what is the difference between GPIB and VISA when we compile a program?

[Dennis_Knutson]

Well, all of your earlier statements about sending IDN? can be ignored since the instrument doesn't support the command and that was just time wasted. I'm now confused as to where you are issuing the commands and how. What program are you actually using to communicate to the instrument in MAX? There are three different ones.

And I assumed the instrument was old because my first search of the SR web site did not turn up any reference to an SR245.

[Dennis_Knutson]

I'm at work now with a working GPIB board so I can provide a picture of the NI-488.2 communicator screen. You will notice three different buttons - Query, Write, and Read. Do not click the query button for any commands that do not have a '?' in them. A query will do an ibwrt of that command and then do an ibrd. You do not enter the text 'ibwrt' or 'ibrd'. If the command does not have a '?', then the instrument will not return any data and the query will timeout. Depending on how you set the instrument up, even doing a proper query (i.e. '?1') may also return a timeout. For example, it the instrument does not get triggered, it will not acquire a signal so there wouldn't be any data to return.

Also, can you try to reattach the VI you've modified. Instead of attaching the VI, attach the whole llb because that would include all of the subVIs as well.

Message Edited by Dennis Knutson on 09-20-2006 07:37 AM

[Linghui]

When I hit the menu of communicating with instrument, I saw the diaglog window like what you pasted

I followed what you said. If a command contains ?, I send query. If the comand doesn't contain ?, I wrote the comand first and then read it. The results are the same, "EABO". Nothing changes.

For example:

I wrote a command I1, and read it. The window showed "EABO". I1 means to designate the first 1 anolog port as input, the remainder become outputs.

Second example:

I queried a command ?1, which showed"iberr=EABO". ?1 means to return the value of the designated analog port.

Thank you, Dennis

[Dennis_Knutson]

Well, when you send the command 'I1", why are you trying to do a read? You will never get a response back from the instrument because the instrument is not commanded to return data. The instrument should accept the command and perform it but that is all. If it doesn't, then there is a problem with basic communication and not just with reading. Is there anything on the instrument itself that you can confirm that the command has been executed? Front panel display, any indicator at all that the instrument is even listening?

[Linghui]

When I complied a sample program use GPIB command write and read.  We can't get any data. The error window poped up:

Error occurred at GPIB Read in Yu_001.vi

Possible reason(s):

Labview Generic file I/O Error

NI-488:I/O operation aborted

I pasted this program and you may help me look at it.

Thanks 

[Linghui]

When I send any commands from Communicator. what I got is "iberr:=EABO". There are two light indicator in the front panel of SR 245. One is Activity Green LED and Error Red LED. I can't see any light blinking when  commands were operated. I bet there were no response.

When I turn on the power supply of Boxcar, the Activity LED and Red LED blink one time.

When I ran the program that I pasted, the LEDs blink one time.

Thanks

[Dennis_Knutson]

I don't know. You could try sending 'I8;MA:' (notice semi-colon on the end) and changing the gpib write mode to 3 and gpib read mode to 0. That's what the driver has. I'm not sure that trying to write a LabVIEW driver will succeed until you can get the same thing to work in the 488 communicator though. It would be nice if the instrument had some visual feedback that the commands (i.e. I8) are actually being accepted.

[Linghui]

I tried again.

When  I wrote command, and hit the Write botton,  I do see Activity Green Light blinking quickly. I also tried other words(for example my name) by hitting Write botton. I also saw the Green Light blinking. Maybe any word may let Activity light blink.

When I send command like ?1, or ?D, What I got for string Received is "iberr=EABO"

Thanks

[Dennis_Knutson]

Yeah, that doesn't sound too promising. I'm not sure where to go from here. No one else has chimed into this trhread that may have experience with the actual instrument and I'm down to just guessing. Maybe it's time you asked Standford Research for help. The may not have much experience with LabVIEW but I would think that using MAX would be something fairly common.

[AnalogKid2DigitalMan]

Just a stab-

Is EOS configured properly for the instrument? My only experience with SRS was over 10 years ago, it was a DS345, I had no problems communicating over GPIB.