Home Automation Controllers

Home AutomationControllers

In this chapter, you will learn about

  • The features of home automation controllers
  • The communications technologies used by controllers
  • Configuring a controller

At the heart of an integrated home automation system is the controller. It is like a conductor of an orchestra, directing when each instrumental section plays, how loud or soft they play, and so on. In a similar manner, the controller of a home automation system directs when each subsystem is activated and provides its settings, such as the volume, operating patterns, and the like. The home controller creates the total experience for the occupants of the home, just as the orchestra creates the total experience.

A home automation controller is the integrator of the independent systems in the home. It pulls the home’s subsystems into a single integrated system and through its control settings and programming manages a home’s total environment.

This chapter focuses on the different types of home automation controllers and their components, functions, and configuration. Essentially, all home automation controllers perform the same basic tasks. However, it is how they go about performing these tasks that this chapter is about.

Controller Features and Characteristics

The primary feature of any home automation system controller is control. More specifically, this means the controllers capability to interface, interact, and communicate with the different subsystems in an automated home.

The true benefit of installing a controller in a home system is that it consolidates the functions of the separate subsystem controllers into a single interface for the homeowner. In home subsystems such as lighting control systems, Heating, Ventilating, Air Conditioning (HVAC) systems, security systems, distributed audio/video systems, and any other systems a home may have installed, each usually has its own separate controller with unique user interfaces. Often, the convenience gained from each subsystem is lost in the complexities, and possible overlapping, of the controls.

Integrating the subsystem controls into a single home control system means there is only one user interface for the homeowner to learn. For example, a single button on a room controller might dim the room lights, turn on the audio, turn up the room heat, and turn on the outside lighting. Or a button labeled “Outta Here” could turn down the heat, lower the house lighting, and arm the security system. With independently controlled subsystems, each of these actions would require the homeowners to take several steps; they would need to remember each step instead of using a single button, leaving nothing forgotten. The capability to set whole house environmental scenes through the push of a single button is perhaps the biggest advantage a controller-based home automation system provides.

Hardware and Software Based Controllers

Home system controllers can be either hardware-based or software-based. However, in either case, the system controller involves a computer microprocessor. A home system controller doesn’t have to be a separate device installed in a control box or panel in a central location along side of the structured wiring distribution panel. The controller can be a home PC running home system control software.

Hardware-Based ControllersHardware-based controllers are specialized devices with a microprocessor for processing inputs and providing control. They are equipped with relays, input and output jacks, a variety of optional communication ports and have embedded processors to provide stand-alone functionality for the home control system.

Hardware system controllers provide a variety of features, including:

  • CommunicationsA home control system controller typically has relay or contact closures, infrared (IR) ports, radio frequency (RF) port, serial RS-232 and RS-485, Universal Serial Bus (USB), or RJ-45 connections for Ethernet that are used to communicate with local controls, devices, and subsystems directly.
  • Macros, modes, and scenesThe better system controllers have the capability to set the operating levels and functions of different combinations of local devices to create a local scene, also called a mode or a macro.


    A macro is a setting on a controller that can be enacted with the press of a single button to send numerous commands and settings to several different devices as a part of a single control sequence.

  • Multiple-zone controlSystem control units have the capability to control devices in more than one room or zone of a home.
  • ReliabilityMany types of hardware-based system control units have the capability to modulate the signal strength to overcome interference on the communications lines.
  • Remote accessQuality home system control units also provide the capability to access the control system remotely, using the phone line, remote portable computer, modem, or over the Internet via TCP/IP.
  • User interfaceA home control system is typically operated through either local keypad control, touch screens, or through software running on a web-enabled device such as a PDA or PC.

Software-Based Controllers

Several types of home control system software are available that can be installed on a PC and connected to the home network, be it the power line control (PLC) type or Ethernet home network.

Many of the home automation control software products available are designed to work with Ethernet networking, regardless of the transmission media or technology in use. Some are specific to certain media, such as PLC, but the better systems are designed to work over any hard-wired home network operating on Ethernet protocol.

