Datasheet

Data Sheet ADE7953
Rev. B | Page 41 of 72
Active Energy No-Load Status Bits
In addition to the active energy no-load interrupt, the ADE7953
includes two unlatched status bits that continually monitor the
no-load status of Current Channel A and Current Channel B.
The ACTNLOAD_A and ACTNLOAD_B bits are located in the
ACCMODE register (Address 0x201 and Address 0x301). These
bits differ from the interrupt status bits in that they are unlatched
and can, therefore, be used to drive an LED.
REACTIVE ENERGY NO-LOAD DETECTION
Reactive energy no-load detection can be used in conjunction
with active energy no-load detection to establish a “true” no-load
feature. If both the reactive and active energy fall below the no-load
threshold, there is no resistive, inductive, or capacitive load. The
reactive energy no-load feature can also be used to prevent creep
of the reactive energy when there is a resistive load present.
If the reactive energy on either Current Channel A (phase) or
Current Channel B (neutral) falls below the programmed thresh-
old, the reactive energy on that channel ceases to accumulate in
the RENERGYA and RENERGYB registers, respectively. If either
the CF1 or CF2 pin is programmed to output reactive energy, the
CF output is disabled and held high (see the Energy-to-Frequency
Conversion section). If enabled, the reactive reverse power indi-
cation holds its current state while in the no-load condition (see
the Reverse Power section). The Current Channel A reactive
energy no-load condition is indicated by the VAR_NOLOADA
bit (Bit 7) in the IRQSTATA register (Address 0x22D and
Address 0x32D). The Current Channel B reactive energy no-
load condition is indicated by the VAR_NOLOADB bit (Bit 7)
in the IRQSTATB register (Address 0x230 and Address 0x330).
Current Channel A and Current Channel B are independent
and, therefore, a no-load condition on Current Channel A
affects only the energy accumulation, CF output, and reverse
power of Current Channel A, and vice versa.
The reactive energy no-load feature is enabled by default and
can be disabled by setting Bit 1 in the DISNOLOAD register
(Address 0x001) to 1.
Reactive Energy No-Load Interrupt
Two interrupts are associated with the reactive energy no-load
feature: one for Current Channel A (phase) and one for Current
Channel B (neutral). If enabled, these interrupts are triggered
when the reactive energy falls below the programmed threshold.
The Current Channel A reactive energy no-load interrupt can be
enabled by setting the VAR_NOLOADA bit (Bit 7) in the IRQENA
register (Address 0x22C and Address 0x32C). When this bit is set,
a reactive energy no-load event on Current Channel A causes
the
IRQ
pin (Pin 22) to fall to 0 (see the Primary Interrupts
(Voltage Channel and Current Channel A) section).
The Current Channel B reactive energy no-load interrupt can be
enabled by setting the VAR_NOLOADB bit (Bit 7) in the IRQENB
register (Address 0x22F and Address 0x32F). When this bit is set, a
reactive power no-load event on Current Channel B triggers the
IRQ
alternative output (see the Current Channel B Interrupts
section).
Reactive Energy No-Load Status Bits
In addition to the reactive energy no-load interrupt, the
ADE7953 includes two unlatched status bits that continually
monitor the no-load status of Current Channel A and Current
Channel B. The VARNLOAD_A and VARNLOAD_B bits are
located in the ACCMODE register (Address 0x201 and Address
0x301). These bits differ from the interrupt status bits in that
they are unlatched and can, therefore, be used to drive an LED.
APPARENT ENERGY NO-LOAD DETECTION
Apparent energy no-load detection can be used to determine
whether the total consumed energy is below the no-load thresh-
old. If the apparent energy on either Current Channel A (phase)
or Current Channel B (neutral) falls below the programmed
threshold, the apparent energy on that channel ceases to
accumulate in the APENERGYA and APENERGYB registers,
respectively. If either the CF1 or CF2 pin is programmed to
output apparent energy, the CF output is disabled and held high
(see the Energy-to-Frequency Conversion section). The Current
Channel A apparent energy no-load condition is indicated by the
VA_NOLOADA bit (Bit 8) in the IRQSTATA register (Address
0x22D and Address 0x32D). The Current Channel B apparent
energy no-load condition is indicated by the VA_NOLOADB
bit (Bit 8) in the IRQSTATB register (Address 0x230 and
Address 0x330).
Current Channel A and Current Channel B are independent
and, therefore, a no-load condition on Current Channel A
affects only the energy accumulation and CF output of Current
Channel A, and vice versa.
The apparent energy no-load feature is enabled by default and
can be disabled by setting Bit 2 in the DISNOLOAD register
(Address 0x001) to 1.