GPIB Analyzer and Keithley 2001+7001

[Blokk]

Hello,

I have an old system consisting of an old PC with DOS, and via an ISA GPIB card connected to a Keithley 2001 DVM and a Keithley 7001 Multiplexer (card1: 40CHs 2 poles relay and card2: 10CHs 4 poles relay are in it). A software is running under DOS what measures voltages and resistances with the DVM via the 2 poles relay, and prec. resistances via the 4 poles relay. The source code is not available.

We have bought LabView2010full, and a PCI GPIB+ Analyzer card.  I have started to Analyze the communication in this system by MAX.

What I would like to do, is to "clone" the old system's MUX and measurement pattern, and do the same in LabView. Mostly I understand what I see in the captured GPIB communication, for example these lines:

          --  --  --     UNT UNL UNT LA27 TA1
          --  --  --     :SCAN (@2!1,2!3,2!5). END
          --  --  --     UNL UNT LA27 TA1
          --  --  --     :TRIG:COUN 3. END
          --  --  --     UNL UNT LA28 TA1
          --  --  --     :ROUT:SCAN:EXT:FUNC (@1:3),'FRES'. END
          --  --  --     UNL UNT LA28 TA1
          --  --  --     :TRIG:COUN 3. END
          --  --  --     UNL UNT LA28 TA1
          --  --  --     :ROUT:SCAN:LSEL EXT. END
          --  --  --     UNL UNT LA28 TA1
          --  --  --     :TRAC:FEED:CONT NEXT. END
          --  --  --     UNL UNT LA28 TA1
          --  --  --     :TRAC:CLE. END
          --  --  --     UNL UNT LA28 TA1
          --  --  --     :TRAC:FEED:CONT NEXT. END
          --  --  --     UNL UNT LA28 TA1
          --  --  --     :STAT:MEAS:COND?. END
          --  --  --     UNL UNT TA28
          --  --  --     0. END
          --  --  --     UNT UNL UNT LA28 TA1
          --  --  --     :INIT. END
          --  --  --     UNL UNT LA28 TA1
          --  --  --     :STAT:OPER:TRIG:COND?. END
          --  --  --     UNL UNT TA28
          --  --  --     2. END
          --  --  --     UNT UNL UNT LA27 TA1
          --  --  --     :INIT. END
          --  --  --     UNL UNT LA28 TA1
          --  --  --     :STAT:OPER:COND?. END
          --  --  --     UNL UNT TA28
          --  --  --     0. END
          --  --  --     UNT UNL UNT LA28 TA1
          --  --  --     :STAT:OPER:COND?. END
          --  --  --     UNL UNT TA28
          --  --  --     16. END

The multiplexer (GPIB address is 27) is commanded to use its 2!1 , 2!3 and 2!5 channels for 4 wire resistance measurement, and the DVM (GPIB address is 28) performes these measurements. These 4 wire resistance measurements takes a while, so the PC is continously checking wheather they are finished yet or not by repeating the four last lines.

My problem is, why the "16" decimal values is there? Actually when the DVM finishes this particular measurement, the answer for the question 

STAT:OPER:COND?

becomes 1024. Regarding to the Keithley manual (keithley manual), on page 329, on figure 4-24, the 16 is not an answer for the stat:oper:cond. The 1024 is okey, it means that the DVM is Idle. But 16 is not a valid value. Anyway, I understand that, this means that the device is still busy with the previous measurement, but why 16? Regarding to the manual, the number should be 512 instead of 16...

I am new to GPIB, if somebody could explane this discrepancy to me, It would be nice...A more simple manual would be even better, the Keithley manual's GPIB part is not really handy...

Thanks very much!

ps.: I have attached the exported capture file from the GPIB comm.

[Blokk · Accepted solution]

okey, I think i am on the right trail finally...If somebody gets in a similar situation (have to deal with gpib at the first time), I advice to see a simple example program:

like this:

http://www.keithley.com/base_download?dassetid=11901

It really helps a lot, to understand the basic principles in GPIB comm, when you have to deal with a DVM and a MUX at the same time..

regards

[Tatjana Daudrich]

Dear Blokk,

i post found some interesting Links, may be you are interested in.

GPIB Messages

http://zone.ni.com/devzone/cda/tut/p/id/3389

GPIB Driver Versions for Microsoft Windows and DOS

http://zone.ni.com/devzone/cda/tut/p/id/5326

Additional you will find much more informations by looking for "GPIB" in search-window on www.ni.com

Could I help you with this information oder do you need more?

Best wishes,

Tatjana

[Blokk]

Thanks very much!