Siemens SIMATIC S7-1200 - Page 1521

Technical specifications
A.14 Analog signal boards (SBs)
S7-1200 Programmable controller
System Manual, V4.2, 09/2016, A5E02486680-AK
1521
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
Type
Under range
minimum
1
Nominal
range low limit
Nominal range
high limit
Over range
maximum
2
Normal range
3
accuracy @ 25 °C
Normal range
3,
accuracy
-20 °C to 60 °C
J
-210.0 °C
-150.0 °C
1200.0 °C
1450.0 °C
±0.3 °C
±0.6 °C
K -270.0 °C -200.0 °C 1372.0 °C 1622.0 °C ±0.4 °C ±1.0 °C
T
-270.0 °C
-200.0 °C
400.0 °C
540.0 °C
±0.5 °C
±1.0 °C
E -270.0 °C -200.0 °C 1000.0 °C 1200.0 °C ±0.3 °C ±0.6 °C
R & S
-50.0 °C
100.0 °C
1768.0 °C
2019.0 °C
±1.0 °C
±2.5 °C
B
0.0 °C
200.0 °C
800.0 °C
--
±2.0 °C
±2.5 °C
--
800.0 °C
1820.0 °C
1820.0 °C
±1.0 °C
±2.3 °C
N
-270.0 °C
0.0 °C
1300.0 °C
1550.0 °C
±1.0 °C
±1.6 °C
C
0.0 °C
100.0 °C
2315.0 °C
2500.0 °C
±0.7 °C
±2.7 °C
TXK/XK(L)
-200.0 °C
-150.0 °C
800.0 °C
1050.0 °C
±0.6 °C
±1.2 °C
Voltage -32511 -27648
-80mV
27648
80mV
32511 ±0.05% ±0.1%
1
Thermocouple values below the under-range minimum value are reported as -32768.
2
Thermocouple values above the over-range minimum value are reported as 32767.
3
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
30 minutes of warm-up time to meet this specification.
Table A- 226 Filter selection table for the SB 1231 Thermocouple
Rejection frequency (Hz)
Integration time (ms)
Signal board update time (seconds)
10
100
0.306
50
20
0.066
60
16.67
0.056
400
1
10
0.036
1
To maintain module resolution and accuracy when 400 Hz rejection is selected, the integration time is 10 ms. This
selection also rejects 100 Hz and 200 Hz noise.