Starting at the door...credentials can be cards, fingerprints, keypads, handprints, iris templates, facial templates, cell phone credentials, or other credential technologies. Smart cards, proximity cards, and keypads are still very popular in many systems, but phone credentials are increasingly becoming important. Phone credentials can offer higher security than older card technologies.
The reader is typically the front end of the system and is located on the entrance side of the door. With secure systems, the connections for the locking hardware are not brought to the reader directly. The reader typically sends back data to a control panel that is located in a secure area, controlling the power to the locks securely. There are less sophisticated reader devices available for lower security applications. Devices such as stand-alone keypads can be cost-effective and easy to install in basic applications. Professional smart card readers also offer added security over stand-alone devices, especially because smart cards are not easily duplicatable and because they connected to a door controller remotely.
The door controller is a device that can accept signals from one or more readers and can make a door lock unlock when proper credentials are used. Usually, the door controller is housed in an electrical enclosure and placed on the wall or secure location. In an IT-based environment, these controllers can be placed in a secure server room with wiring running from the controller to the reader and the locking hardware. The door controller receives the data from the credential from the reader and uses this data to determine if the credential is valid. There is a credential lookup process that goes on against a database that is stored on the controller, or some controllers can contact a database that is hosted on a remote server or cloud database. The controller is the brains of the system and may provide additional door functions in addition to the validation of credentials. These features may include automatic door unlocking by schedule, lockdown features in the case of a panic situation, audit trailing that tracks who came in what door at what time, access level permission control that determines who can come in a specified door at a particular time. A door controller may have automation features that can kick off other events to occur like turning on lighting when a card is swiped to enter a room. Door controllers can be typically programmed through networking connections using software, but may also be programmed by other means, like touchscreens. Some door controllers include programming functions at the reader or programming by cell phone application, like the HighpowerOne controller.
There are many types of locks. The type of lock selected for a door is usually based on the door construction and security requirements. Electric strikes and Electromagnetic Locks are two popular types of locking mechanisms, but there are other more specific types. Lock types are further described below.
For controlling latches like typical door lever cylindrical locks, some types of deadbolts, and non-electrified panic bars, the electric strike is a good choice. There are standard electric strikes for latches (like door lever latches) but also universal strikes that can be used with bolts and mortise locks. Typically, strikes are fail secure, in that they stay locked when they are unpowered. Once power is supplied to them they unlock. This may not always be the case as many strikes can be changed over mechanically to also operate in a fail-safe mode for special applications, where power is required to keep the device locked. Strikes provide a secure way of controlling the latch of a door especially when a plate is used to cover the door latch and strike assembly. They are especially useful when controlling external doors on a building since they can stay locked without power. They are also useful in fire-rated door applications as many strikes can be ordered in fire-rated versions that keep the door and frame in code when using a rated strike. Strikes work in conjunction with the existing door hardware. In the case of a typical storeroom function lever, the lever on the inside of the building is unlocked and can always be turned to get out. Turning the level on the inside retracts the latch allowing people to leave. On the outside of the door, when the strike is powered, the latch on the door does not need to be retracted. The strike allows the latch to pass through the frame once the strike is energized without turning any handle. In the case of a panic bar, pressing the bar will always retract the latch to get out, but coming in the strike would have to let the latch pass through the frame allowing people on the outside to enter. Strikes can also be used in conjunction with stand-alone devices such as electronic leverset in the case where an additional local override may be required at a door.
Electromagnetic Locks (Maglocks)
Electromagnetic Locks are used for applications that are difficult to install an electric strike, for high-traffic door applications, or for applications where binding of a mechanism would cause fire safety issues. Electromagnetic locks are large electromagnets that hold a door closed with magnetism. Because they do not have moving parts, they can last a long time in high-traffic applications. They can also be used in safety-sensitive applications when used with proper release hardware, as they can’t bind under door pressure. Electromagnetic locks are typically installed in the upper opening corner of a door and frame but can also be mounted vertically at the opening side of the door for higher performance applications. Vertical custom housings can be used to accommodate multiple maglocks which hold the door at various points to prevent door flexing when the door is under physical load. Maglocks come in both single door and double door versions. Double door versions allow the locking control of entrances that have double door configuration. Maglocks are typically fail-safe in that they require power to generate the magnetism that creates the locking action. Maglocks are in widespread use on aluminum storefront doors and doors that have frames filled with construction materials like concrete. These types of situations have hardware that is challenging to adapt to an electric strike.
