Siemens Simatic S7-400 - Manual (Page 321)

Analog Modules
5-105
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07
5.21.2 Measuring Methods and Measuring Ranges of the SM 431;
AI 16
13 Bit
Measuring Methods
You can set the following measuring methods for the input channels:
• Voltage measurement
• Current 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 of 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 5-62 Selection of the Measuring Method for Channel n and Channel n+1 of the SM
431; AI 16 13 Bit
Meas. Type
Channel n+1
Meas. Type
Channel n
Disabled Voltage
" 1 V
Voltage
1 to 5 V
Voltage
" 10 V
Current
4-DMU
Current
2-DMU
Disabled x x x x x x
Voltage " 1 V x x
Voltage 1 to 5 V x x x
Voltage
"
10 V x x x
Current four-wire
transmitter x x
Current two-wire
transmitter x x
Example
If you select “current (two-wire transmitter)” for channel 6, you can only disable the
measuring method or set “current (two-wire transmitter)” for channel 7.