Hi to All!

I have created a TIA 17 project with Simatic energy suite V17. System is running since October last year, and in general, it looks OK.

I have appr. 50 acquisition objects, some of them are 3WA and majority of them are 3VA. I am showing on trend (WinCC V7) the values of _energyBasic.actPower. I know, that this value is calculated every 10 seconds, from energy counter. Calculated values are OK (I think), but if I look them on trend, something strange is showing (shown trends are of type "staggered", to see this effect more clearly)

It looks, like the resolution of calculated power is very "poor"; if you see the black curve on trend, the average value is around 143 kW, but steps in trend are around 11 kW, and always the same, as if one digit in calculation would mean 11 kW!

Very strange and for sure not, how the power really changes through time.

The same "digit" effect can also be seen on other curves, but lower with lover average power,....

I tried to check, how this calculation is made, but I can not see in Siemens original blocks for that. 

Does anybody know, how exactly is this value calculated (_energyBasic.actPower)?

Thanks and BR!

uel123.

Hi,

did you have a look at the load management toolbox?

https://support.industry.siemens.com/cs/ww/en/view/109801603

There is a builing block for smoothing of pulse signals, this may help you.

BR

Hi!

Thanks for your answer, but problem is not filtering, but somewhere else. I am not getting energy values by pulses, but I am reading actual energy counters directly from counter, in Lreal format. And if I watch energy counter value on-line, it shows energy very precise, without obvious "steps".

This actual power is calculated every 10 seconds, as a difference in energy counter value now and before 10 seconds, divided by time. Those (equal!) steps in calculated result mean, that one "digit" in energy difference is appr. 0,03 kWh. And that is the thing, that "surprises" me. 

 And it is somehow dependent on the value of calculated power. It looks, like there is some sort of adaptive scaling inside this algorithm, but I don't know the reason. I was thinking, that this part is calculated in Lreal format (64 bit) and doesn't need scaling... .

I have already made s support request, but still waiting for (final) answer from them.

Thanks and BR!

uel123.