Pilz PSSu K F INC - Manual (Page 14)

Function description
Operating Manual PSSu K F INC
1001688­EN­06 14
C+
G
L
C-
a b c d e
B+
B-
A+
A-
Legend:
} a: The counter counts backwards because the signal at channel A is lagging.
} b: The module has received a zero pulse. Provided the function is activated, the
counter value is copied into the latch memory with a rising edge at input C+.
} c: The counter counts forwards because the signal at channel A is leading.
} d: The module has received a latch pulse. Provided the function is activated, the
counter value is copied into the latch memory with a rising edge at input L.
} e: The counter is disabled because there is a 1 signal at input G.
4.1.4 Counter operating mode
"Counter" operating mode is not recommended for safety functions because pulses can be
generated if there are any track errors. Compare errors can arise as a result, which can
lead to a shutdown or to common cause errors.
In "Counter" operating mode, the module's dual­pole, differential inputs A, B, C have the fol­
lowing functions:
} Input A (Count)
Input A is the input for the encoder's counter pulses. The module counts each rising
edge.
} Input B (Up/down)
At a 0 signal the module counts forwards. At a 1 signal the module counts backwards.
} Input C (Gate/Latch)
The counter is stopped with a 1 signal. The module ignores the counter pulses at the in­
put until a 0 signal returns.