E8801A Instrument I/O Assistant Queries with SCPI commands not working sometimes

[Frostwing]

I'm using an Agilent E8801a PNA Series Network Analyzer. When I use the Instrument I/O assistant in labview to attempt to talk to it things go fine when I query things like *IDN? and *STB? but when I use other SCPI commands like CALC:MARK:STAT? I get this error: 

Invalid separator - The parser was expecting a separator and encountered an

illegal character. For example, the semicolon was omitted after a program

message unit.

followed by an error saying that the quest was unterminated. (Which i assume is caused by the first error)

It's highly confusing because all three commands were taken directly from the programming manual. Any suggestions on why all of my commands (and I do mean all) with colons in them are giving me these two errors?

[Dennis_Knutson]

My first question to you is why you are even using the Instrument I/O Assistant when there is a driver already written for it? At the very least, you should get the driver and look at the syntax in there if you want to reinvent it.

[Frostwing]

Well the only communication method I really know about is serial and GPIB and this time I've got this USB to GPIB converter and I can't just use the GPIB Read/Write blocks that I'm accustomed to 😕 If you think the driver would help could you point me in the direction of it? Truth be told everything I've ever written I've done 100% from scratch until this project.

[Dennis_Knutson]

What is wrong with the link I gave you. A link is meant to be clicked on so that is all that you have to do.

Your statement that you cannot use the GPIB functions because you have a USB-GPIB is just plain silly. Of course you can use them but it's even sillier to be using the low level GPIB functions anyway. You should be using VISA functions for everything and of course that is what the driver uses.

If any of your past projects involved instrument communication and you did not even try to find an existing driver, you spend a considerable amount of time recreating the wheel.

[Frostwing]

Sorry, it was very late when I made that reply. I followed that link this morning and all of the drivers there crash on launch when they try to initialize visa. I get an error that says: AGPNA Initialize -  Serial Port Not Supported. Which is bizarre because I'm using USB to GPIB. So I'm really not sure what I'm doing wrong. It seems like most drivers I've tried to use have had similar problems and looking at the block diagram didn't help much either 😕 for some reason the commands it was sending to the PNA have all these %.; things in it which I'm not sure what do. I've never had to add a bunch of %.; strings to my code in the past.

Also, I've found a Prologix GPIB Sample vi that lets me send strings over VISA to my device. Once again things like *IDN? and *STB? are working but things like CALC:MARK ON are not working and I'm getting that error again from the first post.

Message Edited by Frostwing on 08-27-2009 11:09 AM

[Dennis_Knutson]

I suspect that by 'crash' you are simply getting an error. What do you have the VISA Resource Name control set to? Did you click on the arrow and select your instrument from the list.

The % is not being sent. I think you are looking at the string format commands. These are basic LabVIEW functions on the string palette (i.e. Format Into String) and if you've never used these either, you might want to look at the LabVIEW tutorials and look at the LabVIEW help.

What does Prologix have to do with this? Is that what you are calling the USB-GPIB converter?

[Frostwing]

Yeah, I'm getting that serial error. I've used the string formatting stuff before. I've just never seen a %.; command before. I believe prologix is the manufacturer of the converter. And yeah I've been setting it to the proper com channel (Com 3 in this case) I just still don't understand why it'll respond properly to *IDN? and *STB? but not CALC:MARK:STAT? all three of which are from the programming manual. Are these different types of commands or something? 😕

[Dennis_Knutson]

Okay, all along I thought you were using a proper USB-GPIB converter. I don't have a very high opinion of the Prologix. I think it is for hobbyists and not serious work. You would need to do considerable work to adapt the instrument driver code. Sorry, can't help.

[Frostwing]

😞 ok ._.

[Mr.F]

 This USB-GPIB device appears as a COM port? Does the Prologix USB-GPIB show up in Measurement and Automation Explorer? If so, does it show as a GPIB card or a COM port?