How do I capture the quadrature encoder Z-index pulse using 6035E DAQ card?

[IANES]

Hi,

Currently, I'm using 6035E to measure the angular position of servo motor.
I'm able to read the counts from Channel A and Channel B.

From the technical note which I downloaded from this website, I understand that the Ch A and Ch B should be connected to pin 37(PFI8/CTR0 SRC) and pin 16(P0.6) of I/O connector, respectively.

However, it doesn't indicate any solution of capturing the Z-index pulse.
I'm wondering whether I can read the pulse by connecting to pin 3 (PFI9/CTR0 GATE).

In fact, I have tried it out and it worked. I can see the counter is counting from the MAX.

The problem is I don't know which VI I suppose to use.

I don't know how to program it in LabVIEW.

If this is not the right, what are the alternatives?

Please enlighten me. Thanks.

Best regards,
IANES

[DJ_L.]

Hey IANES,
I am assuming you are using LabVIEW 7.1 and the most recent NI-DAQ driver 7.3.1 or so. Also I am going to assume that you are using the DAQmx VI's. You need to select the "Create Channel.VI", and then left click underneath of it and choose the following: Counter Input -> Position -> and then the type of Encoder that you are using. Then you also need to use the DAQmx Timing.VI and the DAQmx Read.VI to do what you want. Take a look at the Example Programs that you can access by using the Help -> Find Examples, and search for the Examples that use counters. Also, I have attached a small VI with the Create Channel.VI in it with the Z-Index options set up for it. Hope this helps. Good luck with your application.

DJ Loberg
Applications Engineer
National Instruments

[IANES]

Thank you for your helping.

In fact, I've tried it out before. However, it seems like the device doesn't support the VI you suggested.

I dumped the DAQ assistant.VI into the block diagram and select the desired type of encoder. The message under the Supported Physical Channel is 'No supported devices found'.

If I run the program, the pop-up window is shown (Pic[3]).

Is it the problem can be solved?


Please find the attached files.

Thanks.


Regards,
IANES

[IANES]

One more thing is you didn't mention which I/O connector pin supposed to connect the Z-index pulse?

Or it is not necessary of the connection. It's purely done by the program?

Thanks.


Regards,
IANES

[Stuart_G]

E Series Devices don't really support the Z index of quadrature encoders by default. That is why you are getting the error in DAQmx. Normally, to do a quadrature encoder measurement you would want to use a TIO device or a new M series board. I found the following article on the NI website which describes how you might use an E series device and some of the limitations. There also were a few other articles which seemed to have info that you might want to search for.

http://zone.ni.com/devzone/devzoneweb.nsf/Opendoc?openagent&36BD71244BB26FC886256869005E541B

StuartG