Siemens SIMATIC S7-1200 - Page 1483

Technical specifications
A.11 Thermocouple and RTD signal modules (SMs)
S7-1200 Programmable controller
System Manual, V4.2, 09/2016, A5E02486680-AK
1483
Table A- 179 Resistance
Range
Under range
minimum
Nominal range
low limit
Nominal range
high limit
Over
range
maximum
1
Normal range
accuracy
@ 25 °C
Normal range accu-
racy -20 °C to 60 °C
150 Ω
n/a
0 (0 Ω)
27648 (150 Ω)
176.383 Ω
±0.05%
±0.1%
300 Ω n/a 0 (0 Ω) 27648 (300 Ω) 352.767 Ω ±0.05% ±0.1%
600 Ω
n/a
0 (0 Ω)
27648 (600 Ω)
705.534 Ω
±0.05%
±0.1%
1
Resistance values above the over-range minimum value are reported as +32767.
Note
The module reports 32767 on any activated channel with no sensor connected. If open wire
detection is also enabled, the module flashes the appropriate red LEDs.
When 5
00 Ω and 1000 Ω RTD ranges are used with other lower value resistors, the error
may increase to two times the specified error.
Best accuracy will be achieved for the 10 Ω RTD ranges if 4 wire connections are used.
The resistance of the connection wires in
2 wire mode will cause an error in the sensor
reading and therefore accuracy is not guaranteed.
Table A- 180 Noise reduction and update times for the RTD modules
Rejection frequency selec-
tion
Integration time
Update time (seconds)
4-channel module
8-channel module
400 Hz (2.5 ms) 10 ms
1
4-/2-wire: 0.142
3-wire: 0.285
4-/2-wire: 0.285
3-wire: 0.525
60 Hz (16.6 ms) 16.67 ms 4-/2-wire: 0.222
3-wire: 0.445
4-/2-wire: 0.445
3-wire: 0.845
50 Hz (20 ms) 20 ms 4-/2-wire: 0.262
3-wire: .505
4-/2-wire: 0.524
3-wire: 1.015
10 Hz (100 ms) 100 ms 4-/2-wire: 1.222
3-wire: 2.445
4-/2-wire: 2.425
3-wire: 4.845
1
To maintain module resolution and accuracy when the 400 Hz filter is selected, the integration time is 10 ms. This selec-
tion also rejects 100 Hz and 200 Hz noise.
Note
After power is applied, the module 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 av
ailable on that channel. Your user program may need to allow for this initialization
time. Because the configuration of the module can vary the length of the initialization time,
you should verify the behavior or the module in your configuration. If requir
ed, you can
include logic in your user program to accommodate the initialization time of the module.