Selected measuring method
Measuring range
(type of sensor)
Measuring range module set‐
tings
Description
RTD-3L: Thermal resistance
(linear, 3-conductor connec‐
tion) (temperature measure‐
ment)
Pt 100 Climatic
Pt 200 Climatic
Pt 500 Climatic
Pt 1000 Climatic
Ni 100 Climatic
Ni 1000 Climatic
Pt 100 Standard
Pt 200 Standard
Pt 500 Standard
Pt 1000 Standard
Ni 100 Standard
Ni 1000 Standard
A
The digitized analog values
are listed in the section "Rep‐
resentation of analog values
for analog input channels" in
the temperature range.
RTD-4L: Thermal resistance
(linear, 4-conductor connec‐
tion) (temperature measure‐
ment)
Default
The "voltage" measuring method and "± 10 V" measuring range are set by default in STEP 7.
You can use this combination of measuring method and measuring range without configuring
the SM 431; AI 16 x 16 Bit in STEP 7.
Wire break monitoring
The wire break check is intended primarily for temperature measurements (TC, RTD) or
resistance measurements. Always configure the wire break check in these cases as this
ensures that in the event of a wire break the measured value provided by the module accepts
the data for overrun 7FFFH.
Special characteristics of the wire break check for the voltage measurement methods
In some transducers, incorrect measured values may occur due to the fact that the wire break
check is enabled. If so, disable the wire break check.
Reason: Some transducers try to correct the test current and in doing so corrupt the setpoint
value they provide.
Points to note about the wire break check when current sensors are connected
A wire break check of current sensors is not possible for the SM 431; AI 16 x 16 Bit except in
life-zero areas. You can therefore only configure the wire break check for the "Current (4-wire
transducer)" measuring method and the "4 to 20 mA" measuring range.
Checking for reference channel errors when connecting thermocouples
If you have connected a thermocouple, you can then enable the "Reference channel error"
diagnostics if you have configured an "RTD on Channel 0" or "Reference Temperature Value"
reference junction.
Analog modules
5.23 Analog input module SM 431; AI 16 x 16 Bit (6ES7431-7QH00-0AB0)
S7-400 Automation System Module Data
Reference Manual, Ausgabe 11/2016, A5E00850736-08
291