Schlage PIB300 User Manual page 218

Planning An Installation
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
NOTE
connection: 4, 10, or 13. Do NOT use terminal 2 to establish the earth ground
connection; terminal 2 is not directly connected to ground.
Figure 2-2: Earth Ground Connection Terminals
14
CARD
OUTPUTS
READER
INPUT
1 2 3 4 5 6 7 8 9 10 11 12 13 14
EARTH GROUND ONNECTI ON PIN
SWITCH
INPUTS
C