Siemens S7-1200 System Manual page 955

For optimum operation of the cold junction compensation, the thermocouple module must be
located in a thermally stable environment. Slow variation (less than 0.1 °C/minute) in
ambient module temperature is correctly compensated within the module specifications. Air
movement across the module will also cause cold junction compensation errors.
If better cold junction error compensation is needed, an external iso-thermal terminal block
may be used. The thermocouple module provides for use of a 0 °C referenced or 50 °C
referenced terminal block.
Selection table for the SB 1231 thermocouple
The ranges and accuracy for the different thermocouple types supported by the SB 1231
Thermocouple signal board are shown in the table below.
Table A- 225 SB 1231 Thermocouple selection table
Thermocouple Under range
Type minimum
J -210.0 °C
K -270.0 °C
T -270.0 °C
E -270.0 °C
R & S -50.0 °C
B 0.0 °C
--
N -270.0 °C
C 0.0 °C
TXK/XK(L) -200.0 °C
Voltage -32511
Thermocouple values below the under-range minimum value are reported as -32768.
1
Thermocouple values above the over-range minimum value are reported as 32767.
2
Internal cold junction error is ±1.5 °C for all ranges. This adds to the error in this table. The signal board requires at least
3
30 minutes of warm-up time to meet this specification.
Table A- 226 Filter selection table for the SB 1231 Thermocouple
Rejection frequency (Hz)
10
50
60
400
1
To maintain module resolution and accuracy when 400 Hz rejection is selected, the integration time is 10 ms. This
1
selection also rejects 100 Hz and 200 Hz noise.
S7-1200 Programmable controller
System Manual, 03/2014, A5E02486680-AG
Nominal Nominal range
range low limit high limit
1
-150.0 °C 1200.0 °C
-200.0 °C 1372.0 °C
-200.0 °C 400.0 °C
-200.0 °C 1000.0 °C
100.0 °C 1768.0 °C
200.0 °C 800.0 °C
800.0 °C 1820.0 °C
0.0 °C 1300.0 °C
100.0 °C 2315.0 °C
-150.0 °C 800.0 °C
-27648 27648
-80mV 80mV
Integration time (ms)
100
20
16.67
10
A.12 Analog signal boards (SBs)
Over range Normal range
maximum accuracy @ 25 °C
2
1450.0 °C ±0.3 °C
1622.0 °C ±0.4 °C
540.0 °C ±0.5 °C
1200.0 °C ±0.3 °C
2019.0 °C ±1.0 °C
-- ±2.0 °C
1820.0 °C ±1.0 °C
1550.0 °C ±1.0 °C
2500.0 °C ±0.7 °C
1050.0 °C ±0.6 °C
32511 ±0.05%
Signal board update time (seconds)
0.306
0.066
0.056
0.036
Technical specifications
Normal range
3 3,
accuracy
-20 °C to 60 °C
±0.6 °C
±1.0 °C
±1.0 °C
±0.6 °C
±2.5 °C
±2.5 °C
±2.3 °C
±1.6 °C
±2.7 °C
±1.2 °C
±0.1%
955