Simultaneous data collection on two or three HP34401A digital multimeters

[lauriers]

Hello,

I'm trying to use two (and if this works three) digital multimeters (HP34401A) at the same time. I've made a VI file that manages to do this if I want 500 samples with a manual delay of 50ms between them.  Requesting 600 (or more) samples at the same time (for the same manual delay) seems however not possible. What happens is that the first multimeter starts sampling while the second one waits, to start only after the first multimeter has finished measuring. It would be great if someone could help me to solve this frustrating issue.

Thanks,
Steven

[Dennis_Knutson]

How are you triggering the meters? Is it a shared hardware trigger or are you issuing a GET? Those are the best methods and the second meter will not wait for the first to acquire. In fact, the second meter really doesn't know or care about the first meter being there. After the trigger is generated, you would then poll each to see if the measurement is complete before reading the data from each. Are you just using the functions provided in the driver? If you are, they are not at all appropriate for what you are trying to do.

p.s. You posted to the forum for DMMs made by NI. You should post to the instrument control forum in the future.