When using an electromagnetic lock, the existing hardware does not work in conjunction with the lock. You may have a door lever or a pull handle on the door, but this hardware works independently of the maglock. Because of this, fire codes require that two additional pieces of hardware get installed with a maglock to ensure safety. A button to cut the power to the maglock is required that is labeled PUSH TO EXIT. This button normally includes a timer, typically a mechanical timer, that keeps the door unlocked for 15 or 30 seconds based on local code. In addition to the push to exit button, either a motion sensor or a panic bar with a switch installed to cut the power to the maglock needs to be incorporated. The motion sensor is interchangeable with the crash bar according to fire codes. Typically a motion sensor is preferred because it is passive with no parts to wear out and is often less costly. Panic bars with switches are also used in maglock systems when having difficulty focusing a motion sensor for the situation. The benefit of using a crash bar is that the door may not become unlocked inadvertently should someone step near the door on the inside of the facility.
Power supplies are used to power the locking device and may also provide additional logic functions that a certain locking device may require to operate properly or to code. Strikes and maglocks may be operated on simple power supplies, such as a plug-in wall transformer but often full-frame enclosed power supplies are installed in a system. Full frame power supplies can connect to a mains high voltage connection and may provide features like battery backup. Because electromagnetic locks unlock when power is lost, the battery backup feature in a power supply may be important with high-security applications. There may be fire code situations where a battery backup system with a maglock may not be allowed. Consult with your local fire authority before implementing a battery backup system.
Doors sensors are often integrated into the lock itself but can also be separate small devices that are added to doors. A Door position switch is a switch that opens and closed based on the position of the door. Signals from these switches are often routed directly to a door controller. As an example, the door controller can detect when the door is closed after using a credential to immediately lock the door. This is a feature called anti-tailgating. Door position switch signals can also be routed to software to monitor the state of the door remotely. Door ajar warnings may be generated after a certain amount of time of leaving the door open on some systems using this signal.
With the electric strike, latch monitors may be available. Similar to a door position sensor, the latch monitor can monitor the position of the door. They can also monitor the state of locking by detecting if the door latch is seated properly in the strike.
With maglocks, magnetic bond sensors can be included. These are sensors on the maglock that can detect if an obstruction is placed between the lock and the lock’s armature (the metal component that is mounted on the door that the lock uses for magnetic holding). With a bond sensor if an obstruction is added to the lock to prevent it from locking to full strength (like placing tape or debris on the lock face) the bond sensor can detect this obstruction and warn the access control system. This sensor is similar to a door position switch in that it can monitor if the door is securely locked or not.
Automatic Door Operators
Automatic Door Operators are becoming more common in the age of COVID-19. Door operators not only can open a door for physically challenged people to more easily enter but they can also be used to implement touchless door operation. With automatic operators, they can be used with access control to require that a credential be presented to unlock the door. In addition to the unlocking function, access control systems may also open the door automatically when the credential is presented. The process of unlocking the door and then opening automatically may be one step, just using a credential, or maybe two steps. With the two-step approach, a credential may be used to unlock the door for a normal manual pull but the credential may also enable the ability to swipe a touchless sensor to trigger the automatic opening cycle. This is used for systems where not everyone entering needs to use the automatic door opening feature.
Door controllers typically use a standard Ethernet network connection but can also use serial RS-485/RS-232 connections. Some advanced controllers may also include WiFi for networking or other types of wireless connections like Bluetooth or LoRa. These connections are used to interface the door controller to software or cloud-based database. With software systems that run on a PC system, the PC server can push updates to the panel that may include new credentials added to the system, or other information such as schedule updates and status checks. On cloud-based systems, the remote cloud system uses internet connections to push data updates to the hardware.
Software for door controllers may be either PC-based (traditional) or cloud-based. Some of the cloud-based systems may be convenient, but many of these systems require subscriptions based services. PC-based systems give the owner of the hardware full control and ensure that the system can keep operating should the vendor of the system go out of business or suffer an outage. Cloud-based systems offer convenience though, in that the software, hardware, and network connections for the access control do not need to be maintained directly by the customer.
Newer systems may combine the functions of the reader and the controller into one unit. These hybrid controllers may be chosen mainly for ease-of-installation and to reduce wiring requirements. Many cloud-based stand-alone access control devices combine the reader and the controller into the reader section. You want to be cautious of these types of systems as you are often bringing the lock power wires to the unsecured side of the door, which may cause security concerns. Some devices are integrated up to the point with the reader and controller in one device, but they keep the lock signals at a separate module on the secured side of the door. Even these types of devices may have a security issue because many of these types of devices also require a network cable connection which can expose the network to the unsecured site of the door. Exposing network connections is a very serious issue and can be even more critical than physically entering the facility. The best examples of these combined controllers are ones that use Bluetooth to accept a credential from the cell phone but are placed on the secure side of the door. Using Bluetooth to send the credential wirelessly can prevent someone from physically compromising signals at the reader.
For questions in designing your access control system, contact Shop&Lock via email at email@example.com. We can help design a system to address your needs or just answer questions about individual components that you may need for retrofit. Visit us also on LinkedIn.