SA9604A
6. Register Values
The 24 bit registers are up/down counters, which increment or decrement at a rate
of640k/s(640k*2/PIforreactive)atratedconditions. Theenergyregistervalueswill
increment for positive energy flow and decrement for negative energy flow as can
be seen in the following diagram:
register wrap around
positive energy flow
Register values
H7FFFFF H800000
(8388607) (8388608)
HFFFFFF
...............
...............
0
(16777215)
negative energy flow
register wrap around
At power-up the register values are underfined and for this reason the msb of the
delta value (delta value = present register value - previous register value) should
be regarded as an indication of the measured energy direction. (0 = positive, 1 =
negative).
The delta value for the energy registers is between 0 and 8388607 for positive
energy flow and between 0 and -8388607 for negative energy flow. For voltage the
maximum usable delta value is 16777215 as voltage is in a positive direction only.
When reading the registers care should be taken to check for a wrap around
condition.
As an example lets assume that with a constant load connected the delta value is
22260. Because of the constant load, the delta value should always be 22260 every
time the register is read and the previous value subtracted (assuming the same time
12/20
sa m e s
SAMES [ SAMES ]
