Trying to get US Digital encoders to work

Our electrical plate is almost finished, and now we are trying to get our encoders to work, so we can test some features in the programming. However, we could not get the encoders to work on the robot. The encoders are showing lights, but we cannot see anything on the dashboard.
We tried switching cables and DSCs, but with no success.
We connected an encoder from another robot to the same elctronic system and it worked. We know that they are from different model. The encoders on the robot were E4P-360-250-D-D-D-B, and the one we tried on the old robot was E4P-360-250-D-D-H-B. One didn’t work, one did.
Any help? I don’t know if it matters, but we are programming with java.

The encoders have a specific frequency limit. You have to choose the encoder wheel that matches your rotational speed. If you are looking for too great a resolution at too high a speed, the encoder produces no output. I have also heard that there were some encoders that were shipped this year from the manufacturer that may have a defective component. I don’t have that information at hand but perhaps someone else will post on that issue.