6221/2182 simultaneous Delta & voltage measurement

[Katrina90]

Hi,

My hardware & software setup is as follows.

1. I am performing a delta mode measurement which works fine on its own. 6221 I-source is connected to my laptop via GPIB, 6221 & 2182A communicate via trigger link cable and RS-232. (code 6221_2182A_delta-mode-measurement)

2. I also want to perform a voltage measurement (read voltage only to measure the Seebeck coefficient) with the Nanovoltmeter 2182A directly. So I am connecting the GPIB cable to the device and need to turn on GPIB on the front panel. (code: 2182AC_senseDCvoltage) This code on its own also works.

The problem occurs when I try to put both measurements in a sequence in Labview. Executing the first frame with the DC voltage measurement is fine while it gives an error (VISA: (Hex 0xBFFF0015) Timeout expired before operation completed) when it tries to start the delta measurement (code: 6221_2182A_integrated)

I assume it is because I am connecting 2182A via GPIB while it is trying to communicate via RS-232 with the current source.

Any suggestions how I can work around this? E.g. is there a way of turning the GPIB off and on in Labview while executing a specific frame in a sequence if this is indeed the problem?

Best,

Katrina

[RTSLVU]

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@Katrina90 wrote:

The problem occurs when I try to put both measurements in a sequence in Labview.

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Well I haven't looked at your code yet but I can say if you are using a Sequence structure you are probably doing it wrong. Honestly there is no  well very little good use for a Sequence structure. You should not really need or use them any more unless for some reason you need to force execution order and your VI's don't have an error cluster.

Okay now that I have seen it, I can't unsee it...

Lose the "Express VI's" and "Instrument Assistant" those things are made for those little 4 hour LabVIEW Seminars sales pitches to show how fast you can "just throw something together" but as you are beginning to see they are not useful for any "real programs". 

Sorry you are going to have to do it "the hard way" if you want to do it right. 

[Katrina90]

RTSLUV,

Not sure whether this answers my question. Are you saying that I should eliminate the sequence and replace the instrument assistants with the instrument drivers? Do you expect that this will solve my problem with the GPIB communication? Can I configure this explicitely in the instrument drivers?

[Katrina90]

I have now put a Labview file together based on 6221 and 2182 library examples which use KE instrument drivers only without any sequence.

The first half of the code (2182 voltage measurement) works only if I set the KE2182A to GPIB "ON" on its frontpanel which confuses me for one since it should not matter if it communicates via VISA, right?

The second half (6221 delta mode measurement) gives an error at the KE622X-Config instrument driver. The 6221 delta mode measurement runs on its own when RS-232 is turned "ON".

Any help is appreciated

Many thanks

[Katrina90]

So apparently you can really only use one interface at a time and you have to select the interface at the front panel, i.e. selecting GPIB disables RS-232 and vice versa.

I have solved my problem now by communicating with the 2182 Nanovoltmeter through the 6221 current source via RS-232 with the following commands:

SYST:COMM:SER:SEND

and

SYST:COMM:SER:ENT?

[laihaier83]

So simple. I will try it on my own VI. Thanks a lot.