12
Combus Specifications
The Combus provides 500 mA at 12 Volts (13.85 VDC). The recommended cable
is #22 AWG. Each loop (module to KT-315) cannot exceed 300 m (1,000 feet) and
the total maximum cable length of all connected loops cannot exceed 1,200 m
(4,000 feet).
For example:
•
Only four wireruns at 1,000 feet from the KT-315.
•
Only eight wireruns at 500 feet from the KT-315.
•
Only ten wireruns at 400 feet from the KT-315
Shielded wire should only be used in areas with excessive RF noise of
electromagnetic interference. Modules can be straight run, connected in a daisy
chain or T-tapped anywhere on the Combus.
Keep in mind that the new modules must be defined in the EntraPass system when they are added to the Combus. Refer to the
Controller Definition
section in the
EntraPass Reference Manual
to learn how to assign modules to your system.
Combus Repower (If required)
Depending on how many modules are connected to the Combus
and how far they are from the KT-315 controller, you may need to
“repower” the controller’s Combus.
The Combus needs to be “repowered” if the voltage drops below
12.5 Volts between black and red wires of the last module of each
loop (the modules will still operate but there will be no
communication between the modules and the controller and a
“Combus module defect” event will be generated from the
controller). This voltage drops if modules are drawing too much
current (500mA maximum for the Combus of each KT-315).
Verify this voltage with a multi meter, and determine if you need to
install a KT-PC4204 in “repower” mode. Using this configuration,
you will be provided with an additional 1 amp of current on the
controller’s Combus. The KT-PC4204 is generally installed at the
beginning of the loop.
When using the KT-PC4204 in “repower” mode, the first relay of the
module will be reserved for the “repower function”. You will have to
assign an “all valid” schedule to the first relay so it is “always
activated” (refer to the Controller definition section of your
EntraPass Reference Manual
for the exact procedure.)
If you are using a KT-PC4204 in “repower” mode and other KT-
PC4204 modules that are assigned as relays 1-4 or KT-PC4216
modules that are assigned as relays 1-16 are also connected to the
same loop, do not use relay 1 of those modules or relay 1 of the KT-
315 door controller. Please also note that all KT-PC4204 modules that are used for Combus repower should be assigned as
relays 1-4.
NOTE:
Jumper 1 “J1” on the KT-PC4204 must be moved to the Combus relay position.
NOTE:
Do not use any power supply other than the KT-PC4204 to repower the Combus. In the event of a power surge or
transient, a module may lock up and cease to communicate with the controller. If the KT-315 loses communication with
the module, it will initiate a module reset and will power down the Combus for five seconds in an attempt to reset the
problem module. After five seconds, the controller will reapply power to the Combus and the problem module should
begin to operate as intended.
