VISA close function in serial communications problem.

[lsimpson]

I have been successfully communicating with an Agilent E3631A power supply over the RS-232 serial communications. The only error I run into is when I close the VISA session, using the VISA close subVI I get a framing error on the power supply. Is there something that is sent over the serial communications line when a VISA Close subVI is run that would cause an error on the attached equipment?

L. Simpson

[Justin_E]

Hey Laura,

Is the framing error returned from the VISA Close function? If so, is there an error code associated with it? Framing errors are usually caused by a difference in the serial settings of your two device, so I'd try and verify that all of the serial settings are the same between devices.

We actually supply an instrument driver for this device, found here : http://sine.ni.com/apps/utf8/niid_web_display.model_page?p_model_id=231
The instrument driver's Close function simply calls the VISA Close function, so there isn't anything special that needs to be done for this device besides just calling the VISA Close. Even if there is something sent over the communication line, it shouldn't cause any errors on the attached equipment. The problem might be with the setup of the instrument or of the serial port you're using

[lsimpson]

I have good communication with the current settings between the two devices and I am able to send and receive data between the two devices. When the VISA close function is issued I get error code 511 on the device (E3631A), but the LabVIEW vi closes without error. The communications is done over RS-232.

My head scratcher here is why the VISA close function specifically is causing an error, when all other VISA communications are not?

[Albert.Geven]

Is a break issued when close is called or a zero character sent like in this thread:

http://forums.ni.com/ni/board/message?board.id=170&message.id=402303&requireLogin=False

try to use a comport monitor