Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: TUESDAY, December 20, 1994 TAG: 9412200069
SECTION: EXTRA PAGE: 3 EDITION: METRO
SOURCE:
DATELINE: LENGTH: Medium
This is the second of a two-part series. In the first part, I introduced PLC-based home control and described several types of controllers. This week I'll summarize the full range of receiver modules. Recall that the most popular receivers are the plug-in lamp and appliance modules. However, many other types are available - each designed for a specific purpose.
For example, to control a permanent fixture such as an overhead light, you can choose from a variety of PLC-compatible replacement wall switches. Dimming, non-dimming and three-way versions are available. If you can handle a screwdriver, installation is straightforward; you can swap switches in less than 10 minutes. The PLC wall outlet (functionally the same as an appliance module) is not as easy to install, but only because the heavier electrical wires are more difficult to manipulate.
Have you ever had to grope in the dark to turn on a basement or attic light? A new screw-in PLC receiver provides a convenient way to remotely turn on a pull-chain light fixture. Simply insert the receiver between the bulb and the socket. It can handle bulbs up to 150 watts.
Heavy-duty plug-in modules make it easy to control 220-volt appliances such as swimming pool pumps and window air conditioners (up to 20 amps). One company even offers a PLC-compatible relay for electric water heaters. Rated at 40 amps, it must be wired directly to your water heater, preferably by a licensed electrician. In-line receivers are also available for ceiling fans and other special applications.
Perhaps the most flexible PLC receiver is the appropriately named universal module. It's basically a single-pole relay packaged in a convenient plug-in housing. You can use a universal module to operate just about any low voltage load including sprinkler valves, an automatic voice dialer or an electric door strike. There's even a version designed especially for motorized window coverings.
You can also use a universal module to trigger macros or events in another control system. For example, most security panels have an auxiliary input for remote arming. One company makes a digital thermostat that can be switched in and out of setback from a universal module. By adding a PLC telephone responder, you can call home to adjust the temperature before leaving the office.
You don't have to purchase a new thermostat to control the temperature via PLC. A thermostat kit is available that will work with any thermostat. It consists of a special heating element, which mounts just below your thermostat, and an appliance module. When activated, the added heat tricks the thermostat into setback, causing the room temperature to drop by 5, 10 or 15 degrees (selectable).
For the serious do-it-yourselfer, special-purpose receivers are available with either four or eight independently controlled relays in a single enclosure. Relay boxes are ideal for automation projects with a large number of low voltage loads - for example, heating and cooling equipment, automatic zone control dampers or a multi-zone irrigation system.
To receive a list of companies that manufacture PLC receiver modules, switches and special-purpose receivers, please send $1.50 and a self-addressed envelope to David Butler F-439, Department TWN, 14713 Pleasant Hill Road, Charlotte, N.C. 28278-7927. The list includes toll-free phone numbers and a summary of each company's products.
Reader Tip: In order to optimize TV reception, unused antenna or cable outlets should be "terminated" with an end-of-line resistor. Terminators cost less than $1 and are available at any electronics store (e.g., Radio Shack 15-1144).
by CNB