Yumo E6A2-CW3C encoder from Sparkfun

[billbo911]

As mentioned in this thread from earlier this year, 2073 selected these encoders for use in our robots this year.

As a result of that post, I had a few requests to provide feedback on our experience with them. Much of the preliminary findings were reported in this post. Subsequently, Ether also asked me if I could provide some wave form captures of the output that these encoders provided. At the time, I did not have access to a DSO to capture that information.

I recently purchased a Siglent SDS1072CLM and now am able to provide the data requested.

The attached .zip file contains three files. One is a straight image of the captured wave form. (I have also attached just that .bmp file separately.) There is a .CSV file of the capture. It covers at least one full revolution of the encoder. Lastly is the actual scope's data of the capture, that is the .DAV file. If you can open it, you should be able to do quite a bit of analysis of the actual scope capture.

The version we purchased and were tested here are the 200 PPR version.
These captures were performed at approximately 1000 RPM.
The A and B signal lines were provided +5vdc through a 1Kohm resistor to each phase.

As for our experience with these encoders, we never had a single failure with them. They interfaced with the RoboRio very easily.
Are they perfect? That remains to be seen.

Here are a few caveats:
Mounting them can be a bit tricky. We found that printing custom encoder mounts that used the two M3 mounting hole made the process straight forward.
These encoders do come with a plastic coupler to compensate for a small amount of misalignment between it's shaft and the shaft driving the encoder. The lock screw holes on the coupler are very poorly manufactured and about 50% of them were stripped on arrival.
As you will see in the captured data, one phase of this particular encoder had a spot where the signal was dropped once per revolution. This may just be the one encoder I tested, or it may be a common problem. I can not say as I only tested this one encoder.
I also noticed that when I attached this encoder to an Arduino, the waveforms took on an odd shape, not as square. I was still able to track the motion of the encoder, but the signal looked a bit ugly.

If you would like me to test these in any other way, please speak up. I will have this encoder in my possession for a few more days before I return it to the team.

[Ether]

Thanks for doing this.

Originally Posted by billbo911

The attached .zip file contains three files. One is a straight image of the captured wave form.

The quadrature looks very nicely centered.

There is a .CSV file of the capture. It covers at least one full revolution of the encoder.

Why is CH2 low offset by half a volt?

Lastly is the actual scope's data of the capture, that is the .DAV file. If you can open it

open it with what app?

[billbo911]

Originally Posted by Ether

Thanks for doing this.
.....
Why is CH2 low offset by half a volt?



open it with what app?

Honestly, I will have to look into that. I did this really quickly and didn't notice. I'll post the answer in this thread once I investigate a bit further.

As for opening the .DAV file, it would require using EasyScopeX. EasyScopeX also requires the NI-VISA drivers.


You should not need the full 600MB version of NI-VESA, the runtime package should be sufficient.

EasyScopeX is available from http://www.siglent.com/ENs/prodcut-g...d=-1&tid=1&T=1
Make sure to get the version for SDS1000CML as that is the scope version that created the file.

[billbo911]

Originally Posted by billbo911

Honestly, I will have to look into that. I did this really quickly and didn't notice. I'll post the answer in this thread once I investigate a bit further.

...

Here is the key to what happened to show the ~.5vdc offset. "I did this really quickly "

When I gathered that information, I hadn't properly set up my scope. This was the first time I had used Ch.2 except for doing a low freq. cal on the probes.
So, when you don't match the probe settings (1x 10x) to the scope settings, you get odd values. After proper configuration, the new sample shows <.1 vdc, just like Ch.1, for the low portion of the signal.