The programmable logic controller (PLC) allowed for the integration of three basic electrical systems: lighting, drapery and audio. It also allowed for all of the systems to be controlled from one common wall station, thus eliminating the conventional switch wall clutter.

Programmable Logic Controller Application

Eugene Kowch | P.I.D. Consultants Inc.

Programmable Logic Controller Application
By Eugene Kowch, P.I.D. Consultants Inc.

The programmable logic controller (PLC) allowed for the integration of three basic electrical systems: lighting, drapery and audio. It also allowed for all of the systems to be controlled from one common wall station, thus eliminating the conventional switch wall clutter.


A builder of a penthouse suite decided he did not want conventional electrical switching on the walls. The reason for his decision was obvious; he did not want electrical switch wall clutter in the new penthouse he was building. The suite would have over forty lighting circuits, fifty-four motorized drapes and seven volume control units, one for each room. He could only imagine what the walls would look like in this penthouse if the electrician installed conventional electrical switches.

It was decided that the lighting controllers would be Lutron Grafik Eyes, drapery motors would be activated by Somfy 3N1 controllers and room volume control would be via Knoll Systems digital VC220PM units. The Lutron Grafik Eyes were selected for lighting control because of their dimming capability and scene selection feature. Also, they are modular, one Grafik Eye per room. But the real reason for selecting the Lutron system was for their 10-button wall stations that fit in a single gang wall box. This type of wall station would solve the builder's electrical switch wall clutter problem.

For this 10-button wall station to control the drapes and audio, as well as the lights in the various rooms, required a programmable logic controller in the loop. The programmable logic controller (PLC) would be the center of all the communications between the above systems. For the PLC to communicate with the Grafik Eyes, a RS232 interface was incorporated. This interface allows the PLC to monitor every button push on any 10-button wall station. For the PLC to activate the drapery motors, it used it's own discrete output relays and hardwired via telephone wires to each drapery controller. The volume control units would connect to the PLC via the Knoll Systems VCI 28 interface.

The 10-button wall stations were strategically placed throughout the penthouse suite. The functions on each button were programmed to be exactly the same on every wall station. The first three buttons on the right side of the wall station were lighting scene control. The fourth button was for volume control and the fifth button on the right side was for all lights off in the room. The four left side buttons were programmed to raise and lower the drapes in the room. The fifth button on the left was programmed with a unique feature, 'Exit'. By pushing this button the lights in the room you are in go 'off' and the lights in the room you are going to go 'on'. The large buttons at the bottom of the wall station allowed for raising/lowering the audio or light levels in the room.

The system was implemented in the penthouse and the builder was very happy with the results.

The programmable logic controller (PLC) allowed for the integration of three basic electrical systems: lighting, drapery and audio. It also allowed for all of the systems to be controlled from one common wall station, thus eliminating the conventional switch wall clutter.


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