ACCESS CONTROL, WHEN YOUR SHORT OF WIRES

BY: Don McClatchie

          Access control is in use all around us, from the simple key and lock to the more complicated electronic remote access control. Electronic access control relies on wires to convey the commands to open gates, or unlock doors. Access control also extends to industrial control, where a wired electronic interface controls manufacturing or processing machines allowing personnel to operate the machines at a safe distance or in a common location to improve efficiency.

          With industrial controls, it is normally easy to run wires wherever they are needed because the buildings and areas are open and no one would complain about some wires or conduit running from one place to another. However, with access control particularly in private residences or public buildings the wiring for access control must be hidden or at the least it must blend in with the decor. That usually means that the wires for access control are buried or hidden in walls, under floors or in the sealed recesses of the building.

          These control wires are normally installed ahead of the access control equipment so they can be sealed up, out of sight, and often other companies and installers do the work and if the installers fail to put enough wires in the walls or under the concrete to operate the equipment, you come up short of wires to install your access control equipment.

          At this point you have two options, break into the walls, dig up the concrete or find something that will get your control signals through using the available wires. This choice is usually determined by the cost or the time it takes to correct the problem. If it is cheaper to run new wire, then that is the best option, however if the cost of doing so is prohibitive, then you need to find equipment that will carry multiple signals on the wires you have and give you the control you need.

          If your access control needs remote relay contacts to open gates or turn on lights, then you can use the IP4x4 to get up to 4 contact relays onto one pair of wires. This unit will work up to distances of 5000 feet of wire and it is resistant to electrical interference.

Remote Control over IP Video

Remote Control Twisted Pair

          The IP4x4 uses a dual sinewave signal to carry the relay control signal so electrical impulse noise will not interfere with the control. It comes as a set of two units that are identical in operation, one unit goes at each end of the wire pair. When you operate a switch attached to the “SWITCH INPUT” on one unit, at the other end of the wire pair the other units “RELAY OUTPUT” closes a relay contact in response. In this way, the access control contacts are relayed down a signal wire pair. Up to 4 relays can be operated with a single set of IP4x4 units.

          With two pairs of wires you can have two-way relay control with the same set of units. Each unit features 4 switch inputs, and 4 relay outputs, for a two-way 4 relay control on two wire pairs. This makes the IP4x4 perfect for gate control and industrial uses.

          For high security, the system has an alarm output relay that monitors the communication path between the two units and if the wires are cut or the units stop communicating for any reason, the alarm relay will activate. By monitoring this feature, you can have full confidence that the system is operating and that you have full control over the contacts. In the event of a power or communications failure on the transmit end, the receiver end of the system will remember the relay positions and maintain them, so the relays do not drop out if communication is interrupted and at the same time the alarm relay activates to alert you to the communication loss.

          Use this unit when you come up short of wires and the cost of digging up concrete or breaking into walls is prohibitive or if you don’t have the time to wait for heavy construction and the finish work to be completed.

          If you are using an IP camera, you can use this system to add access control using the network twisted pair wires 4,5,7,8 as the signal path. This is block diagram of how you can use the IP4x4 with an IP camera. This system will work with P.O.E. if the power is on the IP data wires. Wires 4,5,7, and 8 are used for remote control signals only.

IP4x4 Block

Call 800-235-6960 or CLICK on this link to see more information.