DSC SYSTEM MASTER PC4000, System Manual, Page: 5 / 32

3
GETTING
STARTED
When designing a security system with the PC4000
that will be larger than 16 zones or have two or more
Partitions it is best to first lay out the system on paper.
This will help determine the total number of zones,
additional expansion and power supply modules and
other system elements that may be needed.
When the location of all points of protection is known
the location of the zone expanders can be made. You
will find that working from a plan, a layout will reveal
the most economical use of system modules; two eight
zone expansion modules instead of one sixteen zone,
for example, can save long wire runs because of the
location of zones.
The plan will also enable you to make the most efficient
layout for the communications bus (COMBUS). This is
the four conductor cable which can be standard station
wire (four 22 AWG wires color coded red, black , yellow
and green) to which all system modules are connected
in parallel. It is not necessary to run the COMBUS in
shield unless it is being run through an area of high
electrical noise.
The COMBUS may be up to 1,000 ft (300 m) from the
main board to the farthest module, with any number of
modules in between. More than one COMBUS of 1,000
ft (300 m) can run from the PC4000.
When zone expanders are enrolled to the PC4000 the
zones will be added to the system in sequence. For
example, if an eight zone expander (PC4108) is added
the additional zones would be assigned the next eight
zones available on the system. As the first sixteen zones
are on the main panel the additional zones, 17 through 24
would be assigned to the eight zone expander. If a
sixteen zone expander (PC4116) were to follow the eight
zone expander it would receive zones numbered from 25
to 40.
On your layout, determine the order in which the zone
expanders will be enrolled to the system. This will allow
you to correctly assign zone numbers.
Next determine the number of keypads required for
each Partition and their location on the system. The
maximum number of keypads allowed is 16.
When the number of zones, keypads and their locations,
expansion modules and separately controlled systems
(Partitions) have been decided upon you can now
determine what other modules in the PC4000 system
you require to complete the installation.
The PC4400 provides serial output to an on-site printer
that will record the identity of the system, description of
the occurrence (alarm, trouble etc.) arm/disarm by user,
date and time. The PC4216 module provides up to 16 programmable
outputs each of which may be programmed to trigger
on up to 21 different options. It is also used to display
zones on a graphic annunciator. When used in this
manner all 16 outputs must be used to display alarm
inputs. A total of eight PC4216 modules would be
needed to display all 128 zones of the PC4000.
COMBUS Power and Operation
The PC4000 main board can provide up to 500 mA to
power modules, keypads and devices. A PC4204 power
module is required when additional current is needed
either for powering detection devices or operating bells
and sirens. The PC4204 requires its own transformer and
battery and can provide up to 1.5A at 12 VDC. Four
relays on the module provide form C switched outputs
with contact ratings of 3 amps @ 12 VDC for a variety of
programmable options. When used to repower the
COMBUS the PC4204 must be wired in accordance with
the instructions supplied with the unit. Use of a power
source other than the PC4204 power supply module to
supply additional power to the PC4000 system is not
recommended for the following reasons:
If the main panel loses communications with a module,
within a maximum of 90 seconds the panel will perform
a system reset in which power to the COMBUS is
removed. Five seconds later power is reapplied and
the panel will attempt to communicate with the module.
If the panel is unsuccessful communicating with the
module it will display and report a COMBUS
communications fault.
When the main panel performs a reset, relay 1 when
programmed for “COMBUS POWER” will open. This will
disconnect the power supplied to the modules, resetting
them so that communications to the main panel are
reinitialized.
For example, if the microprocessor on the module has
been scrambled due to a transient, the PC4000 will
power down the COMBUS, the PC4204 will mimic the
PC4000 and cut off its power supply to the module.
The module will be powered down. When the PC4000
returns power to the COMBUS, the PC4204 will
reconnect its power supply, and the power to the
module will return. Because the module was powered
down and powered up, the module is now reset, and
can communicate with the PC4000.
If a power supply other than a PC4204 was used, the
module would never power down, never reset, and the
module will stay off line requiring the attention of service
personnel.