DCW20
User Manual rev. 5
Page 14/34
3.3 Current limit
DCW20
has the ability to limit the current flowing through its input, output and battery terminals to a
user settable threshold.
3.3.1 Current limit in UPS mode
In UPS mode DCW20
provides 3 different settings for the current limit:
Maximum input current
(§4.2.21), default 20A: it is used to limit the input current at a
specified threshold. For example if the DC power supply is rated less than 20A the threshold
can be lowered to avoid too high current drain from the power supply. When the input current
limit is reached the battery charging current is limited; if the input current can not be kept below
the threshold due to excessive loading an input overcurrent alarm is triggered. When the input
current is approaching the threshold, the measured input current is displayed with red fonts on
the LCD.
Maximum output current
(§4.2.22), default 20A: it is used to limit the maximum current
delivered to the load. When the threshold is reached due to excessive loading an output
overcurrent alarm is triggered. When the output current is approaching the threshold, the
measured output current is displayed with red fonts on the LCD.
Battery maximum discharge current
(§4.2.11), default 20A: it is used to limit the maximum
discharge current delivered from the battery during the backup function. When the threshold is
reached due to excessive loading a battery overcurrent alarm is triggered and the output
voltage starts to decrease. When the battery discharge current is approaching the threshold,
the measured battery current is displayed with red fonts on the LCD.
3.3.2 Current limit in DC/DC mode
In DC/DC mode DCW20
provides 2 different settings for the current limit:
Maximum input current
(§4.2.21), default 20A: it is used to limit the input current at a
specified threshold. For example if the DC power supply is rated less than 20A the threshold
can be lowered to avoid too high current drain from the power supply. When the input current
limit is reached due to excessive loading an input overcurrent alarm is triggered. When the
input current is approaching the threshold, the measured input current is displayed with red
fonts on the LCD.
Maximum output current
(§4.2.22), default 20A: it is used to limit the maximum current
delivered to the load. When the threshold is reached due to excessive loading an output
overcurrent alarm is triggered and the output voltage starts to decrease. When the output
current is approaching the threshold, the measured output current is displayed with red fonts on
the LCD.
3.4 Inhibit
An
opto-isolated input
allows the inhibition of the backup function in UPS mode or switching off the
output on DC/DC mode. The
polarity of the input can be defined using the “
Inhibit polarity
” field
(§4.2.28).
DCW20_040-02-700-005-EH-1117