Download CAN - CAI812

Overview
1. Functional Characteristics
1.1 Overview
1.1.1 Description of the Module
e le c tr ic a l is o la tio n
P 2
C
C h a n n e l 1
A
N
P h y s ic a l
C A N
L a y e r
P 3
B
J 4
S h u n t
-
P 1
P o w e r S u p p ly
In p u t: 2 4 V (D C )
O u tp u t: 5 V (D C )
C A N
W a tc h d o g
I/O
Id e n tifie r
µ C
8 0 C 5 9 2
d ig ita l
I/O P o rts
8
C h a n n e l
1 2 B it
A /D
L T C 1 2 9 4
C h a n n e l 8
d ig ita l
P o rts
+
J 1 8
-
E P R O M
P 4
E m e rg e n c y S to p
a n d
M e s s a g e O u tp u t
T e r m in a l B lo c k
S
T e r m in a l B lo c k
U
+
2 5 6 B y te
R A M
S h u n t
e x te rn a l
S R A M
J 3
Fig. 1.1.1: Functional block diagram of the CAI812
The CAI812 module offers 8 differential analog inputs with a 12-bit resolution. The input-voltage area
can be selected via jumpers separately for each channel between ±5 V and ±10 V. Furthermore the
module can be configurated via jumpers channel-by-channel for current measurement (±20 mA,
±40 mA). By means of the software it is possible to select whether the input signals are to be evaluated
bipolarly or unipolarly.
The analog inputs are evaluated by means of the A/D converter LTC1294, which is galvanically
isolated from the CAN assemblies.
The firmware offers the possibility to let the user select zero point and measuring area of the individual
channels.
The physical CAN layer is galvanically isolated from the other local assemblies and is designed
according to ISO 11898 for a bitrate of 1Mbit/s. Other physical layers are optionally realizable via
mountable piggyback.
CAN-CAI812 Hardware Rev. 5.1
3