Power Requirements
Specific power requirements must be met for the entry station to function correctly. If these are not met there is a
risk of damaging the unit or encountering performance issues.
Power requirements are listed in the Technical Specifications (see page51).
The entry station requires a minimum supply of 10V to operate correctly. Voltage drop between the power supply
and the entry station may cause the entry station to receive insufficient voltage. If this occurs the display may be
faint or flickering and the unit may reboot unexpectedly.
When designing the supply of power to the entry station, ensure that you account for the following factors which
may contribute to voltage drop:
⦁The run length (length of cable from power supply to entry station)
⦁The composition of the wire
⦁The CSA(cross-sectional area) / AWG of the cable
⦁The temperature of the cable and how mechanical protection applied to the cable relates to the temperature
After installation, we recommend that you measure the input voltage at the entry station to ensure that it is
sufficient for correct operation.
Cable Length and Gauge
The length and gauge of the cable connecting the entry station to the power supply will affect the voltage being
supplied to the entry station. By identifying the allowable voltage drop (the power supply voltage minus the 10V
minimum operating requirement) and dividing this by the voltage drop per meter (the wire resistance multiplied
by the entry station's maximum operating current) you can calculate the maximum cable length that can be used.
The following formula can be used as a guide to calculate the maximum cable length.
⦁Cable length = 0.5 * (VPSU - 10.0/0.132)/(RWire * 4.0)
where RWire = wire resistance per meter
Using the 20AWG example in the table below, this would be calculated as 0.5 * (13.8 - 10.0)/(0.033 * 4.0) = 14.4m
Note: This assumes that no other devices are drawing current from the power supply. Any additional devices will
reduce the power supply's capacity and affect the maximum cable length.
PRT-ENTR-17 | Protege Vandal Resistant Touchscreen Entry Station | Installation Manual 10