BUILDING MANAGEMENT SYSTEMS II: Core Concepts

26c.- Sometimes comfort is affected by things other than set points

- Do the diffusers provide good air mixing? Sometimes they are directly above an occupant who will feel cold from the air dropping on them even though the ambient temperature is at set point. - Are there different pieces of equipment trying to condition a shared space? Make sure they aren't fighting against each other - Is the sensor in a location that provides accurate readings? Avoid exterior walls and direct sunlight. Sometimes air inside the walls is very different from the room temperature. If there are large openings behind the sensors, you may need to fill them. - Make sure there are not pieces of office equipment affecting the room temperature sensors. Copying machines and personal heaters are notorious for locking systems into cooling when it isn't needed.

26d.- Sometimes comfort is affected by things other than set points

- There may be a difference between the temperature an occupant thinks the set points should be, and where they are actually comfortable. A request for warmer or colder maybe more effective than a visible set point. - Avoid adjusting set points more than a few times per day. It takes time for temperature sand systems to stabilize after changes - Use trend logs to verify how the system responds and what the impacts on energy usage and comfort were. Buildings can be unpredictable and trend logs are essential for running a building optimally

13b.- Two methods for the BMS to interact with equipment in a building

1.- The first method is that factory-packaged equipment like rooftop units, variable frequency drives, chillers, heat pumps, etc. may include the capability to communicate using an open protocol like BACnet or MODBUS. If so, the BMS can communicate directly with the circuit board inside the packaged equipment. This is the most efficient method in terms of the cost of installation, and in terms of the amount of information that can be exchanged

13c.- Second method for the BMS to interact with equipment in a building

2.- The second method is that the BMS can monitor and control equipment by running wires between a BMS controller and the equipment. The BMS can monitor and control equipment by running wires between a BMS controller and the equipment. A pair of wires that brings a single piece of information into the controller is referred to as an Input point, and terminates on an Input terminal of the controller. Similarly, a pair of wires that runs from an output terminal on the controller to send a command to equipment is referred to as an Output point. Input points and output points are both said to be hard wired, and referred to as hard points, because each individual point needs to be separately wired. Each hard point has an Input or Output device on one end of a wire, and controller terminals on the other end

10a.- Hardware

A BMS is composed of hardware and software components. Hardware includes anything physical, like controllers, sensors, actuators, transformers, and networks. Some hardware devices have some microprocessor on board containing the operating system that operates the hardware device

14a.- BMS Controllers BMS's such as distributed DDC systems require several controllers

A controller is a dedicated computer designed to operate only on specific program. HVAC controllers receive information from sensors and sends signals to actuators. They are often located in the mechanical equipment room. When connected by a communications network, the controllers provide comprehensive control and monitoring of the HVAC equipment in a building. Controllers are often referred to as control modules, modules, and panels. Controllers include application-specific controllers, universal input-output controllers and network communication modules

16a.- Network Communication Module (NCM)

A controller that coordinates communication between controllers in a network and provides locations for operator interface. Typically, BMSs do not allow individual controllers to communicate directly with each other. In most applications, an NCM collects information from individual controllers and distributes it to other controllers in the network. One NCM is typically required in small-to medium-size buildings that have up to 200 controllers

10b.- Direct Digital Control Systems

A direct digital control (DDC) system is a control system in which electrical signals are used to measure control system parameters from multiple microprocessor-based controllers

16e.- Server Data

A server computer is a computer attached to a network with a large storage capacity for electronic files and data

14c.- Unitary Controllers

A unitary controller is a controller designed for basic zone control using a standard wall-mount temperature sensor. Unitary controllers are designed to control packaged HVAC equipment such as rooftop units, heat pumps, and fan coil units. Unitary controllers are typically compact to allow mounting at the packaged HVAC equipment. Weather tight and heated enclosures are often used, which allow operation of multiple stages of heating and cooling, economizer dampers, heat pump reversing valves, and supply fans. Some unitary controllers provide supply-air sensing capabilities, switches and/or sensors to determine airflow, and dirty-filter-condition switches (differential pressure switches)

15e.- Universal Input-Output controllers

A universal input-output controller is a general controller designed to control most HVAC equipment. Many UIOCs have the same two-piece constriction as ASCs. UIOCs have a fixed number of inputs and outputs, with 8 and 16 being the most common. Most UIOC's use 24 VAC power supply

15b.- Variable-Air-Volume Box Controller

A variable-air-volume box controller is a controller that modulates the damper inside a VAV terminal box to maintain a specific building space temperature. VAV box controllers are similar in appearance to unitary controllers. The difference is in the manufacturer programming of the EPROM (erasable programmable read-only memory)chip

