Keithley 237 and LabVIEW Drivers - Read Measurement.vi Issue

[ddkevan]

Hi,

I am having some trouble getting my Keithley 237 SMU to function properly with my copy of LabVIEW 2013. I have found drivers for the SMU on both Keithley's website and LabVIEW's website. They appear to be the same .llb driver bundle. My SMU is communicating with my PC (windows 8) via a GPIB card.

To the problem:

When setting a voltage and reading a current, on occasion the program will cease operating. I am unable to stop it manually and have to hard restart LabVIEW. At first I noticed the problem while attempting to run a custom built ramping VI, but I was able to replicate it using the DC voltage example 1 vi in the driver bundle, if I try to run the program repeatedly too quickly. If I insert wait periods into my repeating program, or wait before running the DC example, it seems to reduce the frequency of freezes, but not completely removes it. In any case, the wait time needed seems to be over a second or two, which is unacceptable as a solution for my application.

Upon playing with the programs, I noticed that if I remove the "Read Measurement" Subvi from my program, It executed flawlessly, with zero wait time inserted. So it would seem the problem would be somewhere within this subvi.

I don't have the proficiency or skill with the 237's language input. I was wondering if there had been any changes or updates to fix this hanging bug, or if you might be able to guide me in ways to fix it.


Thanks so much!!

[Dale C]

I am not certain about this but, it looks likea and GPIB communication(write or read) is left to default mode of 0.
This means append EOI for each communication.
I would replace each write or read with a LF and EOI.
This is simple mode = 2.
You will find this on each write or read in the right hand side of the write and read vi.
Simply right click on the mode terminal and creat a constant. Set the constant to the number 2.
See if that helps.

[ddkevan]

Hi Dale,

Thanks for your quick reply.

I am a little uncertain about your advice.

by "write or read" do you mean the "receive message.vi" and "send message.vi" subvis? I see these in the "Read measurement.vi".

On these, on the left hand side, I see a "read mode" and a "write mode" terminal, respectively.

I will set these to 2 and see if this works.

[Dale C]

Yes. That is what I mean.

[ddkevan]

Hi Dale,

I have just tried this, first setting all of the read and write subvi's mode to 2 in the read measurement vi. This didn't appreciably change the results of running my program.

Then I tried setting all instances of the read and write subvis in all the relevant vis. Also no change. Any other thoughts on this?

[ddkevan]

Hi Dale,

I'm not sure if this will help to diagnose further, but I have enabled the "Highlight execution" feature once the program hangs. Attached is an image of what I see. Each time so far it seems to be hanging on the specific version of "send message.vi" seen in the image with the green arrow overlaid. To the right is an image of this sub vi also with "highlight execution" enabled.

I should note that the image I posted doesn't have your fix displayed in it. But I have ran it with the addition of the 2 constant, with no change.

I will continue to poke at this, and would love to hear from you if you have any further insight

[StefanThie]

Different story same device.

I am looking for a running labview version of the pulse voltage sweep program. All versions 6,7, and so on…, give me in the “pulse time not met” error and if I am using the current pulse version (LabVIEW 6i (LV) Example to perform Linear Stair Pulse and Current Sweep with 236, 237 or 238)then it is working, but it is the current who is pulsed. Any ideas

Stefan