error-1073807265 occurred at VISA GPIB Control REN in HP34401A

[puffy]

I'm experimenting with instrument control using Labview. I have function generator and multimeter connected. And I used HP34401A Initialize.vi->HP34001A Getting Started.vi to model the multimeter. When I ran it, it stopped at the multimeter and an error message as below popped up:
"Error - 1073807265 occurred at VISA GPIB Control REN in HP34401A control Mode.vi -> HP34401A Initialize.vi -> HP34401A Getting Started.vi -> "filename.vi"
Possible reason(s):

VISA: (Hex 0xBFFF005F) No listeners condition is detected (both NRFD and NDAC are deasserted)."

What exactly are NRFD and NDAC?
Thanks.
puffy

[Dennis_Knutson]

NFRD is Not Ready for Data and NDAC is Not Data Accepted. These are handshake lines on the GPIB bus. NFRD indicates that an instrument is ready to receive a message and NDAC indicates whether an instrument has accepted a message. You say you are using the HP34401A to model the multimeter. Does that mean you have a different model connected? If you do have the correct model connected, did you select the VISA Resource Name to match what is actually detected by MAX or did you leave it as the default. If you right click on the VISA Resource Name arrow, you will get a list of all valid names.

[puffy]

---

@Dennis Knutson wrote:
NFRD is Not Ready for Data and NDAC is Not Data Accepted. These are handshake lines on the GPIB bus. NFRD indicates that an instrument is ready to receive a message and NDAC indicates whether an instrument has accepted a message. You say you are using the HP34401A to model the multimeter. Does that mean you have a different model connected? If you do have the correct model connected, did you select the VISA Resource Name to match what is actually detected by MAX or did you leave it as the default. If you right click on the VISA Resource Name arrow, you will get a list of all valid names.

---

Hi,
Thanks for the prompt reply. Sorry about the confusion. I meant I used the HP34401A Getting Started.vi to model. But my multimeter is actually 34401A too. And when I ran the vi individually it works fine meaning that my Labview communicates with the multimeter fine. But when I ran this in my program which measures the AC voltage in a loop, the error message pops up saying "Error -1073807265 occurred at VISA GPIB Control REN in HP34401A Control Mode.vi->HP34401A Initialize.vi->HP34401A Getting Started.vi->filename.vi". As you said before, no data is received. Can you suggest any solutions? I can't find the VISA resource name. But I'm sure the model is compatible to the multimeter. Thanks.
puffy

[Dennis_Knutson]

When you tried the Getting Started example, did you have to change the GPIB address on the front panel? If you did, then you'll have to wire a constant to the Address/Port input of this VI. I'm sorry about the confusion on the VISA Resource Name. This example converts the front panel numeric Address/Port to a resource name. Also, if you're running this VI in a loop, you may need to slow things down in order to give the instrument time to respond. I don't like using "Getting Started" examples in a loop anyway. They tend to be pretty slow because they do everything (initialize, reset, configure, read) and usually what you want to do in a loop is just get a reading. You might want to look at the App Example. There you will see the separate functions. Putting the Read Meas in the loop would be what I would do.