h e b i a s and gain c o n t r o l s work between V+ and common. Therefore, t h e o u t p u t o f a l l a m p l i f i e r s i s r e f e r r e d t o t h e "System Common". 4.3.2 Two Wire Input This diode s e n s o r i s s u p p l i e d by a c o n s t a n t c u r r e n t of 10 microamperes which i s a d j u s t a b l e (R79) t o provide t h e c u r r e n t e x c i t a t i o n . The s e n s o r forms t h e feedback element o f t h e a m p l i f i e r (22). The o f f s e t a d j u s t p o t e n t i o m e t e r (R89) p r o v i d e s t h e e x a c t v o l t a g e r e q u i r e d by t h e l i n e a r i z e r . The two-wire i n p u t i s s u b j e c t t o v o l t a g e e r r o r s produced by t h e I R drops along t h e l e a d wires w i t h 10 microamps flowing. 4.3.3 Four Wire Input S i n c e t h e s e n s o r forms t h e feedback element o f a m p l i f i e r Z2, t h e l e a d r e s i s t a n c e w i l l have a n a p p r e c i a b l e e f f e c t on t h e accuracy as noted i n S e c t i o n 4 . 3 . 2 . This e f f e c t i s reduced by u t i l i z i n g a four-wire i n p u t as follows. The o u t p u t o f a m p l i f i e r Z2 i s connected t o t h e n e g a t i v e i n p u t of t h e u n i t y gain a m p l i f i e r Z11. The p o s i t i v e i n p u t o f a m p l i f i e r Z11 i s r e f e r r e d t o t h e cathode o f t h e s e n s o r through l e a d # 3 ( p i n #11). The v a r i a t i o n o f t h e o u t p u t o f a m p l i f i e r Z2 due t o t h e l e a d r e s i s t a n c e o f l e a d #1 ( p i n #9) and l e a d #2 (pin #10) i s equal and o p p o s i t e t o t h e v a r i a t i o n o f t h e v o l t a g e o f l e a d # 3 ( p i n #11). Due t o t h e e q u a l i t y , t h e y cancel a t t h e o u t p u t o f t h e a m p l i f i e r Z11 which p r o v i d e s t h e e x a c t v o l t a g e s (equal t o s e n s o r ) r e q u i r e d by t h e l i n e a r i z e r . For long l e a d r u n s , it i s suggested t h a t s h i e l d c a b l e s be used t o minimize n o i s e pickup. 4.3.4 Linearizer The s e r i e s DRC-7 u t i l i z e s s t r a i g h t l i n e segments o v e r t h e range o f 1 t o 400 k e l v i n with break p o i n t s a t 6 K , 1 4 K , 18 K , 23 K , 25 K , 27 K, 30 K , and 80 K. The s l o p e between 18 and 23 K i s t h e l a r g e s t (75.3 mV/K) and, hence, t h e gain o f t h e l i n e a r i z e r i s t h e lowest between t h e s e p o i n t s . S i m i l a r l y , t h e l i n e a r i z e r has i t s h i g h e s t gain between 30 and 80 K where t h e diode has t h e s m a l l e s t s l o p e of 2.66 mV/K. 4.3.5 Comparators and Voltage References The r e f e r e n c e v o l t a g e s a r e formed i n s t e p s o f ascending o r d e r corresponding t o t h e v o l t a g e output o f t h e i n p u t a m p l i f i e r a t t h e various break p o i n t s . A l a d d e r network connected between V+ and common provide these voltages . The r e f e r e n c e v o l t a g e s a r e compared with t h e r e s p e c t i v e output v o l t a g e s of t h e i n p u t a m p l i f i e r and analog switches SW4 through SW7 a r e c l o s e d when t h e a m p l i f i e r v o l t a g e i s equal t o t h e r e f e r e n c e v o l t a g e . The analog switches SW1, SW2, and SW3 a r e s e t t o open when t h e a m p l i f i e r v o l t a g e exceeds t h e r e f e r e n c e v o l t a g e . This occurs when t h e i n i t i a l gain o f t h e l i n e a r i z e r i s lower than t h e lowest gain which occurs between 18 and 23 K. Analog switch SW8 opens a t 80 K s i n c e t h e gain over t h e temperature range 80 t o 400 K i s lower than t h e gain between 30 and 80 K . Due t o t h e sharp i n c r e a s e i n gain between 27-30 K and 30-80 K , t h e analog switches should be closed e x a c t l y a t t h e a m p l i f i e r v o l t a g e c o r r e s ponding t o break p o i n t s 27 K and 30 K. The adjustments f o r t h e s e two break p o i n t s a r e accomplished with potentiometers R99 and R98, r e s p e c t i v e l y . The high s l o p e below 27 K guarantees t h a t t h e e r r o r r e s u l t i n g from t h e s e t p o i n t accuracy o f t h i s break p o i n t w i l l n o t have any s i g n i f i c a n t e f f e c t on t h e o v e r a l l accuracy. The s e t p o i n t accuracy a t t h e break p o i n t f o r 80 K is n o t very c r i t i c a l s i n c e t h e o v e r a l l gain between 80 and 400 