Counter (0 -> 1 / 1 -> 0) - Siemens Sirius 3RK3 System Manual

6.7.8.3 Counter (0 -> 1 / 1 -> 0)
Description
Note
The count value is not stored. At the start of safety mode, all counters begin with their initial
values.
The safety relay supports the counter function "Counter (0 → 1 / 1 → 0)". The counter value is
only changed when there is a positive and negative edge. The current counter value can be
counted up or down via one proprietary counter input each. When a parameterizable counter
limit value is achieved or overshot, the function output Q is set.
The counter function has:
● 3 inputs: CU - Counter input up, CD - Counter input down, R - Reset
● A function output Q for the result of logic operation (RLO)
Functional principle
● The counter value is increased by 1 with every positive and negative edge at the
"Counter input up", except when the counter value reaches the maximum value 65535.
● The counter value is decreased by 1 with every positive and negative edge at the
"Counter input down", except when the counter value reaches the value 0.
● The counter value remains unchanged when there is a positive edge simultaneously at
both counter inputs.
Modular Safety System 3RK3
System Manual, 10/2008, 926 2530-02 DS 02
Description of the software
6.7 Functions
191