Powering Up Access Control Systems

Nov. 1, 2006
If an access control system involves more than a single door, a single power supply won't suffice.

Power supplies are an important part of any electrical access or security system. The power requirements for an access control system are therefore typically divided into two categories: power for the controls/readers and power for the locks.

In reality, the power is used for several purposes, depending on the system. Power will be required for:

Readers: Card readers usually require clean power at precise voltage and current. Some readers provide some from of internal regulation, as an attempt to prevent fluctuations which disrupt the reader’s proper operation.

Controllers: Hard-wired access control systems (as opposed to standalone battery powered ones) generally require an external power supply for power. Some system manufacturers provide integral power supplies.

Communications: Access systems which involve multiple doors and proprietary dedicated networks frequently require that power provided to ‘hold up’ the network. Although this power is extremely low current, it must be highly regulated and filtered against noise and interference.

Locks: All electric locking hardware requires power. In the case of electromagnetic locks and other failsafe type equipment, the power must be available in order for the locking device to be ‘locked’. Fail-secure locking devices require that power be applied to ‘unlock’. Electrically actuated trim such as outside levers used with exit bars and mortise locks use power to switch a solenoid in the trim, thereby enabling the lever so that the lever will actuate the associated locking mechanism.

Frequently you will be able to use a single power supply for a system, but if your system involves more than a single door, or uses a specialized locking device or reader, a single power supply won’t suffice.

For example, some readers require a higher capacity power supply in order to achieve extended read ranges.

Another situation would be if you have to run wiring over distance to reach a door location, the power required by your system components and the voltage drop occurring in your wiring will become a critical issue.

Many specialized locking devices require high inrush currents, or will produce what can be generally called ‘electrical noise’, which can be harmful to other components in the system, and otherwise affect the proper operations.

So as often as not, multiple power supplies and separate wiring will be used for the system.

Experienced system designers will anticipate such issues and provide adequate power supply resources initially rather than try to retrofit them to solve system performance anomalities which will occur once everything is hooked up.

Since many door control systems will involve life safety issues (that is they are required to provide safe egress for occupants and emergency entry for responders), power supplies may be obtained with features which allow them to be connected to emergency and fire systems.

The term “Secondary Power Supplies” refers to additional power supplies incorporated into a system. They may be used to augment the primary supply when power requirements exceed the capacities of the primary. They may be situated remotely from the primary power supply in order to avoid voltage drop and effectively “distribute” power. They may also be incorporated to provide redundancy to a system, so that if a primary power supply fails, there is backup. Secondary power supplies are also used to upgrade older installations where revised or new codes mandate additional annunciation.

This month’s product gallery offers a small sampling of power supply products available for access control systems.

Altronix StrikeIt™

StrikeIt™ Panic Device Power/Controller Series is one of the new series of branded integrated products from Altronix. It is designed specifically to handle the high power demand required to activate panic device egress hardware.

StrikeIt™ will operate up to two 24VDC panic hardware devices simultaneously. It is designed to handle the high current surge that panic hardware locking devices demand. A programmable timed lock release feature ranging from one to 30 seconds, supervised lock outputs and two programmable fire alarm disconnect options are all included, along with simultaneous 12VDC and 24VDC constant power outputs for access control accessories. Two form “C” follower relays and two form “C” delayed momentary relays which follow the lock outputs are provided for activation of automatic door operators. On-board circuitry facilitates stand-by battery charging.

For more information, call 1-888-258-7669, e-mail [email protected] or visit www.altronix.com

AL600ULX Power Supply/ Charger

The Altronix Model AL600ULX power supply converts an 115VAC 60Hz input, to a 6 amp of continuous supply current @ 12VDC or 24VDC non-power limited output.

It meets the following agency listing requirements:

  • UL Listed for Access Control Systems (UL294), Power Supplies for Fire Protective Signaling Systems (UL1481).
  • CUL Listed - CSA Standard C22.2 No.205-M1983, Signal Equipment
  • CSFM - California State Fire Marshal Approved
  • MEA - NYC Department of Buildings Approved
  • FM Approved
  • NFPA 72 Compliant

    AL600ULX Features/Specifications:
  • 12VDC or 24VDC selectable output.
  • 6 amp of continuous supply current.
  • 115VAC 60Hz, 1.9 amp input
  • Filtered and electronically regulated outputs
  • Short circuit and thermal overload protection
  • Built-in charger for sealed lead acid or gel type battery backup
  • Maximum charge current .7 amp.
  • Zero voltage drop upon transfer to battery backup
  • AC input and DC output LED indicators.
  • AC fail supervision (form “C” contact rated @ 1 amp 28VDC).
  • Low battery and battery presence supervision (form “C” contact rated @ 1 amp 28VDC)
  • Lifetime warranty

The enclosure accommodates up to two 12VDC/7AH batteries. Dimensions are 5”H x 13”W x 3.25”D, with half and three-quarter combination knockouts.

