AN939 Datasheet, PDF (9/18 Pages) Microchip Technology – Designing Energy Meters with the PIC16F873A

AN939
FIGURE 6:
ENERGY METER FIRMWARE (GAIN AND FAULT HANDLING ROUTINE)
C
Are
CN and CP
Y
unequal?
N
Set EARTH Flag
to False
Set EARTH Flag
to True
Is sign
of DECISION ^Y
negative?
N
Does
current exceed ^Y
high limit?
N
Is
current below ^Y
low limit?
N
Is
integrated energy
Y
very low?
N
Clear DECISION
and Current
Buffers
Return to ISR
Toggle REVERSE
Flag
Set Amplifier Gain
to Low
Set Amplifier Gain
to High
Clear Buffer
© 2005 Microchip Technology Inc.
DS00939A-page 9