31b.- Pop-Up notifications

After programming changes have been made to a system, it may occur that there are alarms on the current alarms worksheet that cannot be acknowledged. To clear one of these alarms, click on the alarm and select CLEAR

29e.- Pop-Up notifications

Alarms can also be configured to generate pop-up notifications. Pop-ups include the alarm type, priority, text, Source and Time of the alarm

29b.- Removing Alarms

Alarms will be removed based on their configuration. Typically this is once they have been acknowledged and the alarm condition has reset. The default columns of the worksheet display the time the alarm occurred, the alarm type, the alarm text, its current state (indicating Alarm, Acknowledged, or Reset), as well as the source. BACnet alarms will display the device name with the device instance number in parentheses

14d.- Air-Handling Unit Controllers

An air handling unit (AHU) controller is a controller that contains input and output signals required to operate large central-station AHUs. AHU controllers control humidity levels, static pressure and indoor air quality. Many central-station AHUs have complex control sequences. Dual-duct and multizone AHUs have needs that cannot be met by a unitary controller. AHU controllers are larger and more complex than unitary controllers. Also, AHU controller software is more complex than unitary controller software to allow the handling of the complex control sequence

14b.- Application-Specific Controllers

An application-specific controller (ASC) is a controller designed to control only one type of application. ASCs are typically used to control HVAC systems. ASCs are more cost-effective than other types of controllers because most of the software programming is done by the supplier. Typical ASCs include unitary, air handling unit, and variable-air-volume box controllers.

16b.- There are many methods by which individuals can use and access information from a BMS such as the use of an operator interface

An operator interface is a device that allows individuals to access and respond to BMS information. Operator interface methods include the use of on-site and off-site devices and retained server data. Proper performance of the system depends on correctly using the appropriate operator interface device.

17e.- It is very important to understand the difference between

Analog and binary input devices as they supply different information and are handled differently in the controller database. IF the question is "what is the room temperature?" a binary device might indicate normal or high, while an analogue device might indicate 22.3 degrees C. If the input device is a switch, a limit, or stat, it is probably a binary device. If the device is a transducer, a sensor, or a transmitter, it is probably an analog device

4a.- Building Management Systems (also known as Building Automation System (BAS) & Building Management and Control System (BMCS)

Are intelligent microprocessor-based controller networks installed to monitor and control a building's technical systems and services such as heating, ventilation, lighting, hydraulics. BMS links the functionality of individual pieces of building equipment so that they operate as one complete integrated system

11c.- The third tier is

At the unit control system. These are a series of terminal controllers. Each control panel is programmed to control one major piece of equipment such as a VAV terminal, chiller, cooling tower, or boiler

8a.- With respect to Control manufacturers in particular

BACnet allows owners to mix control devices from different manufacturers in a single building, or multi-building network using a single protocol, communication network, and operator interface to communicate with all components

7c.- BACnet is an open protocol, manufacturers can incorporate it in their products without paying any royalties.

BACnet enables interoperability between microprocessors embedded in building equipment including HVAC controls, boilers, chillers, air handling units, variable frequency drives, lighting systems, security systems, elevators, etc. The term interoperability has a variety of meanings, from simple information exchange to allowing on device to send a command to another manufacturer's device to starta chiller or even reboot the device. For example, the old method of controlling a VFD was to run pairs ofwires between controller and VFD for every single stop/ start, speed, or status function.

6d.- BACnet

BACnet is a data communication protocol for Building Automation and Control Networks. BACnet is both and international (International Organization or Standardization) and American (American National Standards Institute) standard for interoperability between building automation devices. The BACnet standard was created and continues to be maintained by ASHRAE (the American Society of Heating, Refrigeration, and Air-Conditioning Engineers). ASHRAE publishes over 4000 standards for the design and maintenance of indoor environment

10c.- Central DDC system

BMS system that used centrally located microprocessor-based controller to make operating decisions. This is architecture is not very fault tolerant because when the computer stops working or communication wiring is interrupted, any automatic functions immediately halted

4b.- The concept of installing thermostats in buildings was introduced in the 1800s

Before that buildings were operated manually. Operators in those days had to startup the boiler, turn on the lights, and open windows manually to keep occupants comfortable and minimizing energy costs. The mechanical, electronic, and pneumatic control systems common in the 1900s were definitely' automatic control systems', but it was really the introduction of the computer that allowed centralization of building automatic control systems into a single Building Automation System

