Siemens S5-135U/155U Setting the Data Format for the 4 to 20 mA Range, Connecting Transducers

Analog Input/Output Modules

Setting the Data Format for the 4 to 20 mA Range

When using the 4 to 20 mA inputs, you can select data representation of 0 to 1023 bits or 256 to 1279 bits by pressing the appropriate switch. You can 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:

	channel 0
range 4...20 mA	channel 1
0...1023	channel 2
	channel 3
	1)
range 4...20 mA	channel 3
	channel 2
256...1279
otherranges	channel 1
0...1023	channel 0

1) It is advisable to mark the selected switch setting in these fields.

Connecting Transducers

!

Transducers are connected to the analog input module via shielded cables of 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	System Manual
	C79000-G8576-C199-06