Programing Instrument Assistant with Keithley 236 SMU

[Tenn8705]

Hi,

  I am trying to program a Keithley SMU to Instrument assistant in Labview. However, I do not know what commands to issue. The manual has codes, but everytime I put a different one in for the command..... I get the same token value. Can someone instruct me on how to sync the SMU to the Instrument assistant? Thank you.

[Dennis_Knutson]

Why are you trying to use the Instrument I/O Assistant instead of the driver?

[Tenn8705]

Because my P.I. wants the SMU to run in unison with this temperature program as opposed to after another. He said it would be benificial to use Instrument assistant to help with that. He already used Instrument Assistant to convert the temp program (fairly easy), now I need to do the same but with the SMU (a lot harder). This is my first project. I don't know anything about programing. I've read the manuals, but things just don't seem to work out as noted in my first post.

[Dennis_Knutson]

I have no idea what a P.I. is but he obviously does not know much about LabVIEW or programming either. A driver is merely a set of VIs and no different than the Instrument I/O Assistant. The big difference is that someone has already written the code to communicate to the instrument instead of you reinventing the wheel with the assistant. If you are just beginning, it makes absolutely no sense to not use the driver. The driver would be much better suited to running in parallel with some other bit of code.

[Tenn8705]

I completely understand. I already have the driver..... is there anyway to run that driver for the SMU in unison with the Instrument Assistant Temperature Program that I made? As opposed to one after another (sequentially). Also, lets say I had no choice but to try and rewrite that SMU program using Instrument assistant (My Boss really wants me to do it)...... Do you have a step by step method of doing so? Once again, I want to remind you that I don't have any programing experience. I don't know how to start this and I could really use your help. Thanks.

[Dennis_Knutson]

Whether you can run in parallel will depend on the type of interface you are using (RS-232, GPIB, etc.) and will be no different with the driver functions or the Instrument I/O Assistant. The Instrument Assistant is just a crude form of a real driver (imo). The underlying code generated by the assistant is going to be pretty similar to what is in the driver - just less flexible and efficient. In fact, it seems to me that the instrument I/O assistant would tend to force you to sequential operation if you try to cram all functions into the assistant and that's a bad design.

Aside from the help window in the Assistant, I can't provide much assistance in using it. Your first step would be to fully understand the instrument and the programming manual. Before writing any code, test the commands and look at the responses in a program like Hyperterminal. that should give you a better idea of the sequence of events that you need to do in the assistant.

[Tenn8705]

The interface I am using is GPIB. How would I set up the block diagram to allow both programs to run in parallel?

[Dennis_Knutson]

GPIB does not have the ability to operate in parallel. For the most part, you can only communicate to one instrument at a time. If you place the code modules in parallel like any other parallel operation in LabVIEW, you will still end up doing the writes and reads sequentially - this is managed by the GPIB driver. If you need synchronization, then you need to provide some details on the instruments, and the code you have written. That is one of the problems with the Instrument I/O Assistant. So much is often wrapped up in this big ugly module that it's difficult to control. The smaller, more specific functions in an instrument driver are easier to use.