NI 7350 encoder problem

[AndyN]

I have 7350 PXI motion controller running under Labview 7.1. I am having problems reading encoders on my motors. I have 8 channels but only one works. I can switch wires to that channel and that way I tested that encoders are OK. Hooking up to other channels does not work. MAX shows zero counts or it varies +-1. Encoders are single ended quadrature encoders.

I think I set up everything the same way in MAX for each encoder. 

1. How should I configure switches on SCB 68?

2. Are there any special steps I need to make in order to use it?

3. What about self calibration. Does it have anything to do with it?

4. Are there anyt switches/ fuses on 7350 that I should consider?

[SMeserve]

Hi Andy,

Is there a reason you are using a DAQ breakout board with a motion card?  I'm unsure if this could cause your issues, but perhaps.

[AndyN]

I can say that I inherited it that way. It was working fine in the past.  I guess you would suggest UMI? What would that give me?

The problem is not solved but somehow fixed. I used channels 1-4 and it works now. I have no idea why channels 2-3 don't.

[SMeserve]

Have channels 2 and 3 ever worked?  IT is possible it is a hardware issue.

[AndyN]

I know channel 3 was OK in the past.  I think you might me right but I am fairly new to those things so I put blame first on me.

[JeffL]

If you're using the SCB-68, you can ensure that the switches are in Feedthrough mode (http://www.ni.com/pdf/manuals/371745c.pdf, page 5).

Also, can you check the pinouts on the cable itself (at the connection point when it goes into the motion board?).

[AndyN]

I did set it up as feedthrough. The cable is original from NI. I checked the resistance between the ground and the voltage output on the motion card - it is very small like 20 ohms...

[SMeserve]

Hi Andy,

Which cable do you have?