Instrument control using GPIB

[SpeakerBoxx]

Hello all,

I am new to this Labview community and to using this software.  I have recently learned how to take readings from a Keithley 2400 instrument using their device drivers.  However, I am a bit lost when it comes to actually controlling the instrument.  Essentially I want to be able to control the power supply so that it stays within a specified range, depending on the application.  I was wondering what is the process to doing this...would I need to look at the device manual and use specific Keithley commands to write and read?  I would appreciate any input, no matter how significant.  Appreciate your time.  Thanks.

[Dennis_Knutson · Accepted solution]

There are functions in the driver from NI that control the source voltage. Look at Configure Output. There are several examples that get installed as well. Open the example finder and browse to Hardware Input & Output>Instrument Drivers>labVIEW Plug and Play. The Instrument Driver Network has links on what a driver is and how to use one.

[SpeakerBoxx]

Hello again,

I accidently clicked the solution button, I did not mean for this.  Although your advice did help, the instrument drivers do not seem to have an example, it is all for reading and displaying output values.  Even in the I/O drivers, for the "Configure" icon, this is only used to set whether the output is for voltage or current.  I am still at a loss, I would appreciate any additional help.  Thanks again.

[Dennis_Knutson]

The Configure Output has inputs for Source Mode (voltage or current), Output Level, Compliance Level, and Output Type (Immediate or Triggered). The example called Perform Limit Tests uses this function and controls the instrument and in fact does much more than just a read. The Perform Statistical Operations does control the instrument and perform a read, the Sweep and Acquire controls the instrument and then does a read. I don't understand what you are still looking for.

[SpeakerBoxx]

Hello again,

Thanks for the clarification.  My end goal is to be able to measure with the keithley a precise current reading, and from this reading I need to make the decision whether I should increase the current or voltage.  This all needs to be automated in a control system.  I ask, do you recommend that I use the PID Control toolkit for LabView, so that I can completely integrate this in one system?  Again, I am new and would greatly apperciate any insight or clarification whatsoever.  Thanks again.

[Dennis_Knutson]

I'm not all that experienced with control systems but a PID should give your better and smoother control.

[SpeakerBoxx]

Hello again,

Yeah i'm not even sure if it would require an advanced control system.  The system simply needs to monitor current within the range of uA-mA.  So it needs to maintain a very accurate reading without fluctuation.  I guess I should continue to scour the forums for similar examples.  Thanks though.