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Hi Mike,

I'm a big fan of Microchip products, and have used several recently in various designs for various clients.

One project I'm working on is a rack mounted 6 Way power switch - basically one mains IN, and 6 individually wicthable mains outputs.

Each output has to be monitored and its power usage logged. The current draw from each output can vary anywhere from a few watts per channel up to 3000 Watts, yet the monitor needs to be reasonably accurate.

I've looked at using current sense transformers coupled to ADCs - but it's tricky because of the requirement for accurate monitoring anywhere from 3 watts to 3000 watts.

What products do Microchip offer which might be useful for this device?

Hi Kenny,

Mybe it is wise to calibrate your system to compensate for offset, drift and temperature effects. As the outputs are switchable you know when there is 0 power drawn. The ADC value is your offset error. It is always difficult to make a accurate wattmeter with such a large range. For the lower range you might want to use the kWh approach. That is; measure the power for a certain time (integration) and divide this over time. This gives a more stable power reading.

Best regards, Enrico

Mike,

Thanks for the reply - I will check out those parts.

-Kenny