UNC500 Hardware Manual V1.3
RBH Access Technologies Inc.
Page
26
of
32
Outputs
The UNC500 has eight outputs, four on side A and four on side B. The Lock and
Forced/Tamper outputs are dry contact relays capable of switching 12Amps@125vac.
The Door Held Open and Alarm Shunt outputs are electronic drivers and can switch
100ma. Outputs are programmable from the PC as normally energized or normally de-
energized. Normally energized outputs are used for fail-safe operation where it is
essential that the output return to a safe state when the system fails due to power loss.
Electronic outputs are ‘switched negative’ which means that they switch the power
negative to the terminal. When the output is off, the output terminal is electronically
disconnected. Outputs can be programmed to operate in a default mode described below
or they can be used as general-purpose outputs. However, the output definition in the
AxiomV
™
configuration software should never be left blank. If the output is unused, use
the default output definitions provided in the AxiomV
™
configuration software.
Switching Inductive Devices (Locks, Bells)
Exercise caution when switching an inductive load. Inductive devices include external
relay, solenoids, bells, and door locks. All of these devices generate extremely high
voltage spikes (
several thousand volts
) when applied power is removed. Possible
disruption of operation could occur if this interference gets on to the electronic circuit
board.
This interference can be suppressed by placing a diode (
1N4001 or similar
) across the
lock or other inductive device being switched. Connect the diode cathode (
end with
band
) to the positive terminal and the other end to the negative terminal. The diode must
be placed at the device being switched and not at the controller.
Default Output Operation
Lock Output (Relay Output)
For magnetic locks, the relay should be configured from the PC as On State de-energized
for fail-safe operation. If power fails (
AC and battery
), the power to the magnetic lock is
removed and the door is opened.
