Table 5 - Door Lock Relay Assignments & Ribbon Cable Connections - Keyscan CA250 Series Technical Manual

 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.
Door Strike Diodes
Keyscan access control units include diodes. Install diodes across all DC door strikes as shown in Figure 24 on
page 39. The cathode of the diode connects to the positive side of the strike at the door. The anode of the
diode connects to the common return wire.
Diodes must be installed for proper operation.
Fail Safe/Fail Secure Lock Devices
The power supply's positive output connects to the common on the door relay output.
For 'fail-safe' and 'fail-secure' door strikes, observe the following relay connections:
 'Fail-safe' – connect the positive terminal on the door strike to the 'normally closed' position on the relay
board. Connect the return wire to the common on the DC power supply via the metal enclosure's ground
lug
 'Fail-secure' – connect the positive terminal on the door strike to the 'normally open' position on the relay
board. Connect the return wire to the common on the DC power supply via the metal enclosure's ground
lug
Warning
Before securing any exit, please ensure all wiring to electrical door hardware conforms to federal, state,
provincial, or municipal fire regulations and building codes.
Table 5 – Door Lock Relay Assignments & Ribbon Cable Connections
Control Board/OCB-8
CA250B/OCB-8
CA4500B/OCB-8
Keyscan Inc. – Technical Guide (PC109x - 07.15)
Door # /Relay #
Door 1/Relay 1 (K1)
Door 2/Relay 2 (K2)
Door 1/Relay 1 (K1)
Door 2/Relay 2 (K2)
Door 3/Relay 3 (K3)
Door 4/Relay 4 (K4)
Ribbon Cable Connection OCB-8 to
Control Board
Connect ribbon from H1 on OCB-8 to Control 1 on
CA250B
Connect ribbon from H1 on OCB-8 to Control 1 on
CA4500B.
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