Siemens S5-135U/155U System Manual page 430

Analog Input/Output Modules
Setting the Data
When using the 4 to 20 mA inputs, you can select data representation of 0 to
Format for the 4 to
1023 bits or 256 to 1279 bits by pressing the appropriate switch. You can
20 mA Range choose different data formats for all four input channels.
When the voltage or 0 to 20 mA inputs are used, the relevant switches remain
at the opposite settings.
Labeling of the switch on the module cover:
1) It is advisable to mark the selected switch setting in these fields.
Connecting Transducers are connected to the analog input module via shielded cables of
Transducers
up to 200 m in length. When they are laid separately from power system
cables, distances of up to 500 m are possible.
An arbitrary mixture of voltage sensor, current sensor, two-wire and
four-wire transducers can be connected. For two-wire transducers, there are
four short-circuit protected supply terminals at the front connector.
Caution
!
To use two-wire transducers, the reference potential (common input) of these
channels must be connected to L-. This defeats the isolation between the
channels and the supply voltage L+/L-.
Note that the bus interface of the module is activated with 24 V via enable
lines F+ and F- at the front connector.
9-48
range 4...20 mA
0...1023
range 4...20 mA
256...1279
otherranges
0...1023
channel 0
channel 1
channel 2
channel 3
1)
channel 3
channel 2
channel 1
channel 0
System Manual
C79000-G8576-C199-06