Terminating Cables At Door Control Units; Outputs; Terminate Lock Wiring At The Ocb-8 - Keyscan CA250 Series Technical Manual

Terminating Cables at Door
Control Units
The following sub-sections review termination of input and output cables at the access control unit for locks,
input devices, readers, and auxiliary output devices.
This section reviews outputs and associated diagrams followed by inputs and associated diagrams.

Outputs

Outputs, such as door locks or auxiliary devices, connect to Keyscan's OCB-8 relay board that in turn, via a
ribbon cable, connects to a specific header on the control board depending on the type of output. Keyscan door
control units support the following types of outputs:
 Door lock output
 Auxiliary output
 Extended entry output (for mechanical door operator)
 Pre-alert output
 Global output
The following sub-sections review cable connections and ribbon cable assignments for each type of output

Terminate Lock Wiring at the OCB-8

Depending on the series of door control unit, the following table outlines door relay assignments for the
CA250B, CA4500B and CA8500B and the ribbon cable connection.
Normal and Reversed OCB-8 Relays
OCB-8 relay boards have DIP switches that may be set to "normal" or "reversed". Each relay has an LED that
indicates the relay status:
 Normal – LED on the circuit board is not illuminated when door is locked
 Reversed – LED on the circuit board is illuminated when door is locked
Relay output and DIP switch assignments are on the OCB-8 diagrams on the succeeding pages.
Door Lock Power Supplies
Use a separate power supply for door strikes and other 12 VDC equipment. The power supply should have
battery backup for continued operation during a power failure. When adding equipment to an existing system,
be sure the power supply can withstand the increased current consumption.
Determine Power Supply Current Requirements
Use a power supply that has sufficient current capacity for all connected devices. Factor in a reserve allowance
for peak current demands when determining the power supply. Use the following formula that includes a 30%
tolerance factor when calculating total current requirements for power supplies:
Keyscan Inc. – Technical Guide (PC109x - 07.15) 34