tlink triggered visa measurement with keithley 2400/2000

[mischi_miyagi]

Hi,
I'm having the following problem with the attached VI: I want to do a voltage sweep with the keithley 2400 and measuer current with it. Simultaneously I want to measure the resistance of piezoresistors with the keithley 2000 triggered over a TLINK-cable. That works fine but only when I'm running the VI in the highlight mode, running it normally the SRQ of the multimeter (keithley 2000) gets an timeout error. Increasing the timeout doesn't solve the problem. Also I played with syncronous and asyncronous write and read but also this didn't solve my problem. Since the measurements working fine seperately I guess it's my labview programming... ;(
Any suggestions???

Mike

[Dennis_Knutson]

While you have good dataflow between each function for the separate instruments, you have no dataflow between them and the dmm is probably getting setup before the other instrument. Running with exection highlighting turned on changes the execution order. A basic principle of LabVIEW is that functions with no dataflow connections between them will be run in parallel. I'm not sure where the dataflow has to change as I'm not that familiar with the instruments but there are a couple of options. You could place some of the code in a sequence structure (though I generally dislike this, it is a valid use in this case) and wire the error out connections from both instruments to it. A Merge Errors function could also accomplish the same thing.

[mischi_miyagi]

Hi,
thx for the answer...but sequencing doesn't solve my problem...I think I have a different problem:
I modified the VI in that way that I'm reading the status bit for "buffer full", if it's set then I read the buffer, and there I saw that the multimeter doesn't set this bit. But when I run both instruments seperately (or together but not triggered) it works, so, I think something with the triggering is wrong, it seem that the multimeter is waiting for trigger although it measured the desired amount of data....just makes me crazy...but I don't give up hope...

Mike

[mischi_miyagi]

Hi, me again...
I noticed something else: When I say the multimeter has only 16 numbers, it works...

Greets,
Mike

[mischi_miyagi]

Hi,
could it be the problem that I'm writing simultaneously to the gpib? As far as I read thing about this shouldn't be a problem, but who knows...

Mike

[mischi_miyagi]

OK, it seems that my triggering is not working properly...have to contact keithley I think...

Greets,
Mike

[mischi_miyagi]

Well,
I did it, now it works fine, it was mainly a trigger timing problem....so, please find attached the fully functioning basic program. I hope this helps other people...

PS: How can I change the thread title to "tlink..."- DONE ???

Greets,
Mike