Siemens SIMATIC S7-1200 - Page 1524

Technical specifications
A.14 Analog signal boards (SBs)
S7-1200 Programmable controller
1524 System Manual, V4.2, 09/2016, A5E02486680-AK
Table A- 231 Diagnostics
Technical data
SB 1231 AI 1 x 16 bit RTD
Overflow/underflow
1, 2
Yes
Wire break
3
Yes
1
The overflow and underflow diagnostic alarm information will be reported in the analog data values even if the alarms
are disabled in the module configuration.
2
For resistance ranges underflow detection is never enabled.
3
When wire break alarm is disabled and an open wire condition exists in the sensor wiring, the module may report ran-
dom values.
The SM 1231 RTD analog signal board measures the value of resistance connected to the
signal board inputs. The measurement type can be selected as either "Resistor" or "Thermal
resistor".
● "Resistor": The nominal range full scale value will be decimal 27648.
● "Thermal resistor": The value will be reported in degrees multiplied by ten (for example,
25.3 degrees will be reported as decimal 253). The climatic range values will be reported
in degrees multiplied by one hundred (for example, 25.34 degrees will be reported as
decimal 2534).
The SB 1231 RTD signal board supports measurements with 2-wire, 3-wire and 4-wire
connections to the sensor resistor.