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CENTRIC 3x480, User Guide, rel. 1.7
35
7.2.3
Setup > DC-DC
The Setup >DC-DC menu provides access to parameters related to the dc-to-dc conversion modules.
Most of these parameters are for calibrating the Centric’s readings of the several dc voltages related to the
conversion function.
Remember that the dc-to-dc conversion modules boost the battery voltage to provide the UPS modules the
high voltage they require. The dc-dc modules convert the battery voltage of 540 Vdc to 870 Vdc required by
the UPS modules. The dc-to-dc modules also step down the dc output voltage from the rectifier to a voltage
more suitable for charging the batteries.
Figure 23: "Setup > DC-to-DC" options
7.2.3.1
BATTERY VOLTAGE CALIBRATION
This function is used to correct any inaccuracy in the Centric’s reading of the battery voltage.
(Note: a password may be requested to complete this function.)
The Centric’s readings are calibrated before the UPS leaves the factory, but over time or due to
environmental factors the Centric’s dc measurements may drift slightly.
Keep in mind that in this screen (and in most screens related to dc voltage) the Centric displays the battery
voltage in two parts: a negative half and a positive half. For example, if the battery was charged to the ideal
level of 540 Vdc, and the Centric’s measurement was perfectly calibrated, the battery voltage reading
would be displayed as 270 Vdc negative and 270 Vdc positive.
To detect and correct any inaccuracy in the Centric’s display of the battery voltage:
1.
Measure the actual battery voltage with a calibrated voltmeter. There are labeled battery dc bus bars
inside the UPS. Carefully, observing all safety precautions, measure the voltage between the negative
(“–”) battery bus bar (Figure 24) and the midpoint bus (Figure 22).
2.
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 “battery negative dc voltage” (see Figure 25).
3.
Next, measure the voltage between the positive (“+“) battery bus bar (Figure 24) and the midpoint bus
(Figure 22). If your measured value differs from the Centric’s measured value, enter your measured
value into the field labeled “battery positive dc voltage”.
4.
Press the Confirm button to apply the corrected positive voltage measurements.