K i s reduced only by 1/28th o f t h e maximum gain. 4.3.6 Amplifier - Stage I The c h a r a c t e r i s t i c s o f t h e Model DT-500-DRC (see s t a n d a r d t a b l e o f DRC-7) shows t h a t t h e r a t i o o f t h e h i g h e s t gain t o t h e lowest g a i n is 28. Therefore, t o o p e r a t e a m p l i f i e r Z3 w i t h i n i t s l i n e a r r e g i o n , it i s necessary t o a t t e n u a t e t h e s i g n a l o f t h e i n p u t a m p l i f i e r Z2 t o approximately 1/20 of i t s a c t u a l l e v e l . This s i g n a l is f e d i n t o t h e p o s i t i v e terminal of u n i t y gain a m p l i f i e r Z3 t o maintain t h e p r o p e r sign, with t h e n e g a t i v e i n p u t t e r m i n a l following t h e p o s i t i v e i n p u t t e r m i n a l and w i t h t h e d i f f e r e n c e being only t h e o f f s e t v o l t a g e o f t h e a m p l i f i e r . Therefore, when t h e comparator c l o s e s t h e analog switch, a r e f e r e n c e v o l t a g e equal t o t h e v o l t a g e at t h e n e g a t i v e terminal i s switched. A t t h e p o i n t o f switching, no c u r r e n t flows through Rswitch. For example, i f analog switch SW4 i s c l o s e d , t h e r e f e r e n c e v o l t a g e V12 i s a p p l i e d and i s e q u i v a l e n t t o t h e v o l t a g e a t break p o i n t 2 3 K. No c u r r e n t w i l l flow through R10 f o r break p o i n t 2 3 K p r o v i d i n g a gain o f Z3 e q u i v a l e n t t o t h e gain f o r segment 18 t o 23 K. As t h e i n p u t v o l t a g e i n c r e a s e s , c u r r e n t , p r o p o r t i o n a l t o t h e i n p u t v o l t a g e , flows through R10 and t h e g a i n o f a m p l i f i e r Z3 i s modified accordingly The gain network a t t h e n e g a t i v e i n p u t o f a m p l i f i e r Z3 is d i v i d e d i n t o 1 / 3 R and 2 / 3 R i n o r d e r t o keep t h e value o f R7 and R4, r e s p e c t i v e l y , w i t h i n 1.3 megohms. I t i s a l s o necessary t o keep t h e value o f R20 above 10 K ohms so t h a t t h e r e s i s t a n c e o f t h e analog switch w i l l be n e g l i g i b l e compared t o R20. A t break p o i n t s 27 K and 30 K , t h e value of (V18 and V19) and (V25 and V26) should be e x a c t l y equal t o t h e v o l t a g e a t t h e n e g a t i v e i n p u t t e r m i n a l o f Z3 through a d j u s t a b l e potentiometers R26 and R19. Since t h e gain between 4 and 6 K i s lower than t h a t between 6 and 1 4 K, r e s i s t o r R35 is switched a c r o s s R49 (feedback r e s i s t o r ) t o provide t h e lower gain r e q u i r e d . I n t h e temperature range 18 t o 2 3 K , a l l switches SW1 through SW7 a r e open t o provide t h e p r o p e r s l o p e and gain for conformity t o standard DRC-7 t a b l e . 4.3.7 Amplifier - Stage II Operation between 80 t o 400 K i s accomplished with t h e break p o i n t s e t f o r 80 K which t r i g g e r s t h e comparator t o o p e r a t e switch SW8 i n t o an open s t a t e . The comparator switches when t h e v o l t a g e a t t h e i n p u t t o Z5 exceeds 0.97405 v o l t s . With t h e gain change i n t h i s s t a g e only 1/28th o f t h e h i g h e s t gain, any e r r o r introduced by r e s i s t o r R22 and t h e v o l t a g e o f f s e t i n a m p l i f i e r Z5 w i l l be n e g l i g i b l e . 4.3.8 Output Stage and D i g i t a l Display The o u t p u t a m p l i f i e r Z5 provides t h e necessary o f f s e t and gain t o y i e l d an o v e r a l l output o f 4.000 v o l t s corresponding t o 400.0 k e l v i n with a l i n e a r response o f 10 mV/K as i n d i c a t e d by t h e d i g i t a l voltmeter (DVM) d i s p 1ay 4.4 Temperature Controller The f u n c t i o n o f t h e c o n t r o l l e r i s t o apply power t o t h e h e a t e r when t h e r e a d i n g on t h e d i g i t a l d i s p l a y i s below t h e value s e t by t h e d i g i t a l s e t p o i n t c o n t r o l switch. The f u l l power condition of t h e h e a t e r i s i n d i c a t e d by a red l i g h t e m i t t i n g diode (LED), (Key No. 9 ) . The maximum ( f u l l power) h e a t e r v o l t a g e i s continuously a d j u s t a b l e ( v i a f i n e t u n i n g power c o n t r o l , Key No. 7) between 0 and 50 VAC and can supply a maximum output c u r r e n t o f 1 amp. 4.4.1 Model DRC-7C The following d e s c r i p t i o n o f t h e c o n t r o l l e r system r e f e r s t o Figures 4.1, 4 . 