PR411DR Installation Guide Rev.K.doc
2016-10-28
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Fig. 5 LEDs at PR411DR-BRD controller PCB
3.3 Power supply
Basically, PR411DR and PR411DR-BRD controllers are designed for power supply from
230VAC/18VAC transformer with minimal power output 25VA, but they can also be supplied with
12VDC or 24VDC. The connection of power supply is shown in fig. 6, fig.7 and fig. 8.
If controller is supplied with 18VAC or 24VDC, then 12V backup battery can be connected in order
to provide power supply in case of mains supply shortage. The controller charges backup battery
with 300mA stabilized current up to 13.8V. Backup power supply is activated automatically in case
of main powers supply shortage. If the voltage at backup battery drops below approx. 10V then the
battery is automatically disconnected from controller and remains disconnected until mains power
supply returns. Depending on charging phase of backup battery, the voltage at AUX and TML
terminals may vary in range of 11V (initial charging phase) to 13.8V (final charging phase) which is
not a symptom of failure but it results from applied concept of battery charging.
In case of 12VDC power supply, backup battery cannot be directly connected to controller and in
such case backup power supply must be provided by 12VDC power supply unit.
General guidelines for 18VAC power supply
GND terminals of controllers must be connected with any wire.
Controllers can operate with directly connected backup batteries.
Controllers cannot be started using only power supply from backup battery.
