Siemens SIMATIC S7 System Manual page 737

Thermocouple Under range
Type minimum
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 warmup time to meet this specification.
Table A- 139 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.
It is recommended for measuring thermocouples that a 100 ms integration time be used. The
use of smaller integration times will increase the repeatability error of the temperature
readings.
Note
After power is applied to the module, it performs internal calibration for the analog to digital
converter. During this time, the module reports a value of 32767 on each channel until valid
data is available on that channel. Your user program may need to allow for this initialization
time.
S7-1200 Programmable controller
System Manual, 11/2011, A5E02486680-05
Nominal Nominal range
range low limit high limit
1
-150.0°C 800.0°C
-27648 27648
-80mV 80mV
Integration time (ms)
100
20
16.67
10
553BTechnical specifications
A.9 Analog signal boards (SBs)
Over range Normal range
maximum accuracy @ 25°C
2
1050.0°C ±0.6°C
32511 ±0.05%
Signal board update time (seconds)
0.306
0.066
0.056
0.036
Normal range
3 3,
accuracy
0°C to 55°C
±1.2°C
±0.1%
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