PS20 Operating Manual RevD.doc
2016-10-20
1
Power Supply
Type PS20
v3.2 Rev. D
P
RODUCT
D
ESCRIPTION
The PS20 is dedicated for electronic equipment which require 12VDC buffered supply
source. Device consist of metal case with compartment for sealed lead-acid battery,
mains transformer and electronic circuit. PS20 may deliver up to 2A current without any
time limit, it utilize DC/DC “switched mode” electronic circuit which offer high efficiency
(reduced heating of electronic components). PS20 employs internal current limiting and
short circuit protection which make it essentially indestructible. The reserve battery is
connected to output terminals trough an ultra low-resistance MOS transistor, such a
circuit architecture enables optimum performance during AC failure and during dynamic
changes of load when excessive current consumption is required. PS20 charge battery
with
constant current-constant voltage
method, this method of charging guaranties
relatively quick and safe charging process. The initial charging current is factory set to
~300mA, installer should be aware that with battery connected to PS the output current
will be reduced to 1700mA. Depending on battery charging phase the output voltage of
PS20 may vary from approx. 11.5 up to 13.8V level. When battery voltage drops below
~10.0V level internal circuit disconnect it from load, battery is automatically reconnected
when AC supply returns. Battery cut off circuit protect battery from deep discharge but
the equipment connected to power supply from operation below 10.0V level which in
many cases can lead to undefined system behavior. Battery is protected with 5A fuse
which reduce maximum output current sourced from battery and electronic circuit
against battery reverse connection. PS20 offer two output ports (Z1 and Z2 terminals).
The nominal output voltage is factory set to 13.8V and should not be changed by user.
PS20 is equipped with two LEDs, the red one (marked as 230VAC) signalize that AC
power exists where the second one (marked as 12VDC) signalize that output voltage is
available.
O
PTIONAL
A
LARM
M
ODULE
PSAM-1
For more sophisticated installation electronic circuit of PS20 can be equipped with
optional alarm module (PSAM-1). This module can be connected to PS20 circuit through
dedicated connector (CON4) which is located on PS20 board. The main purpose of PSAM-
1 module is to signalize an alarm situation of power supply to external device or system.
The PSAM-1 may operate in autonomic or networked mode. When set to autonomic
mode it offer three transistors outputs which are dedicated to signalize following
situations:
-
low battery
-
battery failure
-
AC lost
Those outputs can be connected to external control panel, access controller or another
control or signaling device which will warn authorized personnel.
When PSAM-1 operates in networked mode it must be connected to PR series access
controller (PR302/PR402 or PR302LCD) through Clock & Data interface. In this mode
PSAM-1 module sends all messages about power supply condition direct to access
controller. During
networked
mode PSAM-1 signalize the same alarm condition as during
standalone mode and additionally delivers data about actual voltage level available on
PS’s output terminals.
