GPIB commands need leading space character

[KLP]

I am having an issue with SCPI commands requiring a leading space when talking to a particular instrument. However, the problem looks to be related to the PC and not the instrument. I am using an ADEK PC with Windows XP and I am using the NI Measurement and Automation Explorer as the communication tool. The instrument is a Standford Instruments SR530 AMP. As an example, to do a reset of this instrument I send it a “Z”. I can see the instrument activity light flash but the instrument does not reset. Through trial and error I found that if I put a leading space in “ Z” the command works and this is true for all of the other commands used for that instrument. Since this worked on previous systems I have built I decided to try an HP Z210 PC and that worked as expected…. No leading space necessary. To take other software out of the equation I reloaded the PC with just Windows XP and the GPIB software and the problem is still there. I have tried another GPIB card and got the same results. I also tried communicating with other instruments and they do not require the leading space so I think my issue is a combination of the PC data formatting and the instrument itself. But I need to correct it on the PC end. I have 10 of these systems in the field and I can’t change the existing code so adding a leading space character to the commands is not an option. Any ideas how my PC could be affecting the data format enough to cause this issue? I have looked at the PC Bios set up options and nothing jumps out. Same with the GPIB card setup.

[Dennis_Knutson]

I don't think I agree with your conclusions about the pc. If there was a problem with the pc or GPIB settings, I would imagine that you would see it with the other instruments. Since you only have the issue with the one instrument, I would focus on that.

p.s. A 'Z' to the stanford instrument is not at all a SCPI command.

[crossrulz]

Are you using different versions of GPIB cards?  I've seen some strange interactions between certain versions of GPIB cards and particular instruments.