How to Control the Sample Time for UMI 7764

[Medal_Jeff]

Hi everyone,

I am using a UMI-7764 along with NI MAX to connect encoders to LabVIEW. My LabVIEW program measures the position of the encoder, the following error, and the primary feedback position. We are not using a DAQ to obtain the data.

I am running into a problem where the sample time is around 6 samples/s. My goal is to make the sample time ~60 samples/s. How would I go about doing that?

In addition, when I write the data to a file, the data does not seem to be matching. For example, the primary feedback position and the position of the encoder do not subtract to the following error displayed in the file.

I have attached my VI for your reference, along with a photo of the error in my data that I had previously described.

[davidraj]

Hi Jeff, 

Can you give me a bit more information about your setup? 

Are you sending the econder signals just into the analog input? In that case, why aren't you just using a simple DAQ analog input? Are you using the encoder signals for motion applications? 

As per the frequency of the signal, if you're getting just 6 samples per second it sounds like you have a software limitation. Have you run the code with a normal while loop (as opposed to a timed loop) with highlight execution to see where the limitations are? 

Lastly, I couldn't see the driver API you were using with the device, you just said it wasn't with DAQmx. Have you had this version of your code working at any point before? 

Thanks, 

David Raji