Problem with DMM PXI-4070

[Tarasik]

Hello everyone. The simple measurement. (Single measurement AC Voltage). Why the DMM takes so much computer resources? 52% of the CPU.

And when run DMM Soft Front Panel CPU is not more than 2%.

I use the example from NI examples folder. What is wrong?

Measure AC Volts.vi Thanks

[Ton Plomp]

Hello everyone. The simple measurement. (Single measurement AC Voltage). Why the DMM takes so much computer resources? 52% of the CPU.

And when run DMM Soft Front Panel CPU is not more than 2%.

I use the example from NI examples folder. What is wrong?

Add a wait of 100 ms to the while loop.

Be glad you have a dual core, on a single core this would take 100%

Ton

[texasaggie97]

Hello everyone. The simple measurement. (Single measurement AC Voltage). Why the DMM takes so much computer resources? 52% of the CPU.

And when run DMM Soft Front Panel CPU is not more than 2%.

I use the example from NI examples folder. What is wrong?

The reason it using so much CPU is because it is restarting the HW and then doing a busy wait while waiting for the point to be available from the hardware.

Instead of starting from Measure AC Voltage, I started from Cont Acq & Chart Multiple Samples. This will only start the device once (niDMM Initiate) and then uses niDMM Fetch Multi Point to get the points from the device. What I added was niDMM Read Status in the loop. If there is no point available (backlog == 0), wait a few ms. If there is a point, go fetch it.

[Tarasik]

Add a wait of 100 ms to the while loop.

Of course I tried, it has no effect

Instead of starting from Measure AC Voltage, I started from Cont Acq & Chart Multiple Samples. This will only start the device once (niDMM Initiate) and then uses niDMM Fetch Multi Point to get the points from the device. What I added was niDMM Read Status in the loop. If there is no point available (backlog == 0), wait a few ms. If there is a point, go fetch it.

Thank you so much! It's works perfect