Problem with master/slaved agilent 6031 dc power supplies thru Labview

[Kenrose]

Hi, I have 2 Agilent 6031s connected in parallel with a master/slave config.  The slave is controlled by an analog signal provided by the master, which is controlled with GPIB thru Labview.  I'd like to be able to read the current from the slave supply using GPIB but this is causing problems - the Agilent manual says it can be read in this configuration.  Some troubleshooting has shown the following:

- supplies operated manually from the panel work in this config and the master controls slave and they both output current

- when gpib is used to control and read the master ONLY, the config works and the slave outputs current just like manual operation above

- if I initialize the master and slave supply using gpib  and control the master through it, then the slave supply does not output current and the amperage display reads "OL".

Has anyone run into this problem or got this to work?  Am I missing something obvious?

[nyc_(is_out_of_here)]

If you want help, you had better provide a link to the relevant programming manual, as I don't have the time to search for it.

[cstorey]

I don't think they are truly Master/Slave and I think the GPIB address setup is probably your problem here. See this reference page 85 - https://literature.cdn.keysight.com/litweb/pdf/5959-3342.pdf?id=1000000383-1:epsg:man

A direct supply is connected to the PC via GPIB cable and that supply has a unique GPIB address.  Then you can connect other supplies to the direct supply via a serial-link cable.  Linked supplies get their Primary GPIB address from the direct supply but must have a unique Secondary GPIB address. 

So your code will have to use the Secondary GPIB address to read voltage from the linked supplies.

Are you using VISA?   I've never had a reason to use secondary GPIB addressing in LabVIEW + VISA.  I believe the format for the VISA resource is "GPIB[board]::GPIB primary address[::GPIB secondary address][::INSTR]" and you would need to open references to both instruments and query each separately as follows..

Hope that helps.

Craig

[Kenrose]

hi Craig, thanks for the reply - I figured out what the problem was. I am using the config described on page 67 of the manual ("Auto-parallel operation") and a vi library for controlling the 6031 that came from HP originally, but now comes from Agilent.  This configuration works fine as a master-slave, provided you get all dip switches set correctly, and use Initialize and Output On/Off from the 6031 library on both supplies before reading them - I was missing the Output On/Off vi for the slave supply - once added the whole arrangement worked nicely.