Dear DT users/instructors,
I would like to clarify about electrical energy calculation in DT. I have connected voltage and current sensor to the data logger. I would like to calculate the energy consumed. I read the example in the DT manual. In that example, at interval of 20sec, integration (IB) function is used to calculate the energy.

Using this method, it is calculating the are under a straight line. My question is, what would be the case if, say at 10th second the power goes up and come down around 18th sec. Isn't that this high power is ignored? Is there a better way to know the energy used, with current and voltage input to DT (I mean using calculation and not external energy meter)?

Your assistance is appreciated.

TQ [Chandran]

You can increase voltage and current acquisition frequency. If your electrical signal has a dynamic with a frequency component higher than the double of DT80 acq. frequency you will lose detail as your example shows. Just yesterday I programmed a DT80 for energy meters acquisition; looking at the spec. I found that the measurement cycle of the meter is 40 ms allowing reasonable energy calculation in common industrial application.

Regards.

Thank you for the reply Teo. I am afraid that will overload the DT. Besides this, the DT also does many other logging function and reporting etc. Other than increasing the sampling frequency, is there any other way to do it?

TQ [Chandran]

I don't think so. Anyhow I would speed up the logger up to 1 s or 0,5 s schedule rate without any concern for the logger, maybe this can be enough for your application.

Good morning Chandran,

The highest priority is given to the logging of data (That is after all our primary roll) and the other things like web pages, data transfer etc run in the back ground
The back ground actions will slow down as the sample speed increases. How much depends on how fast the schedule is running and how many channels you are sampling. If you are reading 2 or 3 channels at 2 Hz then there should be enough for the other processes.
The only way to really know is to try it.

Cheers,
Roger

I come to understand that this is the correct way of calculating energy used. So, I will play around with the timings to that I get an optimum one. Tq for all your supports.

Good Luck.
Chandran