Siemens Simatic M7-400 Reference Manual page 333

5.22.2 Measuring Methods and Measuring Ranges of the SM 431;
AI 16 16 Bit
Measuring Methods
You can set the following measuring methods for the input channels:
• Voltage measurement
• Current measurement
• Resistance test
• Temperature measurement
You specify the setting by means of the measuring range modules on the module
and the "Measuring Type" parameter in STEP 7.
Circuit Variants for the Channels
Two channels are set in each case with the measuring range module. There are
therefore restrictions as regards the measuring method for the adjacent channels
0/1, 2/3, 4/5, 6/7, 8/9, 10/11, 12/13 and 14/15, as shown in the following table:
Table 5-66 Selection of the Measuring Method for Channel n and Channel n+1 of the SM 431;
AI 16 16 Bit
Disabled
Meas. Type
Channel n+1
Meas. Type
Channel n
Disabled
Voltage
Current four-wire
transmitter
Current two-wire
transmitter
Resistance
four-conductor
Resistance
three-conductor
Thermal resistor
four-conductor
Thermal resistor
three-conductor
Thermocouples
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07
Voltage Current
4-DMU
x x x
x x
x x
x
x
x
x
x
x x
Current R-4L R-3L RTD-4L RTD-3L TC-L
2-DMU
x
x
Analog Modules
x
x
x
5-117