User's Manual

POWER DISTRIBUTION & READER HOOKUP

12 Power Distribution & Reader Hookup

Each of the PIV-Station readers offers RS-232, RS-485, and USB communication channels for communicating

with a PC or host controller. Each reader also uses the Wiegand protocol to interface with Access Control

equipment, such as access controllers (outputs) or additional readers (inputs). The PIV-Station product will rely

on power provided to the system for operation. In a small installation, power may be provided by means of an

AC adapter placed near the PIV-Station reader itself. In larger installations, power will be distributed from either

a central source or various sources.

12.1 V-Station Power

Power to the PIV-Station readers should be:

• Isolated from other equipment.

• Filtered.

• Protected by means of an uninterruptible power supply (UPS) or battery backup.

• If transient electrical surges are an issue in the location, a voltage suppression device is also

recommended.

When planning a system, know the power requirement of each reader. If multiple readers are to share a

common power supply, care must be exercised to avoid excessive voltage loss on the wires. Voltage loss can

lead to communication problems when readers are talking and/or listening on different ground references.

Voltage loss is directly proportional to wire resistance and the current the wire carries. Place the power supply

as close to the equipment as possible. Select appropriate wire size for the load. The PIV-Station readers run

on DC power between 12.5 and 24 VDC. Power requirements are as listed in Table 4.

V-Station (all models)

Power Requirement:

12 watts

Input Voltage Range:

12.5-24.0 VDC

Peak Current:

12 VDC 1 A

24 VDC 500 mA

Table 4: PIV-Station Power Requirements

12.2 Selecting the Right Power Supply

Most power supplies in the market today provide good input/output isolation, however those which do not

provide isolation (or have high leakage capacitance), coupled with accidental AC power line interchange,

present serious ground fault problems for installers. With ground fault, the signal reference between

subsystems may be 115 VAC apart. If these subsystems are interconnected, the large potential difference will

cause equipment damage or personal injury. We recommend only the use of a 12.5 VDC, 1 A, isolated, UL-

Listed Class II power supply.

All factory supplied power supply assemblies are either switching or regulated linear supplies and are isolated

for safety and to minimize ground loop problems.