The Verkada AC41 access controller is able to provide power to certain locks as long as their in-rush current does not exceed 350mA at 24V or 700mA at 12V. The inrush current, used to initially magnetise the lock can exceed the operating current and is sometimes not listed in the datasheets. If the requirements exceed the power that the AC41 can provide, the door will not be able to lock and the AC41 could become damaged.
Maglocks and crash bars always require using an additional power supply or access power controller, do not power them via the AC41 access controller. This article will detail a few of the options available.
WARNING! – ENSURE POWER IS DISCONNECTED FROM THE AC41 AND LOCKING HARDWARE BEFORE WIRING READERS AND OTHER DEVICES. FAILURE TO DO SO CAN DAMAGE THE AC41.
Using an Access Power Controller
This option uses an external Access Power Controller, such as the Altronix AL600ULACM (widely available in the US) or the Hfeng Access Control Power Supply Controller Switch. (available in EMEA, pictured below).
The AC41 will run Dry (the toggle on the left side of the cassette is configured to None), and will connect the NO and COM ports to IN and GND respectively (the IN port is sometimes labeled as PUSH, as per the picture above). The Access Power Controller will then use its NC and COM ports to connect to the maglock.
Manual release in case of an emergency
As maglocks are powered constantly, fault tolerance needs to be built in the system, in order to permit exit in case of any emergency, without relying on the system itself. This is done by installing a break glass button in the vicinity of the REX, that can be smashed in case of an emergency, effectively breaking the circuit and allowing for exit. This button needs to be installed in series with the Access Power Controller and Maglock.
Furthermore, depending on the local regulations, the Fire Alarm system might need to be set up in order to automatically drop power to the Maglocks. This is done by wiring the Fire Alarm Control Panel (FACP) Trigger Input in parallel with the AC41s own connections to the APC.
In the event of the FACP detecting a fire, it can be programmed to set off the auxiliary relay (or series of relays), which in turn will instruct the Access Power Controller (APC) to drop power.
Please note that the Verkada AC41 does not have a dedicated FACP input, this needs to be wired into the Access Power Controller. Furthermore, the location of the FACP Trigger Input might vary depending on the APC used, and it is on the installer to read the appropriate documentation and understand the proper wiring configuration.
Using a regular Power Supply
In the case no Access Power Controller (APC) is available, one can use a regular Power Supply Unit (PSU), such as the Fortessa DC Boxed Switch Mode Power Supply Unit, and an additional 12V/24V relay module (an example pictured below).
The wiring required is displayed below (note the Glass Break required for manual egress in case of emergency, if the system is not responsive):