Honeywell Power Products

HPP’s Access Control Power Supplies offer significantly expanded capabilities. The core supplies, HP300ULX, HP400ULX and HP600ULX, are available in three power output levels: 2.5A, 4A and 6A. By adding the HPMOM5 fire door controller to the supply family, the HP300ULM, HP400ULM and HP600ULM Series complete the power supply package.

Adding the HPACM8 access control card to the base supplies makes the HP600ULACM8 capable of powering the most demanding applications. This power supply family has a wide range of applications for access control systems that require door control with additional power.

HPP Access Control Power Supplies carry both UL and ULC ratings for fire, access control and intrusion systems and have a large enclosure to ease wiring. They feature circuit-breaker battery protection, AC input and DC output LED diagnostic indicators, AC fail and battery monitoring contacts to aid in supervision, and a built-in charger for sealed lead-acid or gel-type batteries. In addition, the Power Supplies offer a filtered and electronically regulated output, and an automatic switchover to standby battery when AC fails. All of the power supplies are 12vdc or 24vdc field- selectable.

The HPP HPS312CX is a switching power supply/charger that converts low-voltage AC input into 6, 12 or 24VDC at 3.0A of continuous supply current. The HPS312CX also comes kitted with an HPP HPT2450 plug-in transformer, a 5 AH battery, a steel enclosure, and connecting hardware. This general-purpose power supply has a wide range of applications for access control systems that require additional power, and will operate with a non-linear power source.

For more information, call 800-345-6770 or visit www.honeywellpower.com.

Locknetics 505 Power Supply

The 500 Series power supplies are available in three models each are UL Listed as a General Purpose Power Supply. The 505, 510 and 515 Series all feature low voltage DC, regulated, filtered power supplies with a built in battery charging circuit and are designed to provide easy system interface with Locknetics locking devices, station controls and consoles.

A NEMA Grade 1 approved enclosure is universal throughout the line, measuring 12”x12”x4”. The 500 Series provides a built-in battery charging regulated, with a built in battery charging circuit.

Standby battery kits (SBP1 or SBP2) can be added to the 505 Series power supply at the factory or in the field.

A key lock cover, power line cord and emergency interface relay module (EIR-5) are available as factory installed options.

For more information, call 866-322-1237 or visit www.locknetics.com.

Security Door Controls

The SDC 631RF Power Supplies have been developed specifically to support electric locks and access controls, with high performance, heavy-duty circuitry for inductive loads and multi-door applications. The modular design is built around several different application control modules to meet he specific needs for virtually any electric lock system.

SDC power supplies are designed to provide a well-organized installation for individual or multi-door systems that may include locking devices, access controls, station controls and consoles for remote control, annunciation and fire/life safety system interface.

SDC 600 Series power supplies are manufactured according to ISO 9001 certified quality standards. Tests are conducted according to tough UL 1481 criteria for specific use with access controls, fire and burglary applications.

Ten different, individually fused door control modules are available for any application. Time delays, latching relays and multiple station circuit breaker modules are available for custom configuration in the field or at the factory.

Specification of the UR Universal Access Hardware Controller provides for six standard DIP switch selectable system and mantrap variations for multiple door systems.

The output filtering stabilizes the DC output voltage and eliminates AC line noise. The solid state regulator maintains the selected output voltage at 12VDC or 24VDC regardless of the output load changes, including battery charging.

The AC input is protected by a fuse and secondary DC output is protected by auto resetting poly fuse.

A separate PTC protected, battery charger output provides 13.5VDC or 27VDC.

Batteries are automatically disconnected from the secondary output circuit when the voltage decreases below 70 percent. This ensures batteries are capable of recharging.

An LED System Status Indicator is included.

Amber means AC and DC voltages are OK

Green indicates - no DC output.

Red means no AC input, powered by batteries.

Additional features include:

Isolated Charging Circuit: While the charging output is 13.5VDC or 27VDC, the secondary output is unaffected and precisely maintained at the selected 12 or 24VDC. This ensures system components are powered by their specified voltage.

The secondary output current is maintained at the full 1.5 Amp capacity and is not de-rated when charging batteries.

Class 2 Outputs: Where permitted by code, conduit is not required when using Class 2 outputs.

Emergency Release Input: The Fire/Life Safety emergency release input is standard on all SDC power supplies, field selectable 12 or 24VDC.

The output is field selectable for 12 or 24VDC output. Large Heavy Gauge Enclosure Model 631RFA is housed in a 16 gauge, 16”W x 14”H x 6.5”D cabinet large enough to accommodate several additional modules and six 7 Amp hour batteries with plenty of room for wiring.

For more information, call 800-413-8783 or visit www.sdcsecurity.com.

About the Author

Tim O'Leary

Tim O'Leary is a security consultant, trainer and technician who has also been writing articles on all areas of locksmithing & physical security for many years.