Troubleshooting is an essential skill for those installing as well as servicing electronic access control systems. Although visual observations are an excellent place to start, getting some background on an installation before you even head out is also helpful.
Before you leave the shop:
1. Know which mechanic’s skill set will be best suited for a particular situation;
2. Download installation instructions for the equipment on site;
3. Get some information on the age, and service/performance history of the system (may be on file if you installed or previously serviced the system).
When you do installations, sometimes the troubleshooting begins as soon as the last connection has been made and power is first applied to the system. Click: Nothing happens, (or the wrong things happen.)
Electronic access control systems are comprised of certain essential circuit elements:
- The Power Supply,
- The Wiring,
- The Controls,
- The Locking Device (a/k/a the load)
Access control systems have at least one power supply for the controller, and possibly another for the locking system, and in some cases an additional power supply for a special purpose reader or other device. Sometimes a single power supply will operate everything. I refer to DC (Direct Current) output sources as power supplies, and AC (Alternating Current) sources as transformers. Wall-mount plug-in power sources are convenient and do not require an electrician to install.
Issues can arise when these wall warts are accidentally unplugged or if the receptacle happens to be controlled by a wall switch or may be turned off unexpectedly by well-intentioned conservationist trying to save electricity.
Hard-wired, power supplies have a metal enclosure and can be outfitted with a line cord or an electrician can hard-wire it to a suitable branch circuit. With a metal enclosure, you can put other accessories such as relays or timer modules inside, or you can get a power supply with Fire Alarm interface or battery backup.
Wiring is still used on most electronic access controls.
Standalone Electronic Access Control is one notable exception. These devices have their own integral power (battery or magneto) integral reader or keypad, integral locking device, and integral logic controller. Standalone access has traditionally not been capable of real time alarm reporting, logging, adding and removing credentials or remote release without wiring. Some models require the use of a handheld programmer.
But that is changing with the introduction of wireless network to enable these features One example is the ALARMLOCK NETWORX.
We also can use wireless remote release buttons with certain standalone access controls equipped to accept remote release triggers. Otherwise your access controls will require wiring for power, video/data, control, and switching purposes.
Your power wiring will be for the reader, the controller or the locking device and is a prime suspect as a source of trouble. Assuming you’re power supply is working and properly rated for the application, and your locking device is working, adequately powered, and properly isolated, then your voltage levels may be low due to that old gremlin, voltage drop.
Voltage Drop is present in all circuits, but it is not always a problem. Problems occur when the system design does not take the voltage drop into account when selecting wire gauge, equipment, or equipment locations.
When designing the system, voltage drop calculations should be used as a guide to selecting the correct wire gauge, and perhaps locating power supplies. In some situations, increasing the wire gauge will not be enough and the solution will be to shorten the wire run by relocating the power supply to a point closer to the load.
Voltage drop can become a problem, perhaps an intermittent problem, after the system has been deployed.
Occasionally when installing access controls, things will not go the way you thought they ought to. Some call it a “bug” or a “ghost in the machine,” but your equipment is misbehaving. There...