Example Code

Synchronizing Two DMMs with an External Trigger

Code and Documents


This virtual instrument (VI) synchronizes two National Instruments digital multimeters (DMMs). The same transistor-transistor logic (TTL) trigger needs to be connected to the front connector of each DMM or passed through the PXI trigger lines, and this TTL trigger initiates acquisitions on both DMMs at the same time. Since the onboard clocks on each of the DMMs are not shared or phase-locked, this synchronization is not a true hardware synchronization. However, the LabVIEW code configures both DMMs for the same measurement parameters so both DMMs will operate with the same functionality as long as they are the same model. A star configuration for the triggering is recommended, but a daisy chain configuration also works. Make sure that both DMMs have been initiated and are waiting on the trigger before the trigger is sent.

Example code from the Example Code Exchange in the NI Community is licensed with the MIT license.