553BTechnical specifications
A.7 Thermocouple and RTD signal modules (SMs)
S7-1200 Programmable controller
718
System Manual, 11/2011, A5E02486680-05
Table A- 105 Resistance
Range
Under range
minimum
1
Nominal range
low limit
Nominal range
high limit
Over range
maximum
2
Normal range
accuracy
@ 25°C
Normal range
accuracy
0°C to 55°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
RTD values below the under-range minimum value are reported as -32768.
2
RTD values above the over-range minimum value are reported as -32768.
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 500 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- 106 Noise reduction and update times for the RTD modules
Update time (seconds)
Rejection frequency
selection
Integration time
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
selection also rejects 100 Hz and 200 Hz noise.
