GE Versapro counter ?

Okay, so I was on line today doing some troubleshooting with a 90-30. the Program has a rung with an up counter in it. there is a contact on the rung tied to a proximity switch for motor shaft. While the shaft is moving the switch is transitioning about every second and the counter is counting this. I noticed that looking at the data watch table for the prox.input and counter, the input shows a constant 1 and the counter keeps counting in the table. I physically looked at the prox. switch and the led on the prox. is flashing about every second. I am assuming that this is just a matter of the program not showing the data quick enough in the table to uopdate it so it looks like it is always on. Just wondering because the counter is supposed to increment when the enable switches from off to on and so on. Also, has anyone ever heard of a memory location wearing out and the data sometimes getting erroneous. Thanks

What you see is a screen update "thing", watch long enough and you will likely see it go off once-in-a-while. When a memory location "wears out" you will get a a parity error and likely will need to replace the device with the "bad" memory.