How to test an optical encoder in the field??? 1

[funguy123]

If I have an industrial 24VDC incremental optical encoder with A and B channels in the field (say a dynapar/danaher encoder), how can I verify that it is working properly? Do I use an oscope and connect to the A and B channels to check that they are properly 90 degrees out of phase?

Anything I can do with a voltmeter?

Any specifics would be a great help.

Thanks,

gschmelt

 

[itsmoked]

Scope is the best bet fore-shore.
Meters are hard to interpret.

It is pretty hard for the two signals to lose their 90 degree-ness because of the construction. However they can get strange when the optical sensors get dirty or start to fail or the bearings start wearing out. The scope should show any problems.

 

[funguy123]

Itsmoked,

Thanks again!

So power up the encoder and connect to the A and B channels with a 2 channel scope? Haven't done this before.

Thanks,

Gschmelt

 

[itsmoked]

Essentially, yes.

Check this link for a little education.

http://www.feedbackdevices.com/uploadedFiles/Products/DynaparEncoderCatalog.pdf

Make sure you understand what the output should be for your encoder. Differential or quadrature etc. Marker signals etc.

Hopefully you can find a/the common then hook up your two scope channels to the outputs.

Others who work with these frequently, might have more ideas.

 

[machmech]

Hello itsmoked


Looks like to me on the encoder signals can be
checked w/meter which has a frequency function
this confirms the signals are transmitted hence
encoder is good then input reference points and
check for accuracy if movement not accurate one
might assume dirty signal via loose connection
or interference from noise, I suppose checking
movement drive for worn or loose parts which
could cause backlash is a given.

Would this conclude trouble shooting for this
operation just a guess at best on my part I have
no experience with this but may need this knowledge
soon.

Sincerely, Chuck

 

[funguy123]

Thanks itsmoked and machmech. I am using an oscope to look at the A and B channels as well as \A and \B. Looks good.

I appreciate the help!

 

[MikeHalloran]

If there are two channels, say X and Y, and they use the same encoder model, you can physically swap the encoders and see if the problem follows.



Mike Halloran
Pembroke Pines, FL, USA