Datasheet

PRELIMINARY
UB20.241
U–Series
24V, 20A, DC-UPS
12. CHECK WIRING AND BATTERY QUALITY TESTS
The DC-UPS is equipped with an automatic “Check Wiring” and “Battery Quality” test.
“Check Wiring” test:
Under normal circumstances, an incorrect or bad connection from the battery to the DC-UPS or a missing (or blown)
battery fuse would not be recognized by the UPS when operating in normal mode. Only when back-up is required
would the unit not be able to buffer. Therefore, a “check wiring” test is included in the DC-UPS. This connection is
tested every 10 seconds by loading the battery and analyzing the response from the battery. If the resistance is too
high, or the battery voltage is not in range, the unit displays “Check Wiring” with the red LED. At the same time the
green “Ready” LED will turn off.
“Battery Quality” or “State of Health” (SoH) test:
Batteries have a limited service life and need to be replaced in a fixed interval which is defined by the specified
service life (acc. to the Eurobat guideline), based on the surrounding temperature and the number of
charging/discharging cycles. If the battery is used longer than the specified service life, the battery capacity will
degrade. Details can be found in chapter
27.1. The battery quality test can not determine a gradual loss in capacity.
However, it can detect a battery failure within the specified service life of the battery. Therefore a battery quality test
is included in the DC-UPS.
A battery problem is indicated with the yellow LED (replace battery pattern) and the green status LED of the affected
battery (switched off). In addition to the indication of the UPS the relay contact “Replace Battery” will be closed.
Please note that it can take up to 170 hours (with the largest size of battery) until a battery problem is reported. This
should avoid nuisance error messages as any urgent battery problems will be reported by the “Check Wiring” test
and create a warning signal.
When “Replace battery” is indicated, it is recommended to replace the affected battery as soon as possible.
13. RELAY CONTACTS AND INHIBIT INPUT
The DC-UPS is equipped with relay contacts and signal inputs for remote monitoring and controlling of the unit.
Relay contacts:
Ready: Contact is closed when both batteries are charged more than 85%, no wiring failure is recognized,
input voltage is sufficient and inhibit signal is not active.
Buffering: Contact is closed when unit is buffering.
Replace Battery: Contact is closed when the unit is powered from the input and the battery quality test (SOH test)
of only one battery reports a negative result.
Relay contact ratings Max 60Vdc 0.3A, 30Vdc 1A, 30Vac 0.5A resistive load
Min 1mA at 5Vdc min.
Isolation voltage Max 500Vac, signal port to power port
Signal input:
7 +
5.1V
3mA
Inhibit
8
-
Inhibit: The inhibit input disables buffering. In normal mode, a static signal is
required. In buffer mode, a pulse with a minimum length of 250ms is
required to stop buffering. The inhibit is not stored. If the voltage on the
inhibit input is lower than 6Vdc the unit continues buffering. See also
section
27.2 for application hints.
Signal voltage Max. 35Vdc
Signal current Max. 6mA, current limited
Inhibit threshold Min. 6Vdc, buffering is disabled above this threshold level
Max. 10Vdc
Isolation Nom. 500Vac, signal port to power port
September 2012 / Rev. 1.3 DS-UB20.241-EN preliminary
All parameters are specified at an input voltage of 24V, 20A output load, 25°C ambient and after a 5 minutes run-in time
unless otherwise noted. It is assumed that the input power source can deliver a sufficient output current.
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