GE Security EST3 Installation And Service Manual page 105

Access control applications
Power supply
The figure shows an independent power source for the CRC.
This is suggested due to the length of cable from the cab to the
electrical room.
Two pairs of wires are used to connect the CRC to the control
panel. The SAC bus requires one pair for data communication.
One wire of the second pair is required to maintain a common
ground between the control panel and the CRC. For details, refer
to the topic "Power from an AC source," later in this chapter.
If you use an additional power supply other than the CRCXF,
that power supply must be listed for fire alarm applications, must
have ground fault detection disabled, and must have a circuit
ground (circuit common) that is isolated from earth ground.
Hardware configuration
In this application, none of the CRC input circuits or relay
contacts are used. The CRC simply reads the card and passes the
command list request to the 3-SAC and CPU for processing.
Since the CRC lock and input circuits are not used, you must
provide dummy loads to maintain correct supervision currents.
See the installation sheet for the correct load values.
SDU programming
The SDU programmer must create a command list for each
combination of floors desired.
ACDB operation
The site security officer determines which floors should be
accessible for an access level, and assigns the correct command
list to the access granted event for that level. The site security
officer also determines which cardholders belong to each access
level.
EST3 Installation and Service Manual 3.23