A large percentage of any access control project is in the installation, especially the wiring. This is one of the reasons behind the popularity of wireless locks in our industry. But most customers prefer the traditional wired approach for their critical access control doors, and with newer control panels the idea of “embedded lock power management” is helping to save on costs.
In previous generations of access controllers, the controller did not switch the electronic lock’s circuit directly. The panel’s small on-board relay was used as a pilot relay to switch a larger relay, located on an external board. This external relay was then used to energize or de-energize the actual locking device. Having this external device in the circuit helped to protect the control panel against damage due to lock inrush current and other transients. The external board also had two other jobs – to provide individual fuse protection for each lock circuit, and, to provide a means of accomplishing fire override on a per-lock basis.
Fire override is obviously important from a life safety perspective. Upon an alarm signal from the building’s fire alarm system, selected locks must revert to their “fail safe” position, allowing free egress. This interlock must be accomplished in a manner that does not involve any software or firmware – it has to be “hard-wired” into the circuit or device. In some locales an additional fireman’s “key switch” override is required – when the main fire alarm signal is deactivated, locks must not go back to their locked positions until a fireman activates a manual key switch, signifying that the building is all clear.
Lastly, this external board normally featured socketed relays, to help reduce service costs. It’s much easier to replace a single relay than to replace an entire board.
But these external boards add tremendous cost to an access control project, not just in equipment cost, but in wiring labor and also in panel real estate required. Every lock output needs to be wired up twice – first from the controller to the external relay board, and second, from the relay board to the actual locking device. And in some cases a separate enclosure may be required for the board, or, the lock power supply enclosure grew in size to accommodate the boards.
To help reduce these costs, the idea of “embedded lock power management” was introduced. Basically it means taking all the functionality of these external relay boards, and adding it directly onto the access controller, eliminating the need for the external board. Duplicate lock output wiring is eliminated, and the whole system becomes much easier to maintain and troubleshoot. The access controller must have individual protection on each lock output circuit, and must have a means to accomplish fire alarm interlocking that does not rely on the controller’s firmware. And, the controller must be sure to feature socketed relays, to keep repair costs down. In some cases the controller can even have two distinct lock power feeds, with the ability to select which one to use on a per lock basis – for example, a 12V and 24V feed can be used for the controller, and at each lock circuit you can choose between a 12V and 24V supply voltage.
Embedded lock power management – give it a try. The end result is a more streamlined installation, using less panel space, and, you’ll enjoy tremendous installation savings.
Let us know if you’ve had some experience with this method of installation.