This sensor is Magnetic Proximity Switch ,
active switching element is reed-switch.
Sensor is 2-wire type , connected between terminals 5 and 7
It is typical when they get older, this type of switch can give the uncertain
contact and thus cause a false pulse number
- bad contact = too low pulse number
- contact vibrating = too high pulse number
KSR Kuebler Catalog 1008....
General info in pages 3...6
Kuebler GMS 9 in page 9
http://www.ksr-usa.com/download/1008.pdf
Now how to check the inhibit signals
If there is only 5-7 connected , check only count pulses ( 6 - 7)
and 24Vdc supply (5-6)
pnp configuration is right.
the machine operator says that it always displays more counts than the actual ones
I guess bad contacts ( vibrating ) , so i would replace sensor.