2 , and 5.3. Assume t h e temperature s e t p o i n t TS is g r e a t e r than t h e temperature d i s p l a y TD (Fig. 4.1), t h e n t h e BCD output o f t h e counters (214, Z15, and 216) i s below t h e BCD code generated by t h e thumbwheel switch s e t t i n g . A comparison i s attempted with Z10, Z18, Z19, and Z20. However, due t o t h e i n e q u a l i t y , a comparison cannot be made and a l o g i c 1 i s provided which l a t c h e s Z13 and f u l l power i s a p p l i e d t o t h e h e a t e r and t h e power ON l i g h t (Key No. 9) i s turned ON i n d i c a t i n g f u l l power f o r a f i x e d number o f timing c y c l e s determined by updating s i g n a l contained i n t h e d i g i t a l panel meter. Assume t h e temperature set p o i n t TS is less than t h e temperature d i s p l a y TD (Fig. 4 . 2 ) , then t h e BCD output o f t h e counters ( Z 1 4 ,Z15, and 216) i s g r e a t e r t h a n t h e BCD code generated by t h e thumbwheel switch s e t t i n g . A comparison i s made u t i l i z i n g comparators Z10, Z18, Z19, and Z20 r e s u l t i n g i n an equal o r greater than c o n d i t i o n which d r i v e s t h e comparator output t o a l o g i c s t a t e 0. This c o n d i t i o n i s l a t c h e d with Z13 and remains l a t c h e d u n t i l a r e s e t occurs. The l a t c h e d c o n d i t i o n w i l l occur f o r both TS<TD and TS = TD. To prevent f u l l power from being a p p l i e d d u r i n g t h e r e s e t c y c l e , t r a n s i s t o r s Q4 and Q5 are equipped w i t h RC networks (R123, C35 and R 1 3 1 , C30) f o r a s h o r t time delay. 4.4.2 Model DRC-70C The d i g i t a l p r o p o r t i o n a l c o n t r o l l e r with f i x e d bandwidth u t i l i z e s The d i g i t a l p r o p o r t i o n a l c i r c u i t samples t h e temperature d i s p l a y and temperature s e t p o i n t t o determine t h e magnitude o f d i f f e r e n c e and adds a p r o p o r t i o n a l l y g r e a t e r number o f signal p u l s e s t o t h e h e a t e r output c i r c u i t f o r s u c c e s s i v e l y l a r g e r d e v i a t i o n s between temperature d i s p l a y and temperature set p o i n t . a new concept f o r c o n t r o l . The c i r c u i t i s f a c t o r y a d j u s t e d (216) f o r a bandwidth of ±½ K about t h e temperature s e t p o i n t . The bandwidth c i r c u i t adds i t s o u t p u t t o t h e i n p u t from t h e BCD output of t h e temperature d i s p l a y allowing t h e comparators t o s e e an a r t i f i c i a l value o f real temperature. The bandwidth c i r c u i t adds t h e a r t i f i c i a l temperature u n i t s t o t h e counter (216) by way of a d d i t i o n a l counts, with each a d d i t i o n a l count e q u i v a l e n t t o 0.1 degree. The a r t i f i c i a l temperature i s c o n s t a n t l y a d j u s t i n g f o r changes between actual temperature and set p o i n t temperature t o a r r i v e a t a c o n t r o l l e d temperature approximately equal t o t h e d i s p l a y e d temperature. Assume t h e a r t i f i c i a l temperature (TA) is ½ K (5 counts) above t h e a c t u a l d i s p l a y temperature TD and t h a t t h e temperature set p o i n t TS is equal t o TD t h e n as i n S e c t i o n 4.4.1, t h e c o n t r o l c i r c u i t w i l l provide a l o g i c s t a t e 0 t o prevent power from being a p p l i e d except for a small amount o f r e s i d u a l power which i n c r e a s e s l i n e a r i t y from 0 K (0 power) t o 400 K (15%power). Assume t h e temperature s e t p o i n t (Ts) i s g r e a t e r than t h e temperature d i s p l a y TD. S i n c e t h e c o u n t e r c i r c u i t i s modified t o count 5 counts (½ K) above t h e d i s p l a y , t h e d i s p l a y w i l l a c t u a l l y be 5 counts (½ K) below t h e a r t i f i c i a l temperature TA. When t h e d i s p l a y is 5 counts below t h e temperature s e t p o i n t s e t t i n g , then t h e l a t c h c i r c u i t Z17 allows t h e bandwidth c o u n t e r (216) t o r e g i s t e r t h e number o f counts above t h e s e t point and transfer these t o comparison circuit Z10, Z18, Z19, and Z20. The comparison number is converted t o a p r o p o r t i o n a l v o l t a g e which d r i v e s a ramp g e n e r a t o r (222) t o p r o v i d e an a d j u s t a b l e time p e r i o d (R128) p r