UNC100 Hardware Manual V1.4 RBH Access Technologies Inc.
Page 33 of 36
Outputs
There are two form C relays and two open collector outputs that can be programmed as general purpose or
default applications. Although the contacts are rated at 12 amperes at 125vac the surge protectors prevent
voltages greater then 40vac or 56vdc from being applied. The recommended use of the relays is to provide
isolated outputs for driving electric strikes or magnetic locks at a maximum voltage of 24v. The open
collector outputs are current limited to 100 milli-amperes direct current only.
Default Output Operation
Lock 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.
Forced / Tamper
The Forced/Tamper output turns on if the door is forced open or if a reader tamper is detected. This output
remains on for as long as the alarm condition exists.
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.
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