Jaguar Encoder issuse

Well first of all we upgraded to the MDL-BDC v. 101 that was released recently on all of our jaguars. We have 4 of them and we are using CAN to drive, the issue is that 3 out of 4 jaguars are not receiving any encoder input when debugging using MDL-BDC Comm. Jaguars 1,3, and 4 are Black, Jaguar 2 (the one that works) is Grey. Now, the encoder that worked on Jaguar 2 was plugged in on Jaguars 1,3 and 4 and it worked fine. However the encoders on Jaguars 1,3, 4 were plugged in on Jaguar 2 and it did not work. We know the wires are proper and the encoders are working perfectly because we ran continuity tests on all the wires as well as used an oscilloscope to test the encoder signals, so we know the encoders, their mounts and their wiring is all proper. Not to mention we know the 3 black jags are capable of reading the inputs because we tested using the proven working encoder. Does anyone have any idea why the other 3 encoders are not working? Are we doing something wrong? Thank You!

Are the encoders the same?

Did you double-check the nonfunctioning encoders with the oscilloscope after you determined that none of the Jaguars would read them?

We checked them multiple times with the scope as a result of them being unreadable. The waveforms looked correct (both channels were clearly in quadrature and reacting correcting to wheel rotation in both direction) and the waveforms looked clean, sharp rises and falls in the correct voltage range. We swapped them out with a similar but different optical encoder module and the Jaguars started responding, I have not had a chance to 'scope out the newly working encoders to see how the waveform compared. I’m hoping an opportunity will present itself to bring in my DSO and capture the working and non-working signals for later analysis, but given that we’re in the heat of build season, I don’t see that happening unfortunately.

Though I have to admit, I’m really very curious as to why the Jaguars could not read the signal, so I will be trying to get back to it.


Let me ask a basic question: how did you determine the encoders are not working using the BDC-COMM tool? If you are referring to the position or the speed values in the modes tab being at 0 and not moving, then did you set the Encoder Lines in the Configuration tab? Without setting the Encoder lines, the Jaguar will not be able to report the position nor speed.

We drove the wheels in speed control, voltage control and even spinning by hand, and we did have the encoder lines setting correctly set. The problem was resolved by replacing the encoders with a different model, as of yet we have not determined precisely why the older encoders did not work, as I checked them on the oscilloscope and they were most definitely feeding the correct signal in to the Jaguar. We also re-used the wiring harness when we switched the encoders, in addition to beeping them out with the multimeters, so we know the wiring is/was always intact. This one is a mystery…


Tejas spot on ;), we can pretty much declare this a [FIXED] Thread in that case, anyone reading this please use the E4P-360-250-D-H-D-B encoders, not the E4P-250-250-D-D-D-B encoders, they seem to have issues. Good luck to everyone!

If I’m reading the new US Digital part numbers correctly, the difference between the “D” and “H” in those part numbers is the plastic cover. The “H” part cover has a hole in the middle. I doubt that explains the problem the Jaguars had trying to read them.

I agree with you that the difference in parts should have no effect, I suspect there is an underlying fault with the encoders we had (they were used in the past quite roughly) and I just have not had the chance to thoroughly examine the signal generated. I believe our problem was related to the encoders being partially nonfunctional in a not very apparent way.