o p o r t i o n a l t o t h e count. The p r o p o r t i o n a l time p e r i o d d r i v e s t r a n s i s t o r s Q3 and Q4 t o provide power t o t h e h e a t e r . SECTION V Maintenance and Trouble Shooting 5.1 Introduction This s e c t i o n c o n t a i n s i n s t r u c t i o n s f o r maintaining and c a l i b r a t i n g t h e series DRC-7 instrument, nominal v o l t a g e values and g a i n s , c i r c u i t schematic diagrams, p r i n t e d c i r c u i t board component diagram, and p a r t s list. 5.2 Test Equipment and Accessories The following t e s t equipment i s r e q u i r e d t o perform t h e necessary ad j us tment s . a) Voltage Standard: E l e c t r o n i c Development Corporation, Model MV-100N o r equivalent b) Voltmeter #1: - Input ±9.999 v o l t s Resolution - 1 mV Accuracy - ±0.05% Reading, ±0.05% F.S. Input Impedance - Not l e s s than 100 megohms Voltmeter # 2 : Input - ±1.999 v o l t s Resolution - 1 mV Accuracy ±0.05% Reading, ±0.05% F.S. Input Impedance - Not l e s s than 100 megohms - Voltmeter # 3 : Input - ±199.9 mV Resolution 100 uV Accuracy - ±0.05% Reading, ±0.05% F.S. Input Impedance - Not less than 1000 megohms - Voltmeter #4: Input - ±199.99 mV Resolution - 10 uV Accuracy - ±0.05% Reading, ±0.05% F.S. Input Impedance Not less than 1000 megohms - A l l voltmeters should have t h e i r l e a d s with E-Z hook terminals. 5.3 General Remarks Upon i n i t i a l i n s t a l l a t i o n , t h e s i n g l e most probable cause o f system malfunction i s an improperly connected temperature s e n s i n g diode. I f t h e d i s p l a y blanks o r a n e g a t i v e temperature i s d i s p l a y e d , c a r e f u l l y examine t h e cable/diode assembly t o i n s u r e t h a t t h e diode p o l a r i t y i s c o r r e c t , t h a t t h e s e n s o r is connected t o t h e proper t e r m i n a l s , and t h a t t h e r e a r e good s o l d e r j o i n t s a t t h e i n t e r f a c e connection. Because of t h e h i g h l y r e l i a b l e s o l i d s t a t e design o f t h e r e a d o u t / c o n t r o l l e r , it i s most u n l i k e l y t h a t t h e r e a d o u t / c o n t r o l l e r w i l l be a source o f d i f f i c u l t y . For t h i s reason, it i s a d v i s a b l e t o examine o t h e r p o r t i o n s of t h e cryogenic system before t e s t i n g t h e r e a d o u t / c o n t r o l l e r proper. Some suggested checks a r e : (1) Open o r s h o r t e d s e n s o r and h e a t e r l e a d s , p a r t i c u l a r l y i n t h e v i c i n i t y of t h e sample h o l d e r i f it i s s u b j e c t t o f r e q u e n t disassembly. (2) Leakage p a t h s between h e a t e r and s e n s o r l e a d s g i v i n g r i s e t o e l e c t r i c a l feedback i n a d d i t i o n t o thermal feedback. (3) Poor thermal lagging o f s e n s o r i n p u t l e a d s normally r e s u l t s i n an i n d i c a t e d temperature s e v e r a l degrees h i g h e r than t h e a c t u a l temperature. (4) Extraneous r e s i s t a n c e i n t h e s e n s o r ' s v o l t a g e l e a d s which i n c r e a s e s t h e apparent s e n s o r ' s v o l t a g e p r o p o r t i o n a l t o t h e v o l t a g e drop ( I times R) a c r o s s extraneous l e a d r e s i s t a n c e . This normally manifests i t s e l f as an i n d i c a t e d temperature which i s lower then t h e a c t u a l temperature. (5) Premature l o s s o f cryogens due t o thermal s h o r t s i n dewar, i c e blocks i n l i n e s , sample h o l d e r immersed i n cryogen d i r e c t l y , sample h o l d e r i n vapor whose temperature i s above t h e c o n t r o l l e r s e t p o i n t temperature, e t c . (6) Excessive thermal p a t h phase l a g s w i l l cause t h e c o n t r o l loop t o be u n s t a b l e due t o large i n t e r n a l gain values. Physical s e p a r a t i o n between t h e diode and h e a t e r , p a r t i c u l a r l y by p a t h s o f small thermal c r o s s - s e c t i o n , should be avoided. I f it i s i n d i c a t e d t h a t t h e c o n t r o l l e r i s malfunctioning a f t e r performing t h e t e s t s t o be d e s c r i b e d below, it i s recommended t h a t t h e instrument be r e t u r n e d t o t h e f a c t o r y o r t o an authorized f a c t o r y r e p a i r r e p r e s e n t a t i v e f o r r e p a i r . The components used i n t h e instrument a r e c o s t l y and may be permanently damaged i f s u b j e c t e d t o i n a p p r o p r i a t e t e s t v o l t a g e s o r e x c e s s i v e s o l d e r i n g i r o n h e a t . Although premium m a t e r i a l s and techniques have been used t o f a b r i c a t e t h e instrument c i r c u i t board, t h e r e is always t h e r i s k o f l i f t i n g a connection pad o r cracking t h e board when unsoldering a component. 