Siemens Simatic S7-400 - Manual (Page 322)

Analog Modules
5-106
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07
Unused Channels
Unused channels can usually be left open. Put the measuring range modules in
position “B”. You can improve the noise immunity of the module in a measuring
environment with serious interference by connecting M– and chassis ground.
Disable the “Measuring Type” parameter for unused channels. In this way you
shorten the scan time of the module.
Measuring Ranges
You set the measuring ranges by means of the measuring range modules on the
module and the “Measuring Type” parameter in STEP 7.
Table 5-63 Measuring Ranges of the SM 431; AI 16 x 13 Bit
Method Selected Measuring Range
(Type of Sensor)
Measuring Range
Module Setting
Description
U: Voltage " 1 V A You will find the digitized analog
l i S ti 5 3 1 i th
1 to 5 V
" 10 V
B
values in Section 5.3.1 in the
voltage measuring range
2DMU: Current
(two-wire transmitter) 4 to 20 mA D To supply these transmitters with
current you must connect 24 V to
the L+ and M front connector
terminals.
You will find the digitized analog
values in Section 5.3.1 in the
current measuring range
4DMU: Current
(four-wire transmitter) 4 to 20 mA
" 20 mA
C You will find the digitized analog
values in Section 5.3.1 in the
current measuring range
Default Settings
The default settings of the module in STEP 7 are “Voltage” for the measuring
method and “
"
10 V” for the measuring range. You can use this combination of
measuring method and measuring range without parameterizing the SM 431;
AI 16
13 Bit inSTEP 7.