Schlage PIB300 User Manual page 325

Earth Ground
and Shielding
NOTE
two pins protruding up from the main logic board are not connected to each other.
This effectively opens the circuit, removing the battery from any internal circuitry. Main
input power can then be removed and the HandReader will fully shut down. Once the
HandReader has fully shut down, shunt J7 may be reinstalled. The design of the power
supply is such that main input power must be reapplied to re-enable the battery protection
mechanism. If shunt J7 is not properly installed, the internal backup battery will not be
charged, and in the event of a main input power loss, the HandReader will shut down.
The HandReader with the battery backup option uses a 12 volt 800 ma/hour sealed lead
acid battery to provide backup battery power. This battery is located immediately inside
the rear panel of the HandReader and plugs into jack J4 on the keypad control circuit
board located in the top of the chassis.
Schlage Biometrics recommends that all HandReaders be grounded with a solid, reliable
earth ground connection. This connection establishes a common ground return point
used to protect internal semiconductor devices from ElectroStatic Discharge (ESD) and
from external signal line transients. It also provides a common signal level reference point
between externally networked HandPunchs. Schlage Biometrics recommends that the
earth ground source be identified by a qualified electrician familiar with electrical codes
as well as wiring and grounding techniques.
This is an extremely important and often overlooked aspect of hard-wired serial
communication systems. If the sending and receiving stations do not agree on the ground
reference for the signal voltages, communication errors or a total inability to communicate
may be observed. If the voltages are very different, it is even possible to damage the
units.
The subject of grounding can be complicated, and the full circuit of a system, including
power supplies and often even the building line power wiring, must be understood. It
is strongly recommended that a qualified electrician or electrical engineer familiar with
this subject be consulted when designing the wiring of an HGU network installation.
Always adhere to any applicable electrical codes for your area. Schlage Biometrics is not
responsible for damage done to units due to improper wiring.
Use any one of the following ground terminals to make the earth ground connection: 4,
10, or 13. Do NOT use terminal 2 to establish the earth ground connection; terminal 2 is
not directly connected to ground.
HandKey II Manual
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