zigbee (AC voltagemonitoring)+PIC ADC

[karthi_keyan]

hai all ,

i am using zigbee module(maxstream) and the module sends ADC values (0-1023)according to the AC voltage and its successfully received by my PIC24F controller.finally i have a problem when converting adc values into AC voltage .can any one help me to fix the problem.
also referred some sites in that they said the following conversions,
1.they keep max_v,min_v(voltage values)
2. avgv = (max_v + min_v) / 2 .(taking average voltage)
3.vpp = max_v-min_v(peak to peak measurement)
4.voltagedata - = avgv(removing DC bias from voltage level)
5.finally they keep some MAINVPP value with voltage level conversion they said the value for mains voltage is 120Vrms = +-170Vpp.
voltagedata = (voltagedata * MAINSVPP) / vpp(i struggled with MAINSVPP value)
pls any one explain this or some other ways to convert.


> thanks & regards,
> karthikeyan

 

[engr_najam]

what are ur maximum and minimum applied voltages ?

any how there is a simple way, suppose these five are your values.

a =

0 256 512 768 1024

converted vales are as

b=a*5/1024

b =

0 1.2500 2.5000 3.7500 5.0000


where 5 will be ur maximum voltage and 0 as ur minimum voltage, and 1024 is maximum possible value of ur ADC sample