Problems about reading out values from Keithley 2000 while using external triggers in Labview7.1

[st7]

I am doing my thesis about setting up the complete system to measure the IV-characteristics of solar cells.I use Keithley 2000 to measure the voltage across the solar cell and the shunt resistor(in order to get the current value through the solar cell).I use the Microprocessor to generate the external trigger signals and other things.Moreover,I use Labview7.1 to realize the combination of High Level Labview and the hardware system. In my system,I want to measure more points in the IV-curve.Therefore,I use the buffer of Keithley 2000.I want to send many external triggers and use the multi-read SubVi to read out all the data in the buffer.Now the problem is I can manage the external triggers and Keithley does do the measurements when there is a trigger.But I can't read out any data from Keithley by using multi-read SubVi.When I choose immediate triggers,it works fine.So I wonder what the problem is.I find there are several parameters in Configuration Trigger SubVi,but I can't fully understand what should I adjust in my case.
I'm looking forward to hear some suggestions.
Thanks very much!

[JorisV]

Hi,

Have you checked the manual already of the Keithley device itself?

Check the link below:

http://courses.ece.uiuc.edu/ece445/documents/manuals/k2000_userguide.pdf#search='keithley%202000%20manual'

Control source and event detection
The control source holds up operation until the programmed event occurs and is detected. The
control sources are described as follows:
• Immediate — With this control source, event detection is immediately satisfied allowing
operation to continue.
• External — Event detection is satisfied for any of three conditions:
• An input trigger via the Trigger Link line EXT TRIG is received.
• A bus trigger (GET or *TRG) is received.
• The front panel TRIG key is pressed. (The Model 2000 must be taken out of remote
before it will respond to the TRIG key. Use the LOCAL key or send LOCAL 716 over
the bus.)

I guess you are using the Instrument driver from our website, if not you can download it from our website:

http://sine.ni.com/apps/we/niid_web_display.download_page?p_id_guid=E3B19B3E90B0659CE034080020E74861

Use the multi-read example from the is Instrument driver and check how you have to setup the trigger by checking the manual of the Keithley DMM itself. We just provide a way to command and configure the device. The actual functionality of the instrument is inside the manual.

Regards.

JorisV
NI BE

[st7]

Thanks for your reply.
I have read the user manual and knew how to use the external triggers through different methods. However, Labview still can not read out the data in the buffer.
Does NI.com have any example which use Labview to control keithley2000 with external triggers?

Thanks in advance!

Chun

[JorisV]

Hi,

There are no examples available on our website for the Keithley 2000 instrument with an external trigger. We cannot test it because we do not have the device. You can ask Keithley support if they have an example available. I don't really think that this is a LabVIEW problem but more a question about how to use triggers with the Keithley DMM. So giving Keithley a call would be a good thing to do.

The only vi I've found was for a single-shot coming from an immediate trigger. The only thing that you maybe forgot is the Init_trigger and set it to continuous?

Regards.

JorisV
TL AE
NIBE