GPIB USB HS- syncronize Bus

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Hi Rasheel

Thanks for your reply.  Of cource I don't want to Initiate two DMM simultaneously.  I want to start measurement  when trig DMM externaly. I use same signal for both DMM and trigger measurement using Ext Tirig event. But wave forms have time dilay. How to solve this broblem. Please see attachment. The other problem is If triggring sequence change an error occured, example, TBUF expected command heder or Memory Empty. The Read memory VI provided by NI  can use with TARM SGL only. Please help me.

Wije

[Sputnikrent]

Hi Wije,

What do you mean the waveforms have a time delay? If your DMMs are waiting for the external trigger, they should both start acquiring data when the trigger starts. I'm not sure if you could change anything in LabVIEW to solve that.

I would advise speaking with the manufacturers of your DMM to see how that can be solved.

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Hi Rashell

It is not a problem with DMM. I read so many papers they syncronzed two DMM using other programming lanuages. Although the DMMs trig with extenal signal the trig evevnts vi not syncronized. When programme run DMM1 take reading with external trig and after finish then start 2nd DMM. It cannot happen since both DMM trig with same signal. Thats mean this delay happen from programe eventhough they trig with externally. Please check labview vi arrangement sent with last email. I nortised that the external triggering vi run one by one. Thats why waveforms got time delay. In this situation we have to modify this programe to start two external trig commannds or vi at same time. How to do that?. But still I am not sure the USB GPIB can syncronize two event.

Best Regards

Wije

[Sputnikrent]

Hi Wije,

Why don't you try running your VI in Highlight Execution mode so that you can see exactly how the program is flowing? You can do this by clicking on the lightbulb icon on the toolbar at the top.

You might also want to have your program flow sequentially instead of in parallel. The GPIB bus cannot send commands simultaneously anyway. Why don't you try alternating the VIs using the error out, so you have:

DMM1 trig event vi >> DMM2 trig event vi >> DMM1 HP-3458 sample >> DMM2 HP-3458 sample >> DMM1 arm trig >> DMM2 arm trig.

Or any variation of the above.