PM9109BF
Similarly by using (4)
Energy for 1 Display increment
= (24000/0.6107)Ws ... (24000/0.0573)Ws
= 39299.2Ws ... 418848.2Ws
= 0.0109kWh ... 0.1164kWh
Any value in this range can be chosen by programming Ks into the device.
How is the calibration factor, Ks, derived?
Ks =
or Ks =
where
(626 * E
Ws
) / (V
LR
* I
LR
)
(626 * 3600 * 1000 * E
kWh
) / (V
LR
* I
LR
)
I
LR
V
LR
E
ws
E
kWh
is
is
is
is
(5)
(6)
rated line current
rated line voltage
energy for one Display increment in Ws
energy for one Display increment in kWh
This formula is valid only if 16µA flows into current sense input for rated line
current I
LR
and 14µA flows into voltage sense input for rated line voltage V
LR
(in
other words - resistor adjustments as shown as example in STEP 1 and STEP 2
must be carried out).
For practical reasons it is standard to use 0.1kWh for 1 Display increment.
Using formula (6) :
Ks =
(626 * 3600 * 1000 * 0.1) / (120 * 200) = 9390
It can be derived that a value of Ks=9390 must be programmed into the device for
0.1kWh for
one Display increment, if I
LR
=200A and V
LR
=120V. This constant
may vary ±10% for calibration purposes.
Using this approach it is shown that:
1) the SA9109B device can be adjusted to any rated values (even orders of
magnitude higher or lower than in this example);
2) ranges for energy per Display increment can be calculated.
This approach also applies to the SA9110A.
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sames
SAMES [ SAMES ]
