STM CircleOS forum / Energy meter

romario · 2011-12-12 11:10:50

One of the students is trying to build an enegy meter using one of the analog meter IC's like ADe7756 05 ADE7755. We have been having difficulties in selecting the best interface for the meter between a microprocessor and a microcontroller. The programming language is C which should be able to handle complex algorithms for load load rescheduling etc. Is the STM32 capable of accomplishing this project? How many energy meters can be connected simultaneously to the STM32?

STPrime · 2011-12-13 17:48:25

Hello, I have not used the ADE77xx meter IC's. From looking at the spec sheet, it looks like you will need some kind of voltage translations if you are going to connect it to the ADC of the STM32. The ADC inputs are 3.3V.

For the frequency measurements, you should be able to connect it directly to any of the PWM ports and do an input capture to measure the frequency. In your code you would use the calculations in the data sheet to figure out the active and instantaneous power. You can try the example programs found in the STM32F_Lib. There is one for input capture.

You can directly hook up as many ADE77xx as there are TIM PWM inputs. The other option is to use an analog multiplexer (CD4051 or similar). The STM32 is quite capable of handling this project.

romario · 2011-12-14 00:07:36

Thank you. How does the SPI comes into play? What could be the approximate cost of the development project?

STPrime · 2011-12-15 19:59:47

I didn't look at the ADE7756. The SPI port makes things a lot simpler. The chip select (CS) allows you to address as many ADE7756 as you want (multiplexed 3 to 8 or an IO expander PCF8591).

The component cost doesn't seem that much. It should be less than $15.00 if you design it yourself. If you want a designed unit, send me your email address.

Thanks,

STPrime

# 1 2011-12-12 11:10:50 Energy meter

Energy meter

# 2 2011-12-13 17:48:25 Energy meter

Re: Energy meter

# 3 2011-12-14 00:07:36 Energy meter

Re: Energy meter

# 4 2011-12-15 19:59:47 Energy meter

Re: Energy meter

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