Siemens Simatic S7-400 - Manual (Page 313)

Analog Modules
5-97
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07
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 and 6/7, as shown in the following table:
Table 5-58 Selection of the Measuring Method for Channel n and Channel n+1 of the SM 431; AI 8 14
Bit (6ES7 431-1KF20-0AB0)
Meas. Type
Channel n+1
Meas. Type Chan-
nel n
Disabled Voltage
" 1 V
Voltage
1 to 5 V Voltage
" 10 V
Current
4-DMU
Current
2-DMU
R-4L
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
Resistance
four-conductor 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.
Circuit for Resistance Measurement
The following conditions apply when measuring the resistance with the SM 431;
AI 8 x 14 Bit:
Table 5-59 Channels for Resistance Measurement of the SM 431; AI 8 14 Bit (6ES7431-1KF20-0AB0)
Measuring Type Parameter Permissible
for Channel n
Condition
Resistor
(four-conductor terminal) 0, 2, 4 or 6 You must disable the ( “Measuring Type” parameter for
channels n+1 (1, 3, 5, 7).
The reason The connections of channel n+1 are used
to supply the resistance that is connected to
channel n.