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CENTRIC 3x480, User Guide, rel. 1.7
7.2.3.3
CHARGER CURRENT CALIBRATION
Use this function if it necessary to recalibrate the ampere readings of one of the UPS's input phases.
In order to calibrate the charging current, you have to ensure that there is charging current. This can be
done by manually invoking a battery test (“Main > Operation > Battery Test > Test Battery”) shortly before
you perform the calibration, to lower the battery voltage below its normal level.
For your reference, the present UPS-measured values are displayed on the right side of the screen.
Calibration of the charger current should be performed when the system is under a very light load or no
load.
(Note: a password may be required to perform this function.)
To calibrate the Centric’s display of the charger current:
1.
With the UPS in normal mode, turn of the ac input (Main > Operation > Turn ON/OFF > Modules Off >
Select All > Inverter Off).
2.
Turn off all dc-dc blocks except for one (“Main > Operation > Turn on/off > Dc-dc ON/OFF”).
We suggest you calibrate the dc-dc blocks starting with the bottom-most block (see Figure 26).
3.
The battery bus is located inside the lower part of the UPS (Figure 24). Using a calibrated ammeter,
measure the actual dc current between the negative (“–“) battery bus and the midpoint bus (Figure
22).
4.
Compare your measured value to the number to the right of the screen, which is the Centric’s
measurement. If your measured value differs from the Centric’s measured value, enter your
measured value into the field labeled “Charger negative” (see Figure 25).
5.
Next, measure the voltage between the positive (“+“) dc bus and the midpoint bus bar. If your
measured value differs from the Centric’s measured value, enter your measured value into the field
labeled “Charger positive”.
6.
Press the Confirm button to apply the corrected measurements.
7.
Switch off the dc block you just calibrated and switch on the next-highest block (see the sequence
numbers in Figure 28.
8.
Repeat steps 3 through 7 until all of the dc-dc blocks have been calibrated.
Figure 28: Charger current calibration screen
