The SM 1231 thermocouple modules enable temperatures to be measured with high precision using established thermocouples. In addition, low level analog signals in the ±80 mV range can be recorded. The SM 1231 thermocouple modules can be used with the CPUs of the S7-1200 series.
The SM 1231 thermocouple modules exhibit the same structural features as the other modules of the S7-1200 series:
Different measurement ranges:
Thermocouples of types J, K, T, E, R, S and N; analog signal recording ±80 mV.
Check for open lines.
Compensation of the cold connecting point:
Faults caused by contact voltages at the connection between thermocouple and module are prevented; when recording analog signals (±80 mV), the compensation is automatically deactivated.
Temperature scaling:
The measured temperature can be shown in °C or °F.
SIMATIC S7-1200, Analog input, SM 1231 TC, 4 AI thermocouples | |
General information | |
Product type designation | SM 1231, AI 4x16 bit TC |
Supply voltage | |
Rated value (DC) | 24 V |
Input current | |
Current consumption, typ. | 40 mA 80 mA |
from backplane bus 5 V DC, typ. | |
Power loss | |
Power loss, typ. | 1.5 W |
Analog inputs | |
Number of analog inputs | 4; Thermocouples ±35 V Degrees Celsius/degrees Fahrenheit |
permissible input voltage for voltage input (destruction limit), max. | |
Technical unit for temperature measurement adjustable | |
Input ranges | |
| Yes No Yes; J, K, T, E, R, S, N, C, TXK/XK(L); voltage range: ±80 mV No No |
Input ranges (rated values), voltages | |
| Yes ≥1 MOhm |
Input ranges (rated values), thermocouples | |
| Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes |
Thermocouple (TC) | |
Temperature compensation | |
- parameterizable | No |
Analog value generation for the inputs | |
Measurement principle | integrating |
Integration and conversion time/resolution per channel | |
| 15 bit; + sign No 85 dB at 50 / 60 / 400 Hz |
Smoothing of measured values | |
| Yes |
Errors/accuracies | |
Temperature error (relative to input range), (+/-) | 25 °C ±0.1%, to 55 °C ±0.2% total measurement range 0.5 % |
Repeat accuracy in steady state at 25 °C (relative to output range), (+/-) | |
Interference voltage suppression for f = n x (f1 +/- 1 %), f1 = interference frequency | |
| 120 dB |
Interrupts/diagnostics/status information | |
Alarms | Yes Yes; Can be read out |
Diagnostics function | |
Alarms | |
| Yes |
Diagnoses | |
| Yes Yes |
Diagnostics indication LED | |
| Yes Yes |
Degree and class of protection | |
IP degree of protection | IP20 |
Standards, approvals, certificates | |
CE mark | Yes Yes Yes |
CSA approval | |
UL approval | |
cULus | Yes Yes Yes Yes |
FM approval | |
RCM (formerly C-TICK) | |
KC approval | |
Marine approval | Yes |
Ambient conditions | |
Free fall | |
| 0.3 m; five times, in product package |
Ambient temperature during operation | |
| -20 °C 60 °C -20 °C 60 °C -20 °C 50 °C |
Ambient temperature during storage/transportation | |
| -40 °C 70 °C |
Air pressure acc. to IEC 60068-2-13 | |
| 795 hPa 1 080 hPa 660 hPa 1 080 hPa |
Relative humidity | |
| 95 % |
Pollutant concentrations | |
| S02: < 0.5 ppm; H2S: < 0.1 ppm; RH < 60% condensation-free |
connection method / header | |
required front connector | Yes |
Mechanics/material | |
Enclosure material (front)
| Yes |
Dimensions | |
Width | 45 mm 100 mm 75 mm |
Height | |
Depth | |
Weights | |
Weight, approx. | 180 g |