PLC software products interface to the AC powerlines using Electronic Industries Alliance/ Telecommunications Industry Association, or EIA/TIA (RS) 232 or 485 serial interfaces and typically use a DB-9 connector or a USB interface. Using one of these serial connections, the PC is connected to a PLC interface that provides the link to the AC electrical lines and any other PLC devices connected to the AC system. Some software control systems provide an IR interface to allow the PC to control devices with a line-of-sight connection.


A home system controller, as shown in Figure 39-1, can be connected directly to the devices it controls or connected for communication with the subsystems it is sending control commands to. There are four possible ways to connect the controller to the devices or subsystems that it must communicate with:

  • Hard-wired
  • IP-connected
  • PLC
  • Wireless

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    Figure 39-1: A home system control panel

Photo courtesy of Crestron Electronics.

Controllers communicate with devices and subsystems and their control modules in either a one-way or a two-way direction. A home system controller may communicate with the lighting system using a one-way direction, but it may communicate with the room control requesting a lighting scene change using a two-way direction. When the room control requests the scene change, the controller signals the lighting control module to activate a preset lighting configuration (one-way) and then notifies the room control (two-way) to confirm the change has been made.

One-way communications are used to transmit control signals to devices or subsystem controllers or to receive signals from subsystem controllers. The home system controller may have only one-way communications with a subsystem controller, which then has two-way communications with the devices under its control.

Two-way communications are used to send or receive command requests to and from subsystem controllers and room control devices and then to transmit command signals and status information to these same devices.

When the controller issues commands to a subsystem controller, it must use the signal format and coding scheme understood by the subsystem. Most robust control systems are able to communicate in a variety of ways including relay/contact closure, IR, RF, RS-232, RS-485 and TCP/IP. So, in some ways, a home system controller also acts as a translator and interpreter between the various components and subsystems connected to it.

Hard-Wired Controllers

Some subsystems, such as telephone, security, and surveillance systems, have their own unique signal formats that require a direct connection to the controller and to a subsystem module. The subsystem module can either be integrated into the controller or act as a stand-alone controller connected to the home system controller. It receives, interprets, and transmits signals in the proper format. The subsystem module can also communicate with the controller’s main circuitry, often a microprocessor, to hand off signals with a system-wide impact. For example, if a disarm signal is received by the security system control module, this signal is passed to the home system controller, which then first communicates with the lighting module to turn up the house lighting and then back to the music system to play jazz.

Hard-wired control systems are the most reliable type of communications links that can be used to connect a system controller to subsystems and room controls. However, they usually work on proprietary communications protocol. In addition, they are usually the most expensive of the available options.

Most hard-wired systems communicate over the Cat 5e cabling installed as a part of a structured wiring system or over a proprietary cabling system. The controller can be connected to the network cabling using two primary methods: using a network adapter that is either built into the device or available as an add-on module (see Figure 39-2) to the controller or through a connection made in the distribution panel (see Figure 39-3).

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Figure 39-2: A controller network interface add-on module

Photo courtesy of Crestron Electronics.

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Figure 39-3: An illustration of how a hard-wired home system controller connects into a home’s structured wiring

Another advantage of a hard-wired control system is that it is able to perform multiple tasks at one time. Because of the data speeds supported by unshielded twisted-pair (UTP) cabling, a hard-wired system is able to communicate at a faster data transfer speed and still maintain its reliability. Hard-wired systems are best installed during new home construction, as they are difficult to install with the necessary wiring as part of a retrofit or remodel project.

IP-Connected Controllers

A variation on the hard-wired approach to communications in a home control system is an Internet Protocol (IP) control system. IP control systems interconnect the home system controller and the room controls into the home computer network (see Figure 39-4) to create what amounts to a home intranet that is called a controller-attached network (CAN). An intranet is a network contained within a home, as opposed to an Internet, which extends way beyond a single home.

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Figure 39-4: An illustration of a home system controller connected to a home computer network.

On an IP control system, the communication protocol is Ethernet-based TCP-IP. Each device connected to the network is assigned an IP address and the network communicates with it using that address.

PLC Controllers

Perhaps the most affordable type of home control system is powerline carrier control (PLC) systems, which are more commonly known as X-10 or CEBus. PLC uses a home’s existing AC powerline to communicate.