5.4 Operational Checks Replace t h e s e n s o r diode with a t e s t f i x t u r e c o n t a i n i n g a p r e c i s i o n r e s i s t o r o r r e s i s t a n c e decade box and a 100 ohm, 20 watt r e s i s t o r . The p r e c i s i o n r e s i s t o r r e p l a c e s t h e diode s e n s o r and t h e high wattage r e s i s t o r r e p l a c e s t h e c r y o s t a t h e a t e r . With 10 microamperes flowing through t h e t e s t r e s i s t o r , a 1 . 0 v o l t p o t e n t i a l should develop a c r o s s a 100 K ohm r e s i s t o r . This t e s t c o n d i t i o n should provide a temperature d i s p l a y of 70 K and a corresponding analog output value o f 0.70 V. A s a f u r t h e r check, an independent voltmeter e q u i v a l e n t t o Voltmeter #1 may be used t o monitor d i r e c t l y t h e v o l t a g e drop developed a c r o s s t h e t e s t r e s i s t o r . Comparison o f t h i s v o l t a g e t o t h e standard DRC-7 s i l i c o n diode t a b l e determines t h e temperature value expected as well as t h e accuracy o f t h e f a c t o r y a d j u s t e d i n t e r n a l c u r r e n t source. Adjust t h e temperature s e t p o i n t switch t o equal t h e temperature value displayed. With t h e set p o i n t switch equal t o o r less than t h e d i s p l a y , t h e power h e a t e r ON l i g h t w i l l illuminate i n d i c a t i n g t h e power being a p p l i e d t o t h e h e a t e r l o a d . With t h e s e t p o i n t value g r e a t e r than t h e d i s p l a y value, t h e c o n t r o l l e r ' s ON l i g h t should be o f f i n d i c a t i n g no power a p p l i e d t o t h e h e a t e r load. For o p e r a t i o n o f t h e Model DRC-70C, t h e ON w i l l n o t s h u t o f f u n t i l t h e d i s p l a y temperature is g r e a t e r than p o i n t temperature by 0.5 K. the set I f t h e instrument responds t o t h e tests o u t l i n e d above as i n d i c a t e d , e i t h e r t h e t r o u b l e l i e s elsewhere i n t h e system o r t h e malfunction i n t h e c o n t r o l l e r is of a s u b t l e n a t u r e . A s an a i d i n t r o u b l e s h o o t i n g i n t h e l a t t e r c a s e , t y p i c a l v o l t a g e s and gains a r e given i n Section 5.5. 5.5 Nominal Operating Voltages and Gains 5.5.1 I n i t i a l Adjustments Connect t h e v o l t a g e s t a n d a r d such as EDN-MV 100N as l i s t e d i n S e c t i o n 5.2 a c r o s s t h e i n p u t terminals (+ and - i n p u t v o l t a g e t e r m i n a l s ) and Voltmeter #4 a c r o s s R80 ( p o s i t i v e terminal t o t e s t p o i n t #1 and n e g a t i v e t e r m i n a l t o t e s t p o i n t #2). The adjustment procedure is divided i n t o s e v e r a l small s e c t i o n s . Care should b e taken not t o touch i n t e g r a t e d c i r c u i t s 4016 (Z6 and Z8) since any s t a t i c charge on t h e body might cause permanent damage t o t h e integrated circuits. Turn t h e "POWER ON" t o t h e instrument and allow one hour warmup time. Connect t h e p o s i t i v e l e a d o f Voltmeter #1 t o t e s t p o i n t #9 (R80) and t h e n e g a t i v e l e a d t o t e s t p o i n t #10 (R27). Adjust potentiometer R71 u n t i l t h e DVM reads 7.000 v o l t s (50.001 v o l t s ) . With Voltmeter #4 i n d i c a t i n g t h e v o l t a g e a c r o s s R80, a d j u s t R79 u n t i l a r e a d i n g o f 100.00 m i l l i v o l t s i s obtained. Connect t h e p o s i t i v e l e a d o f Voltmeter # 2 t o t e s t p o i n t # 3 (Z4-pin #14). Connect t h e n e g a t i v e l e a d of Voltmeter #2 t o t e s t p o i n t #10. S e t t h e v o l t a g e s t a n d a r d t o 1.6884 v o l t s and a d j u s t t h e potentiometer R82 u n t i l Voltmeter #2 i n d i c a t e s 0.977 v o l t s . Now connect t h e p o s i t i v e l e a d of Voltmeter # 2 t o t e s t p o i n t #4 (Z4-pin #1), r e t a i n i n g t h e n e g a t i v e l e a d a t t e s t p o i n t #10. Adjust R99 u n t i l t h e v o l t m e t e r