06-14-2018 11:56 AM - edited 06-14-2018 11:57 AM
I am using Labview 13 to create an automated system that measures the voltage of multiple pressure transducers (at the same time) at various pressure values. I have: PXIe-8102 embedded controller
NI PXI-4065 DMM
NI PXIe-2527 Multiplexer
The pressure controllers I am using are connected through GPIB and communicated with through GPIB commands. (Mensor 8201, DHI PPC3)
I want to trigger the voltage measurements of the UUTs with a signal from the pressure controller saying it has changed pressure values, take measurements of the UUTs, wait until pressure controller has changed values and then get triggered to take another measurement and so on...
My understanding is that I can use NI SWITCH and NI DMM using handshaking to take measurements of multiple channels and parse these measurements to assign them each to their respective channels for display. However, I'm not sure how to use the GPIB to trigger the measurement.
I'm fairly new to LabView so I'd love to know if I am on the right track.
06-15-2018 03:34 PM
What does your data look like? Is each measurement just a single voltage point? If so, the "trigger" can just that your application sent a command over GPIB to the pressure controller, verifies controller updated, and tell the DMM to take a measurement.
06-18-2018 07:03 AM
Thanks for your help! Each measurement is a single voltage, one from each UUT, before the controller changes the pressure.
To make that the trigger, would I use a software source trigger? More specifically, how would I attribute that the controller has been verified as a trigger for the DMM? The niDMM Send Software Trigger sends a command to trigger the DMM. The niDMM Configure Trigger VI configures the DMM to wait until the niDMM Send Software Trigger VI is called before triggering the DMM. How do I set the command to be used for triggering?
06-18-2018 11:32 AM
I have not used the NI PXI-4065 DMM, but if it works similar to any other multi-meter I've used, I would just let it acquire data in the background (separate loop in LabVIEW). Then change the pressure, wait some amount of time, and then ask the DMM for the most recent data. The time to wait would depend on your sample rate and how long it takes for a pressure change to effect your system.