Clear GPIB buffer

[L_K]

Hi
One of the instruments hooked up to a GPIB board is going out of control sometime. I noticed this happens when I abort data transfering thru GPIB in the middle of communication (eg while it's still waiting). Then when I initiate communication between the GPIB and the instruments, one of the instruments is acting like it's receiving data. I guess that's the old data that's left over when I aborted the communication last time. What do you think the cause of that problem? If it's because of data left over in the buffer, how do I clear the data in the buffer? Or is there a right way to abort the GPIB communication?

Thank you

[JenK]

There is a way to clear the buffer, which I would suggest doing after you abort communication. The function is IBCLR which clears a specific device. Here is a link to the NI 488.2 Function Reference Manual:
http://digital.ni.com/manuals.nsf/websearch/35CD6168125E0EBD86256789006E84D4?OpenDocument&node=132100_US
This contains a list of all the functions and how to use them.

If you still have a problem after clearing the device repost.

JenK

[L_K]

I looked at the IBCLR manual that you gave me the link. Looks like it will work, but it doesn't say what file to #include (I am writing C code to communicate with GPIB). Here are the questions I have.

1. for the IBCLR, Do you know what file to include?
2. I look at the NI488.2 help file thru MAX. There is a function CNI4882Device::Clear(). Does it send the IBCLR as well?
3. Is it OK if I clear the GPIB buffer before I start sending commands to GPIB device? If it's OK, should I clear the buffer before initializing the GPIB device (with ibdev command) or when should I clear it?

My problem is that, there can be unexpected communication abort, so I was wondering if it's OK to clear the GPIB before sending commands to it.

Thank you

[Glenn Burnside]

This question is similar to another you posted here (http://forums.ni.com/ni/board/message?board.id=140&message.id=10349#M10349), where I have posted an answer.