Siemens SIMATIC S5-100U System Manual page 416

Function Modules
Function
The module has two isolated comparators for voltage or current measurement (selector switch with
positions U/0/I). When the preset value is reached, the LED of the respective channel lights up and
sends a "1" signal to the programmable controller.
The module must be removed or the measuring circuit disconnected before you select the function.
In switch position "0", the comparator is switched off; if scanned, a "0" signal results.
The response threshold of the comparator is set by a selector on the front panel. The selector has
scale divisions to simplify adjustment.
Installation
The comparator module is mounted on a bus unit like any other input or output module
(see chapter 3).
Wiring
See schematic diagram. Unused inputs can be left open.
Addressing
The comparator module is addressed like a 2-channel digital input module (channel "0" or "1").
Scan
(examples)
Figure 15-1. Scanning the Comparator Module
15-2
A I x . 0
O I x . 1
Channel number
Slot address
Channel "0"
Channel "1"
EWA 4NEB 812 6120-02b
S5-100U