i n d i c a t e s 1.527 v o l t s . Connect t h e p o s i t i v e l e a d o f Voltmeter #1 t o t e s t p o i n t #5 (Z4-pin # 3 ) , r e t a i n i n g t h e n e g a t i v e l e a d a t t e s t p o i n t #10. S e t t h e v o l t a g e s t a n d a r d t o 1.1390 v o l t s . Voltmeter #1 should i n d i c a t e p o s i t i v e s a t u r a t i o n v o l t a g e (approximately 6 volts). S e t t h e v o l t a g e s t a n d a r d t o 1.1395 v o l t s and observe t h e reading on Voltmeter #1 i s a n e g a t i v e s a t u r a t i o n v o l t a g e (approximately -6 v o l t s ) . If necessary, a d j u s t R99 u n t i l t h i s c o n d i t i o n i s achieved. This guarantees t h a t t h e comparator changes i t s s t a t e both above and below t h e s e t p o i n t . Connect t h e p o s i t i v e l e a d of Voltmeter #2 t o t e s t p o i n t #6 (Z7-pin #1) and a d j u s t R98 f o r an i n d i c a t i o n o f 1.559 v o l t s on v o l t m e t e r #2. Connect t h e p o s i t i v e lead o f Voltmeter #1 t o t e s t p o i n t #7 (Z4-pin #4) and s e t t h e v o l t a g e s t a n d a r d t o 1.1071 v o l t s . Voltmeter #1 should i n d i c a t e a p o s i t i v e s a t u r a t i o n v o l t a g e (approximately 6 v o l t s ) . S e t t h e v o l t a g e s t a n d a r d t o 1.1075 v o l t s and v e r i f y t h e Voltmeter #1 now i n d i c a t e s a n e g a t i v e s a t u r a t i o n v o l t a g e (approximately -6 v o l t s ) . Readjust R98 u n t i l t h e above c o n d i t i o n s are achieved. The comparator i s now set f o r proper switching l e v e l s . For s e t t i n g t h e a m p l i f i e r gain, a d j u s t t h e v o l t a g e s t a n d a r d t o 1.6884 v o l t s . Adjust R89 f o r a r e a d i n g of 46.5 m i l l i v o l t s as i n d i c a t e d on Voltmeter # 3 when connected between t e s t p o i n t #8 (R49) and t e s t p o i n t #10. 5.5.2 F i n a l Adjustments S e t t h e v o l t a g e s t a n d a r d t o 1.9755 v o l t s and a d j u s t t h e potentiometer l a b e l e d ZERO (on f r o n t p a n e l ) f o r a r e a d i n g o f 013.1 k e l v i n (013 f o r t h e Models DRC-7 and DRC-7C) on t h e r e a d o u t / c o n t r o l l e r d i s p l a y . S e t t h e v o l t a g e s t a n d a r d t o 1.1736 v o l t s and a d j u s t t h e potentiometer l a b e l e d "FS" f o r a f r o n t panel d i s p l a y r e a d i n g o f 026.0 k e l v i n (026 f o r Models DRC-7 and DRC-7C). R19 S e t t h e v o l t a g e s t a n d a r d t o 1.1283 v o l t s and a d j u s t potentiometer f o r a r e a d i n g o f 028.0 k e l v i n (028 f o r Models DRC-7 and DRC-7C). F i n a l l y , set t h e v o l t a g e s t a n d a r d t o 0.9811 v o l t s and a d j u s t p o t e n t i o m e t e r R26 for a r e a d i n g of 077.4 k e l v i n (077 on Models DRC-7 and DRC-7C), on t h e f r o n t panel d i s p l a y . The f i n a l c a l i b r a t i o n is t h e same as o u t l i n e d under "Customer C a l i b r a t i o n " i n S e c t i o n 3 5,6 Alignment o f C o n t r o l l e r S e c t i o n 5.6.1 Mode1 DRC-7C No alignment o r adjustments are r e q u i r e d f o r t h i s s e c t i o n . 5.6.2 Model DRC-70C With t h e c i r c u i t board removed following i n s t r u c t i o n s i n S e c t i o n 5.8, connect t h e f l a t ribbon c a b l e connector and t h r e e s i n g l e wire connectors t o t h e i r a p p r o p r i a t e s p o t s on t h e p r i n t e d c i r c u i t board using c l i p leads. Connect a BOO ohm, 20 watt load a c r o s s t h e h e a t e r t e r m i n a l s . t h e f i n e t u n i n g c o n t r o l t o minimum. Set Connect an o s c i l l o s c o p e a c r o s s t h e BOO ohm l o a d as follows: a) Time s e t t i n g a t 50 m s e c . / d i v . b) Voltage s e t t i n g t o 5 v o l t s / d i v . using times 1 probe c) S e t coupling t o Auto d) S e l e c t t r i g g e r mode f o r l i n e S e t t h e thumbwheel switch t o 150.0 and t u r n power ON. Adjust t h e s e n s o r i n p u t v o l t a g e such t h a t t h e meter d i s p l a y reads 1 4 9 . 0 and i n c r e a s e t h e f i n e t u n i n g c o n t r o l u n t i l 10 v o l t s AC i s i n d i c a t e d across t h e 100 ohm resistor. The AC waveform w i l l appear throughout t h e time sweep. Adjust t h e s e n s o r v o l t a g e such t h a t t h e d i g i t a l d i s p l a y i n d i c a t e s 149.6. S e t R129 u n t i l . 