I am working on some applications which use TRIAC phase control or missing cycle method to control the output power to the load. I have tried to use data logger to acquire the voltage and current of the load, however according to this question about the fastest rate to acquire one channel, it can only read 67 or 112 reading per second (15ms or 9ms).

For TRIAC missing cycle control method, at 50Hz, I think I need to acquire the data at least twice faster than 10ms to have a reasonable accurate result. For phase control method, I think the require rate would be even much higher.

So, I would like to ask how can I measure the power/current for a TRIAC control loading?

Thank you.

Hi,

I did a similar test but I used an oscilloscope: 1000 points (depending on the desired resolution), no persistence, no delay (trig started on the left of the screen), trig on LINE synchro, set time base on 1 cycle (50Hz, 20ms span). In this example, I have 1000 points per cycle (0.36 degrees resolution) and one cycle per acquisition at 50 Hz. For more LINE cycles, I used more Oscilloscope memory, adjust the time base for the resolution per cycle .

I do not know your configuration, but this example is not in real time acquisition, we have death time between acquisitions. Tested on vb.net 2015 and LAN connection on my oscilloscope, I had 55 ms between two acquisitions for an on LINE cycle (20 ms), a total of 550 ms for 10 cycles. But I used more memory, for example 10,000 samples and a duration of 200 ms, and I had a total acquisition time of only 91 ms for 10 cycles.

Do you need a fast acquisition because you want to analyze quickly? Otherwise, you may be able to take several samples with your 34972A and average them. The result will be in function at the missing cycle or at the phase angle method if you have suffisant and constant number of sample between results.

I hope these informations may help you.

Regards

Yves