linear encoder count doubles going reverse than forward

[Famus]

Hi,

I have a quadrature linear encoder. I hooked it up with a PCI-MIO-16E-4 (aka PCI-6040E) according to the tutorial. Forward motion works great. But reverse motion have decrementation twice as much as it should. I have it hook as: A to PFI8, B to DIO6 and using counter 0. Can anyone please tell me what is wrong? Thanks alot!

Famus

[Hillman]

Hi Famus

Using quadrature encoder with PCI (i.e. not cDAQ) use connect Channel A to the source input of counter x (coutner 0) which is PFI8 as you said.

However, for B, you need to connect to the up/down line - im not sure if its DIO6. But check your connections and make sure you set the counter for simple edge counting and set the active edge to falling.

link - about your set up - maybe its vibrations?

Please reply soon,

Regards 

[Corby_B]

Hello Famus,

Thanks for your post!

I would like to ask if you are using digital lines 0-5 while also trying to use your encoder on line 6? If this is the case there might be a setting you will have to change to make this work correctly. Its not the same exact behavior but take a look at the following knowledge base that talks about this issue.

Using the Open Digital Lines on an E-Series DAQ Board when Taking Encoder Measurements

Let us know if any of this information helps you with your problem!

Cheers!

Corby_B

http://www.ni.com/support