It's all about automation and controls, but what other capability?Okay, let's say that you have responsibility for this great 3-story building... It has the three to five of the best air handlers, various supply and exhaust fans, maybe a fan-coil or two, a central plant with a hot water boiler and chilled water system. All of the thermostats have a digital setpoint and temperature display and they individually connect to 38 Variable Air Volume (VAV) air terminal system throughout the building. You expect this automated system to work together, as efficient as possible, with little operator involvement (except for minor maintenance and adjustments), right? .... Of course. The system mentioned above is fairly typical of a small administrative-type of building. What about the other systems not mentioned in the example above? Did you know that your automation system is expandable? That it can integrate to other vendors (like a Fire Alarm panel, Engine Generator, Power Conditioning System, etc)? Has an array of communication abilities that range from being proprietary, to BACNet/IP, to Ethernet, RS485/422/232 two and four wire systems, to LONWorks? Let's take a look at how the building above might tie together... First, a few definitions will help. 1. ASC Device: The term ASC stands for "Application Specific Controller." These controllers are often made for a specific purpose (as the name implies), but, can also be programmed as a "Point Multiplexer." For example, a Control System company might offer an ASC called a "Unitary Controller." (UNT) The UNT was made for applications such as: A fan-coil, an air handler, or even a smaller packaged chiller. The controls company makes software for the UNT that has "pre-configured" applications that you can modify, just select the appropriate one. A Point Multiplexer program lets the UNT also act like a "blank sheet of paper." You can specify all or only some of the hardware points for a basic control scheme. This might be a good way to go if you are able to software interlock exhaust fan points, for example, and do not want to spend the dollars on a larger, more feature packed-controller. There are many common ASC's that are made to specifically control air handling units (AHU's), VAV's, and of course, the multi-purpose UNT. 2. Point Multiplexer: A configuration that allows an ASC controller to become an "Input/Output" device. There may be no control routines involved, or if there are, they may be very basic (Example: termination of four exhaust fans for run command and status). 3. Software Interlock: What if you have an air handler ASC and need to tie-in an exhaust fan to run with it, but are out of physical hardware points? You can add a UNT near the exhaust fan, and tie the UNT into the communication trunk. Using software interlocks, the UNT can be programmed to start the exhaust fan (via network) with the air handler. 4. Physical Hardware Point:An electrical termination to the ASC controller, where the opposite end is terminated at a "device." 5. Device:This is usually the end item, you might also find this called a "controlled device," as in the case of a variable speed motor. This can be a temperature sensor input, a relay (to command a fan to start), a fan status monitor, or could be an output to a valve or damper. 6. Communication Trunk. Most Building Automation Systems have two communication trunks: - One for the system itself, originating from a "supervisory device" that connects all or a portion of the ASC's and controllers within a building, and - One that connects the system above to a Local Area Network trunk, such as the Ethernet, connecting the Operator Workstations and other "supervisory devices" on a common trunk. Alright, now let's look at some capabilities: Realize that all of the functions below can be done from a desktop computer, (known as an Operator Workstation) if your system has the required software. In addition, either a communication trunk connection, or an interface called an "integrator" will be required to make the panels below work with your building automation system. 1. Fire Alarm Panel Integration. Along with other useful features, every device on your Fire Alarm panel can be shown graphically, allowing maintenance people to quickly find a trouble device, or pinpoint an originating alarm. 2. Security System Integration.Access card management, tracking, and scheduling your building access can be done. 3. Direct access to a "3rd Party Vendor" such as: - Your chiller. - Your Boiler. - Your Engine Generator. - A Power Conditioning System. - Your Switchgear. - Energy Management devices such as a BTU Monitoring system. - A Lighting Controller. - a Specialized air handler, such as a Liebert. (Direct Access means that your building automation system "sees" every point within a particular vendor's panel, as if you are standing at the panel, pressing buttons and reading the panel/machine's local display) There are so many systems that can integrate to your Building Automation System today, the possibilities are almost endless. 4. Energy Savings.Custom software routines, that are made for reduction in utility costs, such as: - Demand Limiting or Load Rolling, Where specific equipment can be shut-down for brief periods, or specific circumstances (like a peak electrical period). - Optimal Start/Stop, used to efficiently start an air handler (for example) based on specific and adaptive building conditions. - Central Plant optimization, where the chiller and boiler setpoints can be reset based on several Outdoor Air factors (dry/wet bulb, enthalpy, building load, etc). 5. Home Automation.This discussion centers around the commercial building scenario, but there are many home automation systems for your personal residence that work in a similar way.
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