Supervised Wiring for Access Control

Learn how supervision allows a Verkada access controller to detect cut and shorted wiring

Supervision enables all second-generation or newer access control products to detect if a REX or DPI wired normally open (NO) has been cut or if a wire configured normally closed (NC) has been shorted and trigger a notification, aux output event, or raise an alarm if set as a Verkada Alarms trigger. We also support supervised wiring for alarms which is configured and used separately.

Supervision types

Most access controllers support single end-of-line (EOL) and double EOL supervision. These 2 types of supervision can be applied to REX and DPI sensors wired normally open (NO) or normally closed (NC). The resistors should be placed as closely to the devices as possible to prevent a short or cut in the wire at the end of the line.

Supervised wiring is not currently available for the AC41.

Single EOLR supervision

Resistance	Normally Closed (NC)	Normally Open (NO)
0 Ω	Shorted circuit; trouble condition	Shorted circuit or closed event; alarm activated
1000Ω	Normal state	Normal state
Infinite Ω	Cut wire or open event; alarm activated	Cut wire; trouble condition

Double EOLR supervision

Resistance	Normally Closed (NC)	Normally Open (NO)
0 Ω	Shorted circuit; trouble condition	Shorted circuit; trouble condition
1000Ω	Normal state	Closed event; alarm activated
2000Ω	Open event; alarm activated	Normal state
Infinite Ω	Cut wire; trouble condition	Cut wire; trouble condition

EOL resistors must be 1000Ω.

Wire EOL resistors to your access controller

The resistors should always be installed at the end of the circuit, as close to the sensor as possible. Installing EOL resistors at the panel can inhibit the purpose of supervision.

Single EOLR Double EOL

Setting up EOL resistors in Command

1

In Verkada Command, go to All Products > Access.

2

Select a site from the All Sites dropdown.

3

Select a door and click Settings .

4

Under Hardware, select where the EOL resistor is located. Supervised wiring can be configured under the following sections:

a. DPI b. REX1 c. REX2

5

Next to the Supervised Wiring dropdown, select the correct EOL resistor for the door.

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6

Event tiles for supervised events will appear automatically once enabled.

When enabling supervised wiring, ensure that the resistors are present, or this will lead to false alerts.

Alerts

Supervised alerts are treated like door events, similar to doors forced open. You can configure an AUX output to alert a strobe or alarm of a detected tamper event to deter bad actors. See Configure Access Control Events Alerts to configure EOL resistor alerts.

If a REX is configured to unlock a door when triggered, rather than for egress detection, the door will still unlock if the supervised wire configuration has failed and a full short or open circuit is detected for a NO and NC configurations.

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Need more help? Contact Verkada Support.