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Hi,

I am currently writing some software in a uC in order to keep track of several S0 outputs of kWh meters (S0 according to EN 43864).

My question is the following:
Almost all suppliers define a pulswidth of > 30ms. So the maximum amount of pulses per second will be around 30 (1000ms/30ms). Let's assume a meter with 1000 impulses/kWh = 1 impulse/Wh.

Now the maximum I can measure in 1 minute will be 30 impulses * 1 Wh/impulse = 30Wh. This equals to 30Wh*60 minutes = 1800W

So if I connect a load of 1800W to my meter, it will generate 30 impulses/minute. What happens to the pulses if I connect a larger load? I understand the number of pulses will go up, but how about the pulsewidth of the S0 output? When each puls is 30ms, it is not possible to measure more than a load of about 1800W.....

Can anybody help me out?

Frank

A load of 1800W generates 1800 pulses per hour, since 1800W for the duration of 1 hour = 1800 Wh.
So you get a pulse every 3600/1800 = 2 seconds.

So where's the problem? I think you mixed seconds and minutes somewhere...

Robert

Hi Robert,

Thanks for your prompt reply. I knew something was wrong, but not that it was that stupid......[xx(]

This is obviously the sign that I need some sleep.

Thanks again for your reply.

Frank