The heart of a PLC home control system is its network control unit (see Figure 39-5), which serves to integrate and control the various PLC units and modules. A variety of PLC system controllers are available ranging from software for PC to stand-alone controllers. And PLC systems are easy to install, because the network media is already installed in the walls of a home (the electrical wiring). Here’s an overview of the advantages of PLC communications advantages, along with the disadvantages.

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Figure 39-5: A PLC network control unit

Photo courtesy of Home Automation, Inc.

The advantages of PLC communications are

  • They use existing AC powerlines for communications media.
  • Access is available to the PLC network through any AC outlet.
  • They are compatible with data transmission and control signal transmissions.
  • They are capable of transmitting audio signals (although not typically very well).
  • System can be added to and expanded over time; not necessary to install everything at the time of new construction.

However, there are some disadvantages as well:

  • PLC signals are very susceptible to interference and electric noise on a circuit from electric motors, thermostats, dimmer controls and television signals, and radio signals picked up by the wiring.
  • Electrical noise on the AC lines can lower the transmission speeds of PLC signals.
  • PLC systems do not provide a high-level of security because they transmit over insecure media.
  • Attenuation can be an issue because of line noise and interference.
  • PLC-enabled devices can be more expensive than their standard networking counterparts.
  • They are only capable of transmitting one signal at a time, which is transmitted sequentially, since the signal requires time to travel over the electrical lines.
  • No standard has been established for PLC communications.
  • Windows computer operating systems do not include drivers for PLC products.

In spite of its disadvantages, PLC can be used in certain situations fairly effectively, such as controlling light fixtures and electric devices in a single room or smaller-size home (less than 2200 square feet).

Wireless Controllers

Wireless control systems can communicate using IR, RF, or IEEE 802.11b standards. Most often, wireless control systems, room, zone, and whole house remote controls transmit command and control signals to the central home system controller through the air using radio waves.

The IEEE 802.11b standard, also known as Wireless Fidelity (Wi-Fi), is a wireless communications standard that operates in the 2.4 GHz RF band. The 802.11b offers up to 11 Mbps of bandwidth in a range of around 150 feet indoors. At the present time, 802.11b is the most commonly used wireless networking standard. Table 39-1 lists the characteristics of the wireless networking standards on the market.

Table 39-1: Home Network Wireless Communications Standards


RF Band


Indoor Range


5 GHz

54 Mbps

25 to 75 feet


2.4 GHz

11 Mbps

150 feet


2.4 GHz

54 Mbps

150 feet


2.4 GHz

720 Kbps

33 feet

The advantages of wireless networking include the elimination of cabling between a remote control device and the system controller, and the portability provided by the lack of wiring. Another advantage is that the system is fast enough to provide bandwidth to overcome most interference problems, which are highly probable.

The disadvantage of wireless networking is its operating frequency. All of the 802.11 standards, and the Bluetooth standard, operate at 2.4 GHz, the same frequency used by many cordless phones, some garage door openers, baby monitors, and other wireless products commonly found in a home. In addition, wireless digital subscriber lines (DSL), or wireless Internet access to a home, also operates on this frequency. So, the possibility for interference is real, but as mentioned earlier, the bandwidth and data speeds are high enough that in most cases, interference can be overcome, though it’s not always true in all cases.

In its best application, the use of wireless communications should be limited to transmissions between room and zone controls and the system controller only. This is for two reasons. First, there aren’t many wireless subsystem interface modules available; and secondly, the traffic stream between the system controller and the subsystem control unit needs to be reliable. In this case, wiring is the best option. In a home that has structured wiring installed, the best approach is to interconnect the home system controller into the hard-wired environment for communications between the system controller and the subsystem controls over the structured wiring (see Figure 39-6).

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Figure 39-6: A home system controller in an RF wireless network relays signals to subsystem modules and devices over the integrated wiring system.

Controller Setup

When installing a home system controller, there are some basic steps you should followed to ensure the control system meets the needs of the homeowners and the installation goes efficiently. On all systems, you should work on much of the system configuration prior to visiting the site for installation and setup. The programming needs to be done very carefully. It is much more effective to find the problems and resolve them at the workbench then out in the field. Troubleshooting on-site is inevitable, but you want to keep it to a minimum.

