Microchip Technology ARD00330 データシート
Energy Monitoring PICtail™ Plus Daughter Board User’s Guide
DS51933A-page 24
© 2011 Microchip Technology Inc.
3.15
RAW_POWER_ACT
This register is the raw active power, as it represents the sum of current A/D value times
voltage A/D value results over LINE_CYC line cycles (each line cycle has 128 results).
Each current times voltage multiplication results in a 32-bit word. There are up to 256
line cycles with each line cycle being 128 results, and each result being 32-bit. Thus,
48 bits are needed. This is the register to be read during calibration for calculating the
offset and gain values associated with active power, OFFSET_POWER_ACT and
GAIN_POWER_ACT. This register is overwritten every line cycle, however if the cali-
bration is enabled, the updates will stop once the LINE_CYC line cycles have elapsed.
voltage A/D value results over LINE_CYC line cycles (each line cycle has 128 results).
Each current times voltage multiplication results in a 32-bit word. There are up to 256
line cycles with each line cycle being 128 results, and each result being 32-bit. Thus,
48 bits are needed. This is the register to be read during calibration for calculating the
offset and gain values associated with active power, OFFSET_POWER_ACT and
GAIN_POWER_ACT. This register is overwritten every line cycle, however if the cali-
bration is enabled, the updates will stop once the LINE_CYC line cycles have elapsed.
3.16
POWER_ACT
This register is the value for active power. The goal of the calibration is to get this reg-
ister value to equal X W/LSB. This is done with the OFFSET_POWER_ACT and
GAIN_POWER_ACT registers. When displaying the power, multiply the (decimal)
value in this register by X to get the display value in Watts. This register is overwritten
every LINE_CYC line cycle (written only once if the calibration is enabled).
ister value to equal X W/LSB. This is done with the OFFSET_POWER_ACT and
GAIN_POWER_ACT registers. When displaying the power, multiply the (decimal)
value in this register by X to get the display value in Watts. This register is overwritten
every LINE_CYC line cycle (written only once if the calibration is enabled).
3.17
POWER_APP
This is the value of the apparent power. The goal of the calibration is to get this value
to equal X VA/LSB. This is done with the GAIN_POWER_APP registers. When display-
ing the power for phase A, multiply the (decimal) value in this register by X to get the
display value in Watts. This register is overwritten every LINE_CYC line cycle (written
only once if the calibration is enabled).
to equal X VA/LSB. This is done with the GAIN_POWER_APP registers. When display-
ing the power for phase A, multiply the (decimal) value in this register by X to get the
display value in Watts. This register is overwritten every LINE_CYC line cycle (written
only once if the calibration is enabled).
3.18
RAW_POWER_REACT
This is the raw reactive power. This register is read during the calibration for calculating
the gain values associated with the reactive power and GAIN_POWER_REACT. This
register is overwritten every LINE_CYC line cycle (written only once if the calibration is
enabled). This register is accumulated once a line-cycle basis.
the gain values associated with the reactive power and GAIN_POWER_REACT. This
register is overwritten every LINE_CYC line cycle (written only once if the calibration is
enabled). This register is accumulated once a line-cycle basis.
Name
Bits
Cof
RAW_POWER_ACT
64
R
Name
Bits
Cof
POWER_ACT
32
R
Name
Bits
Cof
POWER_APP
32
R
Name
Bits
Cof
RAW_POWER_REACT
64
R