Encoder position not being detected by counter

[N.Pierce]

Hi,

I am having trouble getting labview to detect the angular position of a 3-channel, X1 encoder (only counting leading edges of pulses) using a NI 6221 card and SCB-68 connector block.

I have connected a CRO to the encoder signals to ensure that there is no noise and am getting very clean signals.

The encoder is wired up as follows:

'Z' channel - PFI 9 (Pin 3 on connector block)

'A' channel - PFI 8 (Pin 37 on connector block)

'B' channel - PFI 10 (Pin 45 on connector block)

The Encoder voltage and GND are coming from pins 8 and 9 respectively.

The output from the counter counts from 0 - 360 degrees over the course of one second and then holds at 360 degrees. Changing the motor speed has no effect on the output, it counts to 360 in one second regardless of motor speed.

I suspect that there is some very basic configuration error I have made, being a simple mechanical engineer and all.

I have attached a screenshot of the configuration of the counter.

Thanks in advance for any assistance.

Nick Pierce

[S_Hong]

Hi Nick,

It seems like you have connected your encoder correctly to the right terminals. However, I believe your problem might be with your external clock connections. Could you also explain why you have connected channel Z (PFI 9) as your external clock for you acquisition? I believe that you should select another PFI line and send in an external clock to sample your data.

Have you also checked the signals coming off of the encoder to make sure that it is operating properly and that you have the proper channels?

I hope this helps,