The steps you should use to set up and configure a home system controller are

  1. Interview the homeownersTo be sure that the controller will best serve the needs of the homeowners, you should discuss the lifestyles and desires of the homeowners to help define the setup of the system. Also discuss system options and capabilities in detail to gain an understanding of the homeowners’ expectations of how the system will perform once it is in place.
  2. Set Up control devices and programsHere is where you layout the devices to be controlled and the desired programming. Be sure to follow the basic configuration of the controller according to the manufacturer’s specifications and guidelines. Documentation is critical at this point because you will probably need to refer to it in the field. Remember, it is much easier to pre-program the controller in advance and off-site and then just install it on-site and upload the programming as necessary.
  3. Program macros and scenesDuring this step of the process, you should program and document any scenes or macros into the controller for testing on- site. Some systems include interactive macro creation software, but for most, the process involves opening a new macro and recording the keypad buttons using a logical order of operations, as if the user were pressing the buttons to request the sequence of actions included in the macro. Again, follow the programming documentation supplied by the manufacturer.
  4. Design and create user interfacesMost home system controls and many touch screen and keypad controls allow you to customize the placement and the function of hard keys and soft keys to meet the needs and wishes of the users. Using the information gained during your interview with the homeowners, design and set up the user interfaces on the control devices to meet the homeowners’ requirements. Again, remember that documentation is critical. It is often beneficial to share the physical layout of the buttons on keypads and touch screens (an actual drawing of the control device with buttons labeled) with the homeowner prior to programming them, as they may have changes they would like and it is easy to make them initially.
  5. Install controllerNow is the time to visit the site and physically install the controller unit or the control software on a local PC. Load the setup and programming you’ve done previously, and you’re ready for the next step.
  6. Connect communications links and test local controlsYou should now connect and test the communications links with the control functions for both the local controls and the system controller, at least at a basic operational level. For example, does the request to dim the lights in a room result in the lights actually being dimmed? The settings may not be exactly right at this time, but the objective is to ensure the controller and the local controls are able to communicate and function together. Also check that any status messages that should be returned to a local control with a user interface display are displaying properly. You should test all controls thoroughly and correct any problems you encounter before proceeding to the next step.
  7. Acceptance testing When the system is completely set up and configured properly, perform a complete test of the system to ensure none of the homeowners’ requirements have been overlooked or aren’t working properly. Once you are satisfied that the system is working as specified, assist the homeowners in a complete run-through of all of the system’s functions and actions. If the homeowner requests adjustments or changes, make the modifications and perform this step again completely.
  8. System maintenanceChances are that the homeowner will want some changes to the system or the user interfaces within the first 30 days of the system’s operation. In anticipation of this, you should make some arrangement, with an appropriate fee schedule, with the homeowner for a warranty, system changes, and ongoing system support.

On many systems, modifications can be made without the need for a house call, or what the communications people call a “truck roll.” On systems that provide remote access, most problems or minor changes can be done by accessing the system through a modem or over the Internet and gaining access via a security code (which should be kept top secret at all times). A house call should be necessary only for major reconfigurations of the system or hardware problems, and if the system has been properly installed to the homeowner’s wishes, it shouldn’t be a common occurrence.


A home system controller consolidates the functions of the separate subsystem controllers into a single user interface for the homeowner. Home system controllers can be hardware-based or software-based.

Hardware-based controllers are specialized devices with a microprocessor for processing inputs and control. They are equipped with relays, input and output jacks, a variety of optional communication ports, and have embedded processors to provide stand-alone functionality for the home control system. Many home automation control software products work with Ethernet networking, regardless of the media in use, although some are specific to certain media.

Home system controllers can be connected directly or can use communications media to transmit signals to the devices controlled. Four methods used to connect a controller to the devices or subsystems it controls are: hard-wired, IP-connected, PLC, and wireless. Home system controllers use either one-way or two-way communications.

