Siemens SIMATIC Manual page 382

Analog modules
6.9 Analog input module SM 331; AI 8 x RTD; (6ES7331-7PF01-0AB0)
Figure 6-22
Note
- Always use channel n (in this case channel 0) for measurement
- Short-circuit unused channels (in this case channel 1) or connect them in order to avoid
diagnostic results with a resistance of the rated range (eg.100 ohms at Pt 100)
Wiring
Incorrect wiring of the 3-wire connection can result in unpredictable operation of the module
and dangerous conditions in the plant.
Wiring: 3-wire connection
With a 3-wire connection to the SM 331; AI 8 x RTD, you need to set a jumper between M
and I
Always ensure that the connected I
thermometer.
Wiring: 2-wire connection
With a 2-wire connection to the SM 331; AI 8 x RTD, you need to set a jumper between M
and I
There is no compensation of the line resistance with a 2-wire connection. The line
resistances are also measured!
382
Unused channel
CAUTION
.
C+
as well as M and I
C+ - C-
and M cables are directly to the resistance
C
.
S7-300 Module data
Manual, 06/2017, A5E00105505-AJ
+
+