Support for Old Vibrating Sample Magnetometers

Question

Hello.
I am a relative newcomer to LabView and I am trying to get some support for a few older Vibrating Sample Magnetometers (VSM) on behalf of my employer.  These machines are quite old and, although they have GPIB connectivity, I am having difficulty in being able to control them using LabView.  Although they use the IEEE-488 GPIB standard, they were built before the introduction of the Standard Commands for Programmable Instruments (SCPI), rather than the newer 488.2 standard.  As such, they work with their own proprietary commands, which are proving impossible to find.  I have a working LabView program that was written by a university student for a master's degree in physics.  However, I cannot communicate with the individual components, such as the gaussmeter, power supply, etc, using measurement and automation explorer.  They don't even respond to an "*IDN?" query without timing out, which I thought was standard.  I have tried lengthening the timeout time and tried to use drivers for similar instruments.  My question to anyone out there is, do you have the drivers or the programming manual for any of the components listed below?  The Vibrating Sample Magnetometers were built by the now defunct DMS/ADE.  The current owners of DMS/ADE can offer little support for such old equipment.  Likewise, is there something else I can try in lieu of these drivers and commands? 
Devices:  1.) DMS Model 1660 VSM, 2.) DMS/ADE VSM Model 4, which includes the DMS/ADE model 32KP gaussmeter with its own GPIB port.
Thank you for your time,
Liam

Answer 1

Hi Liam,
As per GPIB 488.2, as I already mentioned, the ibEOSchar under Ibconfig is an 8 bit value so it will take value from 0 to 255 for which 3 number width is sufficient. Measurement and Automation Explorer also works in the same way. EOS byte value under Termination Settings section of GPIB settings accepts a decimal number from 0 to 255 and it will not allow any character and also value more than 255 as its field is limited to 3 numbers and even if you enter a value more than 255, it will be automatically changes to 255.
So, As per 488.2, You cannot give both carriage return and linefeed characters together and you cannot use the same in MAX also.
Try framing your entire command with EOS as per built in LabVIEW carriage return and linefeed functions and use GPIB Write.vi to send this entire frame. It may work.
Also, I would like to see your VSM's communication manual and understand how these commands have been implemented.
Coming to IBEOS command, its easily understandable and its used to Configure the end-of-string (EOS) termination mode or character. It have low byte and high byte.
Low byte is always an 8 bit EOS character and high byte can take three forms which are A, B and C. Also High byte can have values with combination of A,B or C.
For Example, ibeos (ud, 0x140A); means, Configure the software to end reads on newline character (hex 0A) for the unit descriptor. Here high byte is a combination of A and C where as low byte is the HEX equivalent of ASCII Line feed character.
Regards,
Naresh Narra