9 c y c l e s o f t h e AC waveform appears on t h e screen. The p r o p o r t i o n a l bandwidth h a s now been a d j u s t e d f o r p r o p e r cycling. 5.7 Troubleshooting Panel Meter I n normal use, t h e panel meter does not r e q u i r e c a l i b r a t i o n . However, should t h e r e a d i n g on t h e panel meter d i f f e r by more than 2 K from t h e analog output, c a l i b r a t i o n o f t h e panel meter i s i n d i c a t e d . A t t h i s p o i n t , c o n s u l t manufactures. I f it is i n d i c a t e d t h a t t h e panel meter i s f a u l t y , t h e following procedure should b e followed f o r removal, 5.8 C i r c u i t Board Removal Disconnect a l l e l e c t r i c a l connections t o t h e t e r m i n a l s t r i p at t h e r e a r of t h e instrument. Remove t h e s i x screws l o c a t e d at t h e r e a r o f t h e instrument and s l i d e t h e board g e n t l y o u t o f t h e case. On Models DRC-7C and DRC-70C, t o remove t h e c i r c u i t board, s l i d e t h e board o u t o f t h e c a s e approximately 1", disconnect t h e t h r e e s i n g l e w i r e s connect by p u l l i n g t h e p i n s down. The connectors are o f d i f f e r e n t s i z e s t o f a c i l i t a t e t h e i r c o r r e c t replacement. S l i d e t h e board u n t i l i t i s approximately h a l f way o u t of t h e case. Disconnect t h e connector t i e d t o t h e f l a t ribbon c a b l e by p u l l i n g downward on t h e f l a t c a b l e . S l i d e t h e c i r c u i t board a l l t h e way o u t . 5.9 Panel Meter Removal Removal of t h e panel meter i s accomplished a f t e r t h e p r i n t e d c i r c u i t board i s removed. Unscrew two screws i n t h e f r o n t s e c t i o n o f t h e piggy-back panel meter board from t h e main r e a d o u t / c o n t r o l l e r mother board. S l i d e t h e meter forward o u t of t h e connector. 5.10 Parts L i s t , P r i n t e d C i r c u i t Board Component Locator, and Schematie Table 5.1 PARTS LIST REF. DESIG. DESCRIPTION R1 R2 R3 R4 R5 R6 R7 R8 R9 R 10 R11 R 12 R1 3 R14 R15 R16 R17 R 18 R19 R20 R2 1 R2 2 R23 R24 R25 R2 6 R27 R2 8 R29 R30 R3 1 R32 R33 R34 R35 1 Meg., 1/8W, 1% 100 K , 1/8W, 1% 324, 1/8W, 1% 511 K, 1/8W, 1% 100 K, 1/8W, 1% 513, 1/8W, 1% 634 K, 1/8W, 1% 388, 1/8W, 1% 100 K , 1/8W, 1% 634 K, 1/8W, 1% 100 K, 1/8W, 1% 931, 1/8W, 1% 475 K, 1/8W, 1% 100 K, 1/8W, 1% 1004, 1/8W, 1% 63.4 K, 1/8W, 1% 100 K, 1/8W, 1% 1.02 K, 1/8W, 1% 50 ohm, VARIABLE 1 3 . 3 K, 1/8W, 1% 100 K, 1/8W, 1% 98.8 K, 1/8W, 1% 8.47 K, 1/8W, 1% 100 K, 1/8W, 1% 1.05 K, 1/8W, 1% 50 ohm, VARIABLE 100, 1/4W, 5% 90.9 K, 1/8W, 1% 5.11 K, 1/8W, 1% 51.1, 1/8W, 1% 6.49 K, 1/8W, 1% 100 K, 1/8W, 1% 1 0 K, VARIABLE 50 ohm, VARIABLE 1.1 Meg., 1/8W, 1% MODEL DESIG. LAKE SHORE PART NO. RN60D1004F RN60D1003F RN60D3240F RN60D5 113F RN60D1003F RN60D5130F RN60D634 3F RN60D3880F RN60D1003F RN60D6343F RN60D1003F RN60D9 310 F RN60D4753F RN60B100 3F RN60D10040F RN60D6 34 2F RN60D1003F RN60D1021F 3006P-1-500 RN60D11332F RN6001003F RN60D9882F RN60D847 1F RN60D1003F RN60D105BF 3006P 1-500 RC RO 7G10 1JS RN60D9092F RN60D5111F RN60D51RlF RN60D6491F RN6OD1003F 3006P-1-103 3006P-1-500 RN65D1104F - REF. DESIG. R36 R 37 R38 R39 R40 R4 1 R4 2 R4 3 R4 4 R4 5 R46 R47 R4 8 R49 R50 R5 1 R52-R69 R70 R7 1 R7 2 R7 3 R74 R75 R76 & R77 R7 8 R79 R80 R 81 R82 R 83 R84, 85 R86, 87 R88 R89 R90, 91 R9 2 DESCRIPTION MODEL DESIG. LAKE SHORE PART NO. 324, 1/8W, 1% 419, 1/8W, 1% 234, 1/8W, 1% 377, 1/8W, 1% 100, 1/4W, 5% 10 K , 1/8W, 1% 1 0 K , 1/8W, 1% 104, 1/8W, 1% 69.8, 1/8W, 1% 115, 1/8W, 1% 5.11 K , 1/8W, 1% 147 K, 1/8W, 1% 487 K , 1/8W, 1% 634 K , 1/8W, 1% 100, 1/4W, 5% 100, 1/4W, 5% RN60D3240F RN60D4190F RN60D2 340F RN60D3770F RCR07G101JS RN60D1002F RN60D1002F RN60D1040F RN60D69R8F RN60D1150F RN60D511F RN60D1473F RN60D48 73F RN60D6343F RCR07G101JS RC R0 7G 101J S TRIM, 1/8W, 1% 100 ohm, VARIABLE 2 K, 1/8W, 1% 100 K , 1/8W, 1% 100 K, 1/8W, 1% 51.1 K , 1/8W, 1% RN60D 3006P-1-101 RN60D2001F RN60D1003F RN60D1003F RN60D5112F 402 K, 1/8W, 1% 50 K , VARIABLE 10 K , 0.1%, TEL LABS 22.1 K , 1/8W, 1% 500 ohm, VARIABLE 13.3 K, 1/8W, 1% 100, 1/4W, 5% 100 K , 0.1%, TEL LABS 100 K , 1/8W, 1% 100 ohm, VARIABLE 10, 1/8W, 1% 100 K, 1/8W, 1% RN60D4023F 3006P-1-503 SA1 RN60D2212F 3006P-1-501 RN60D1332F RCR07G101JS SA1 RN60D1003F CTSX20 1R10 1B RN60D 10R0 F RN60D1003F REF. DESIG. R9 3 R9 4 R 95 R96, R97 R9 8 R99 R100- 113 R114 