Keri Systems NXT 4-D - Manual (Page 3)

NXT 2-D/4-D Controller
Installation Guide
Page 3 of 6 P/N: 01997-001 Rev. I
1.3 Port Protection
Transorbs are provided with the controller ship kit. They are used to protect the controller from voltage spikes induced on
the port wiring by absorbing the excess voltage and slowly releasing it back into the circuit. Keri strongly recommends
wiring in the transorbs provided with the controller ship kit. Refer to the Transorb Wiring Diagram below.
NOTE: The Transorbs that Keri provides are non-polar; they can be installed in either orientation.
1.4 Isolation Relays
For locking devices that may induce heavy voltage spikes – Mag Locks and devices with heavy-duty solenoids such as
turnstiles, vehicle gates, and overhead doors – Keri recommends using isolation relays. Keri has an Isolation Relay Kit

(p/n IRP-1). Please refer to the IRP-1 Isolation Relay Installation Guide (p/n 01833-001) for detailed information.
1
2
3
4
5
6
NO - Relay
Common - Lock / Alarm - Relay
NC - Relay
Door Switch - Input
Ground
REX - Input
–
+
Power
Supply
Fail-Secure
Electric Lock Device
or
Alarm
–
+
1
2
3
4
5
6
NO - Relay
Common - Lock - Relay
NC - Relay
Door Switch - Input
Ground
REX - Input
–
+ Power
Supply
Fail-Safe
Electric Lock
Device
–
+
Port
Terminal Block
Port
Terminal Block