VISA wait on event Error -1073807313

[Wensu]

Hello, I am trying to zero and calibrate a pair of HP power meters.
After sending the command to zero one of the meters, I use the VISA Wait for RQS.vi which throws this error:

Error -1073807313 occurred at VISA Wait on Event in Wait for RQS.VI->HP 437B_visa.vi->PowerMeterSetup.vi
Possible reason(s):
VISA: (Hex 0xBFFF002F) You must be enabled for events of the specified type in order to receive them.

I opened up the "Wait for RQS.vi" to examine the "Wait on Event.vi". The "Wait on Event.vi" has the hexidecimal constant 3FFF200B (Service Request) attached to the event type input, and there is a VISA event class controller set to "Generic Event" attached to the event resource class input.
So, why the error?

Thanks,
Victor

[Wensu]

Well I still don't know what was causing my problem with the VISA "Wait on Event.vi". So I used the VISA "STB.vi" along with a short time delay within a while loop until the SRQ bit is asserted. Of course in situations when there is a failure (when SRQ is never asserted), another control is necessary to prevent an infinite loop.

[Emilie S.]

Hi Wensu:

Please have a look at the following two knowledgebases:

Enable Events

Close Event

I think what may be the problem is that you have to have a VISA Enable Event in your code before the Wait for Event.

I hope this helps you out.

Emilie S.
Applications Engineer
National Instruments

[Noel]

On NI's web site there is a tutorial, app note, and examples on using VISA for handling service requests. Below are links to each.


Tutorial: http://www.ni.com/swf/presentation/us/visa/


Application Note: http://zone.ni.com/devzone/conceptd.nsf/webmain/1A760883EEF23D7E86256DBA006C9C00?opendocument


Examples: http://sine.ni.com/apps/we/niepd_web_display.DISPLAY_EPD4?p_guid=C99424CC48EC1273E034080020E74861&p_...

[Noel]

Ooops I should preview my posts before submitting them. Here's the links in more convenient form.

Tutorial:Using Instrument Status Registers and Service Requests in LabVIEW



Application Note:Using Instrument Status Registers and Service Requests in LabVIEW



Examples:Using Instrument Status Registers with Service Requests and Polling