Hard-wired control systems are the most reliable of the communications links that can be used to connect a system controller to subsystems and room controls. However, they usually operate on proprietary communications protocol and are usually the most expensive of the available options. IP control systems interconnect the home system controller and the room controls into the home computer network. On an IP control system, each device connected to the network is assigned an IP address and is communicated to across the network with that address. The most affordable home control system is PLC, which uses a home’s existing AC powerline to communicate. Wireless control systems communicate using IR, RF, or IEEE 802.11b standards.

When installing a home system controller, some basic steps should be followed to ensure the control system meets the needs of the homeowners and the installation goes efficiently. The steps that should be used to set up and configure a home system controller are: interview the homeowners, set up control devices and programs, program macros and scenes, design and create user interfaces, install the controller, connect communications links and test local controls, perform acceptance testing, and provide system maintenance.


  1. Which of the following best describes the basic function of a home automation system controller?

    1. Centralized maintenance
    2. Centralized interface
    3. Consolidation of separate subsystem controller functions into a single user interface
    4. Remote access for system maintenance
  2. Of the following, which is not a commonly used communications technology or protocol for home automation control systems?

    1. Hard-wired
    2. IP-connected
    3. PLC
    4. HomePNA
  3. Of the media configurations common to home control systems, which is considered to be the most reliable?

    1. Hard-wired
    2. IP-connected
    3. PLC
    4. HomePNA
  4. On what cable media are hard-wired home control systems typically installed?

    1. AC powerlines
    2. Coaxial cable
    3. UTP cable
    4. 2-conductor 22 AWG wiring
  5. What technology does the popular home automation protocol X-10 operate on?

    1. Ethernet
    2. IEEE 802.11b
    3. PLC
    4. Wi-Fi
  6. What is the indoor range of an 802.11b network access point?

    1. 25 to 75 feet
    2. 50 to 100 feet
    3. 300 to 500 feet
    4. 330 meters
  7. What is the primary disadvantage of using IEEE 802.11 networking?

    1. Interference with other 2.4 GHz devices
    2. Limited system controller offerings
    3. Line-of-sight
    4. Operating range
  8. Which of the following is not typically a feature of a hardware-based home system controller?

    1. Communications with standard protocols
    2. Local access only for security reasons
    3. Macros
    4. Multiple-zone control
  9. What should be the first step performed when preparing to install a home systems controller?

    1. Perform acceptance testing
    2. Install controller
    3. Interview homeowners
    4. Connect communications links and test local controls
  10. A command sequence of several actions that can be enacted through a single button is called a(n)

    1. Automated local control
    2. Macro
    3. System interface
    4. Program


  1. C. The other choices listed are features of a home system controller, but the home automation controller’s primary purpose is to consolidate the control of the subsystems.
  2. D. HomePNA is primarily used for data networking, although some advancements are being made to apply this technology to home control systems.
  3. A. Hard-wired systems are the least susceptible to interference.
  4. C. UTP cable is installed as part of a home’s structured wiring system.
  5. C. Powerline control (PLC) protocols include X-10 and CEBus.
  6. A. The range of this technology depends on the construction of the home and its furnishings.
  7. A. None of the other choices are factors with 802.11 wireless communications.
  8. A and B. Although local access for security may sound right, most of the better home control systems offer remote access that is gained only after a security code is entered and nearly all systems are compatible to standard communications standards.
  9. C. It’s hard to know exactly what the homeowners’ vision or expectations are for the control system without first discussing their lifestyles, the system, and its functions in detail with them.
  10. B. Also called a mode or a scene, macros group a sequence of commands together so they can be executed as a single command stream.

Part I - Home Technology Installation Basics

Part II - Structured Wiring

Part III - Home Computer Networks

Part IV - Audio/Video Systems

Part V. Home Lighting Management Systems

Part VI - Telecommunications

Part VII - HVAC and Water Management

Part VIII - Security System Basics

Part IX - Home Technology Integration

Part X - Appendices

HTI+ Home Technology Integrator & CEDIA Installer I All-In-One Exam Guide
HTI+ Home Technology Integrator & CEDIA Installer I All-In-One Exam Guide
ISBN: 72231327
Year: 2003
Pages: 300

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