Download - Power Logic

Temperature Monitoring
ANSI Code 38/49T
Protection Functions
Operation
This protection is associated with a Pt100 platinum (100 Ω at 32°F or 0°C), Ni100,
or Ni120 nickel type resistance temperature detector (RTD), in accordance with the
IEC 60751 and DIN 43760 standards.
b Picks up when the monitored temperature is greater than the Ts set point
b Has two independent set points:
v Alarm set point
v Tripping set point
b When the protection is activated, it detects whether the RTD is shorted
or disconnected:
v RTD shorting is detected if the measured temperature is less than
-31°F (-35°C, measurement displayed “****”)
v RTD disconnection is detected if the measured temperature is greater than
+401°F (+205°C, measurement displayed “-****”)
Note: If an RTD fault is detected, the set point output relays are blocked (the protection outputs
are set to zero). Also, "RTD fault" is displayed in the control matrix and an alarm message
is generated.
Block Diagram
MT10878
T < +401 °F
RTD
T > Ts1
Set Point 1
T > Ts2
Set Point 2
RTD’s Fault
T > -95 °F
Characteristics
Ts1 and Ts2 Set Points
°F
°C
Setting
32–356°F
0–180°C
±2.7°F
±1.5°C
Accuracy (1)
Resolution
1°F
1°C
Pick-Up/Drop-Out Difference
3°C ±0.5°
Characteristic Times
Operation Time
<5s
(1) See Connection of MET1482 Module for accuracy derating according to the wiring
cross section.
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