Keyscan Inc. – Technical Guide (PC109x - 04.15)
Terminate Wiring at the
ACU
The following sub-sections review terminating lock, input, elevator, reader, and auxiliary output wiring at the
access control units.
OCB-8 Relay Board
Keyscan’s OCB-8 relay board is used for terminating door locks, magnetic locks, elevator relays, and
alarm/auxiliary outputs at the access control unit.
Table 3 – OCB-8 Specifications
Form C contacts, 30 VDC 5 Amps, 24 VAC 10 Amps
8.6 cm x 12.5 cm (3 3/8” x 4 7/8”)
Temperature: 5° C to 49° C (41° F to 120° F)
Humidity: 0% to 90% R.H., non-condensing
Terminate Lock Wiring
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.
To calculate total current requirements for power supplies, use the following formula that includes a 30%
tolerance factor:
Total Current = (Device A amps + Device B amps + Device C amps, etc.) x 1.30
Example
An installation calls for one magnetic lock and three door strikes requiring 12 VDC:
Mag Lock – 100 mA + Door Strike A – 200 mA + Door Strike B – 200 mA + Door Strike C – 200 mA x
1.30 = 910 mA
In this example, a separate 1-amp power supply is sufficient.
Important
The total combined current of the devices must not be greater than the current rating of the power
supply.