I'll try to make this quick because I'm typing on my phone but we have several ENZ1D-495 rotary encoders and haven't been able to find much info online about them but we need to test them and determine which ones are good or bad.

I don't have complete access to a scope but did try one yesterday and couldn't get any response from channel b however a probe may have been bad and I forgot to check that, or maybe I had the probes grounded wrong as I had them grounded to various objects and only got a good response when I grounded them to the encoders power supply ground.

So how do I test these properly, what should be connected where as far as a scope goes and what settings might I need to change?

 

Are these common quadrature encoders?
These can have low signal sine wave or TTL square wave output.
The TTL can be single ended A - B & Z or differential (RS420) with the A,B Z in complement.
Obviously first you need to identify the type and the connections to each.
After powering you should see the relevent TTL or sine signals WRT common on the respective ABZ leads when slowly turning the shaft.
A & B are the quadrature, 90° pulses WRT each other, and the Z is a once/rev marker signal.
The sine wave output usually use an arc-tangent function to increase the natural pulse count.
You can also do it with a VOM meter if turning very slowly.
Max.