I am using LV to construct a GPIB instrument. It will listen and respond when addressed but never be the CIC.
The code so far is based on the vi at http://www.ni.com/example/28508/en/ (.png file attached, I think that will work). My codes is on a stand-alone computer and I don't want to re-write it, so I will use the example code and describe mine.
Note the VISA Wait On Event configured for a GPIB listen event. The first time I run the vi, the Wait On Event times out if I don't send anything from the CIC, as expected. If I send something, Wait On Event succeed, VISA Read reads the message I am sending from the other computer, then VISA Write sends the response. Good so far.
However, on the next loop the VISA Wait On Event should time out if not addressed - it does not time out, it plows on through as if another listen event has occurred. VISA Read errors out.
I have several GPIB status reads in place for troubleshooting. On a correct cycle, LACS and TACS are active when you would expect. At the beginning of the next loop, LACS and TACS are cleared. There is no Listen even present on the second loop.
I have the remote CIC set to Unaddress the instrument after reads and writes. If I don't do that, LACS stays up after the Listen event. The CIC has to actively unlisten the instrument. That is the only way I have found around this.
Is this a VISA issue or a NI-488.2 issue or a hardware issue?
TIA
Ed K