I'm road testing the Keithley Bench Digital Multimeter DMM6500. In this post, I investigate how to use the external trigger to start a measurement.
In this post, everything is configured and executed in LabVIEW. In the previous post I used the front panel. |
Goal: I want to measure the voltage on a microcontroller GPIO pin just after it is set to high.
Check out the last post for the details.
Set Up the External Trigger with LabVIEW
I'm using the SCPI :TRIGger:LOAD "LogicTrigger" command to set up the trigger model.
That one can be used to configure the external input.
The string I pass to the SCPI call is: 7, 7, 1, 0, "triggerbuff".
parameters:
- 7: the external trigger in as active digital input
- 7: not used. It enables the external trigger out.
- 1: make one measurement
- 0: no delay after trigger
- "triggerbuff": I created a custom buffer to capture the measurement for this exercise. You can also use one of the 2 standard buffers.
edit: this approach sets the meter up to trigger on the falling edged of the external trigger in. That's not what I want.
I had to add a block to reconfigure to the rising edge.
Here's the addition. The LabVIEW project attached to this post is updated.
I think I found an error in that Keithley LabVIEW Configure Event Input block.
I logged a topic on the instrument's forum: https://forum.tek.com/viewtopic.php?f=617&t=141442
Run the LabVIEW Flow
In this short video you can see the meter display updating in real time when I execute the Trigger Template block in LabVIEW:
This is the form used to execute the LabVIEW flow:
The flow itself - the trigger part of it - is shown at the top of this post.
I adapted the existing Keithley example Keithley DMM6500 DAQ6500 Series Measuring DCV With High Accuracy DCV.
If you want to view the whole flow, I've attached it to this post.