R115 R116 R117 R118 R119 R120 R121 R122 R123 R124 R125 R126 R127 R128 R129 R130 R131 R132 R133 R134, 135 R136 C1-6 C7 C8-10 C11 C12 DESCRIPTION MODEL DESIG. LAKE SHORE PART NO. 10 K , 1/8W, 1% 200 K , 1/8W, 1% 10 K , 1/8W, 1% RN60D1002F RN60D2003F RN60D1002F 50 ohm, VARIABLE 500 ohm, VARIABLE 3006P-1-500 3006P-1-501 47 K, 1/4W, 5% 300, 1/4W, 5% 22 K , 1/4W, 5% 82.5 K , 1/8W, 1% 40.2 K , 1/8W, 1% 20 K, 1/8W, 1% 10 K , 1/8W, 1% 22 K , 1/4W, 5% 820, 1/4W, 5% 6.8 K , 1/4W, 5% 22 K , 1/4W, 5% 330, 1/4W, 5% 150 K, 1/8W, 1% 1 0 K, 1/8W, 1% 22.1 K , 1/8W, 1% 5000, VARIABLE 100 K , 1/4W, 5% 6.8 K, 1/4W, 5% 100 K , 1/4W, 5% 22 K , 1/4W, 5% 39 K, 1/4W, 5% 100, 1/4W, 5% RC R0 7G4 7 3J S RC R0 7G 30 1J S RC R0 7G 2 2 3F RN60D8252F RN60D4022F RN60D2002F RN60D1002F RCR07G223F RCR07G821JS RCR07G682JS RC R0 7G 2 2 3F RCR07G330JS 2.2 MFD 100 PFD 0.05 MFD, 500 V 2 . 2 MFD 196D2250025 DD101 5GA & 50 196D2250025 RN60D1503F RN60D1002F RN60D2212F 3006P-1-502 RCR07G104J S RCR07G682JS RCR0 7G 104J S RCR07G223F RCR07G393JS RC R0 7G 10 1J S . REF DESIG. C13, 14 C15 C16 C17 C18 C19 C20 C21. C22 C23 C24 DESCRI PT I ON MODEL DESIG, LAKE SHORE PART NO. 0.05 MFD, 500 V 5GAS50 0.1 MFD, 50 P F D 100 MFD, 0.05 MFD, 0.1 MFD, DD104 DD500 TE1211 5GAS50 DD104 500 V 25 V 500 V 500 V 22 MFD, 15 V 196D226X0015 1 96D22500 35 5GAS50 C26 C27 C 2 8 , 29 C30 C31 C 3 2 - 34 C35 C36 C37 220 MFD, 35 V 0.05 MFD, 500 V 100 MFD, 10 V 1000 P F D 196D107V0010 DD102 10 MFD, 25 V 1000 P F D 2.2 MFD, 25 V 10 MFD, 25 V 0.05 MFD, 500 V 2.2 MFD, 25 V 196D106X0025 DD1 02 196D2250025 196D106X0025 5GAS50 196D2250025 CR1-4 CR5-20 SILICON RECTIFIER SI L I CON D I ODE I N 4004 I N 914 Q1-5 Q6 TRANSISTOR TRANS I STO R 2N4124 2N2905 Z2 Z3 I.C. I.C. I.C. I.C. I.C. I.C. LF355H LM308A RC4 136 CD4 016AE R C 4 1 36 CD40 16AE C25 Z4, 5 Z6 Z7 Z8 Z9 AMPLIFIER AMPLIFIER AMPLIFIER ANALOG SWITCH AMPLIFIER ANALOG SWITCH REF. DESIG. Z1 0 Z11 Z12 Z1 3 Z14 Z15, 16 Z17 Z18-20 Z21 Z2 2 Z23 Z 24 DESCRI PT I ON I. C. I.C. I.C. I.C. I.C. I.C. I.C. . I .C I.C. I.C. MODEL DESIG. COMPARATOR AMPLIFIER NANDGATE NORGATE COUNTER COUNTER F L I P FLOP COMPARATOR NANDGATE AMPLIFIER LAKE SHORE PART NO. CD4030AE LF355H CD4011AE CD4001AE CD4029AE CD45 18BE CD4O1 3AE CD4030AE CD4011AE CA3747 Z25 I . C. VOLTAGE REGULATOR I . C . RESISTANCE NETWORK (BOURNS) LM305 4116R M1 M2 D I G I T A L PANEL METER (WESTON) DIGITAL PANEL METER (GRALEX) 1230 37 T1 TRANSFORMER (GRAND) S5332 K1 RELAY (HAMLIN) 701-1 1-5 I NDI CAT0 R (LE D-HE W LETT/PACK ARD) 5082-4684 SW1 SWITCH 7101-AV2 F1 F2 FUSE C L I P S ( 2 each) FUSE, 1 a m p FUSE, 1/8 amp 798 AGC AGC CONNECTOR, FLAT CABLE CONNECTOR 14 P I N SOCKET (For Z4-8, 10-13, 17-22) 16 P I N SOCKET (For Z14-16) Printed C i r c u i t B o a r d Schematic Diagram Schematic D i a g r a m Schematic D i a g r a m Schematic D i a g r a m 3428- 2002 ISM15DRAS 14MSLSC 16MSLSC D60109 D270276 D270275 B270274 D270279 E x c e p t w h e r e noted under column labeled "MODEL DESIGN”, a l l p a r t s listed are for a11 u n i t s . 1-Model DRC-7, 2-Model DRC-7C, 3-Mode1 DRC-70, and 4-Mode1 DRC-70C. SECTION V I APPEND1 XES DRC-7 SERIES STANDARD SILICON DIODE TABLE 4-400 K A- 020-009 TABLE 6.1 Temp. (K) 4 4.2 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 35 40 45 50 55 60 Voltage (V) 2.46200 2.45000 2.40200 2.34200 2.28964 2.23727 2.18491 2.13255 2.08018 2.02782 1.97545 1.92309 1.86442 1.80574 1.74707 1.68839 1.61309 1.53778 1.46248 1.38717 1.31187 1.26000 1.20813 1.17357 1.13900 1.12833 1.11769 1.10705 1.09375 1 08045 1.06715 1.05385 1.04055 1.02725 Temp. (K) Voltage (V) Temp. 65 70 75 77.34 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 2 15 2 20 225 1.01395 1.00065 0 98735 0.98113 0.97405 0.96017 0.94630 0.93242 0.91855 0.90467 0.89079 0.87692 0 .86304 0.84917 0.83529 0.82141 0.80754 0.79366 0.77979 0.76591 0.75203 0.73816 0.72428 0.71041 0.69653 0,68265 0.66878 0.65490 0.64103 0.62715 0.61327 0.59940 0.58552 0.57165 2 30 2 35 240 245 250 255 260 265 270 275 2 80 2 85 290 295 300 305 310 315 320 325 330 335 340 345 350 35 5 36 0 36 5 370 375 380 385 390 395 400 . (K) Voltage (V) 0.55777 0.54389 0.53002 0.51614 0.50227 0.48839 0.47451 0.46064 0.44676 0.43289 0.41901 0 .40513 0.39126 0.37738 0.36351 0.34963 0.33575 0.32188 0.30800 0.29413 0.28025 0.26637 0.25250 0.23862 0.22475 0.21087 0.19699 0.18312 0.16924 0,15537 0.14149 0.12761 0.11374 0.09986 0.08599