Some facilities require more rigorous physical security needs, and your access control solution should be able to support these special applications. Here we cover how to install and configure the Verkada AC41 for man trap and in-out badging.
A man trap is a set of two doors where the first door must be closed before the second is permitted to open, similar to an airlock.
To support this, we must wire the doors to the AC41 in a specific way:
Figure 1: Wiring two doors to AC41 for man trap
By connecting the interior door's lock in series with the exterior door's contact switch, we do not allow the interior door to open until the exterior is closed.
Some doors have a card reader on both sides, and access needs to be controlled in either direction. We can accomplish this in one of two ways:
Option 1: Two Readers, Two Cassettes
Figure 2: In-out badging using two AC41 cassettes and fail-secure locking in dry configuration
Figure 3: In-out badging using two AC41 cassettes and fail-secure locking in wet configuration
We can connect the two readers each to their own AC41 cassette, and connect the lock to both outputs. This way we can distinguish between interior and exterior access events. If wiring using fail-secure locking in a wet configuration, you will additionally need to configure the aux input to unlock the door, which you can do following this guide here.
Note: The NO relays will be wired in parallel to control a fail-secure lock, or the NC relays wired in series to control a fail-safe lock.
Figure 4: In-out badging using two AC41 cassettes and one wet fail-safe lock
Example: Short the NC ports on two cassettes and connect the common ports to the maglock. Leave cassette one in the appropriate wet state, 12v or 24v, and the second cassette as dry or NONE.
Option 2: Optical Wiegand Isolator
Figure 5: In-out badging using an optical isolator
We can connect two readers to the same AC41 cassette using a Wiegand optical isolator. You will need to short the 5V resistors to each data line (orange lines). This saves a cassette, but requires another device and will not allow you to distinguish between interior and exterior access events.