Siemens S7-1200 - Page 920

Technical specifications
A.9 Thermocouple and RTD signal modules (SMs)
S7-1200 Programmable controller
920 System Manual, 03/2014, A5E02486680-AG
Model
SM 1231 AI 4 x 16 bit TC
SM 1231 AI 8 x 16 bit TC
Cable length (meters)
100 meters to sensor max.
100 meters to sensor max.
Wire resistance
100 Ω max.
100 Ω max.
Table A- 165 Diagnostics
Model
SM 1231 AI 4 x 16 bit TC
SM 1231 AI 8 x 16 bit TC
Overflow/underflow
1
Yes
Yes
Wire break (current mode only)
2
Yes
Yes
24
VDC low voltage
1
Yes Yes
1
The overflow, underflow and low voltage diagnostic alarm information will be reported in the analog data values even if
the alarms are disabled in the module configuration.
2
When wire break alarm is disabled and an open wire condition exists in the sensor wiring, the module may report
random values.
The SM 1231 Thermocouple (TC) analog signal module measures the value of voltage
connected to the module inputs. The temperature measurement type can be either
"Thermocouple" or "Voltage".
● "Thermocouple": The value will be reported in degrees multiplied by ten (for example, 25.3
degrees will be reported as decimal 253).
● "Voltage": The nominal range full scale value will be decimal 27648.