Ac voltmeter Ampermeter

Hi
I m doing ac 220 volt 50 hz voltmeter and ampermeter with f877. What is the best way for do this.

I m using f877 adc.
Thanks.

For current:

• http://www.allegromicro.com/hall/currentsensor.asp

For voltage, use a unregulated DC wall transformer to drop the voltage to a safe level and a voltage divider to get it in ADC range.

Thanks for answer.
Another question:
I must do fast electronic fuse using this amp. and voltmeter.
For ex: When current over my set limit, pic output pin must be shutdown very quickly,must be more speed from main ac fuse.
Anybody done do this before?I need some tips or schematic or code ex.

Thanks.

i would use a comparator interrupt. If the comparator input is greater than the reference, it jump to an Interrupt routine, in there you Shut down the external devices.

could be done with the ADCs reading too... it's just slower.

Hi

Im new to this forum and have been looking into designing a project that uses a hall effect sensor to measure AC current, (50hz 240v mains AC)
the sensor i have got is CSLA2CD

and has the following datasheet:
http://pdf1.alldatasheet.com/datashe...C/CSLA2CD.html

the sensor can measure upto 72Amps, and has a linear output that will basically track the input waveform eg. AC voltage output
the device outputs half the supply voltage at 0amps, and the output range is 25-75% of the supply voltage.

The range of current i wish to measure is 0 - 50amps

I think the easier solution is to convert the AC voltage to a DC level

Does anyone have a circuit diagram that can inferface the sensor with the A/D input of a PIC eg PIC16F872?

Thanks
Dave