5a.- As computers became smaller and more reliable

Building Automation Systems became more 'distributed', with small computers or controllers spread throughout the building, wherever there was something to control or measure. Nowadays, the best practice is to locate the intelligence physically at the equipment being controlled. With that strategy, a single communication or computer failure has much less effect on the BMS. Each controller has its own programmed sequence of operation, and can operate in a 'Stand-alone' mode until central communications are restored

6c.- Nowadays every mechanical and electrical component in a building comes with a microprocessor on board:

Building owners make as many as possible of these components to be connected to the BMS. The problem is that the components are manufactured by different companies with different processors, running different operating systems. To be able to integrate all of these components, we need them all to use a common language, or protocol for communication. Various protocols have been used in the past 3 decades, however the most common protocol used in Building Automation Systems around the world is BACnet

5c.- Benefits

Buildings are very expensive to construct and operate, but the people living and working in the buildings are even more important. Even a modest increase in the ventilation rates of a building can have a huge impact on the health and cognitive function of the occupants. So, a good Building Automation System can save money by: improving the health and cognitive function of workers, providing security and life safety, extending the life, and reducing the maintenance cost of building structure and equipment, and minimizing the energy and water consumption of the building

29c.- Removing Alarms

By default the alarms on the current alarms worksheet are sorted by the date and time they were received, however you can sort the list of alarms by any of the columns by simply clicking on the column header. This can be particularly helpful for finding important alarms on a crowded current alarms worksheet

32b.- Accessing a Calendar Worksheet

Calendars can be accessed from a link on System Group graphic or from the calendar worksheet. From a system group the link could be a calendar icon or could be a buttonlike this

32a.- Calendar & Scheduling

Calendars provide a multi-year, 365 day calendar on which you can mark days for Holidays or recurring events. They are a binary object which normally has a value of off. IF the current day is marked on the calendar, then the calendar with have a value of ON. Calendars are almost always paired with a BACnet Schedule using a special event. With this configuration, any day that is tagged on the calendar will cause the paired special event to occur. Calendars are perfect for events that require the same hours of operation. For example, holidays when the building is closed, or dances that always happen from 7pm until 10pm

19b.- OUTPUTS Digital (binary - on or off)

Command (on/off, open/close)

12a.- Controllers in network

Commonly share information using communication protocols. A controller that needs information from a failed controller in the network is unable to access that information. In that case, the controller continues to function at a reduced level or efficiency

21b.- The Menu

Contains a title for all non-group pages as well as functions native to the MACH-ProWeb™ interface. The menu will change based on user permissions and the contents displayed in the Work area. The banner in the user interface picture above has the following click down options: Scaled, More, Help, and Log Off

10d.- Distributed DDC system

Control system in which operating decisions are made by local microprocessor-based controllers with the decision-making ability distributed throughout the controlled system. Distributed DDC systems typically have a supervisory or master controller. Distributed DDC systems are the BMS systems typically used today and replace central DDC systems. With this system, a single communication of computer failure has much less effect on the BMS compared to a central DDC system. Each controller has its own programmed sequence of operation, and can operate in a 'standalone' mode until central communications are restored. The workstations we use n this class are distributed DDC system

18c.- Analog output

Devices (sometimes referred to as modulating), have an infinite number of values between the limits of the range of the device, and analog units like percent and VDC: 0-100%, 0-12 VDC, Typical analog output devices include a Modulating actuator, a variable frequency drive, or a 0-10 VDC reset signal packaged device.

18b.- Binary Output

Devices (sometimes: stop/start referred to as two-position) have two possible states, for example: stop/start, close/open, or disable/enable. Typical binary output includes a Relay or Contactor, two-position actuator, or a dry contact

12b.- DDC System Functions

Distributed DDC systems have the same control function as central DDC systems which include duty cycling, electric demand control, and time clock functions. Distributed DDC systems also can perform precise closed loop temperature control, humidity control, and pressure control operations

19a.- OUPUTS Analog (varying - positioning)

Fan speed regulating (0 to 100%), chilled water valve control (0 to 100%)

13d.- BMS controllers

Have a fixed number of hard input and output terminals. If you double the number of hard points on a project, you double the number of devices, the amount of wire, the number of controllers, the number of control panels, the number of transformers, etc. For this reason, the cost to install a control project is closely linked to the number of hardwired points on the project. Controllers also have soft points contained in their database, used for Direct Digital Control, scheduling, historical data storage, programs, and to facilitate the operator interface. Soft points are easy to create, and so are not tied so closely to the project cost

17d.- Analog inputs

Have an infinite number of values between the limits of the range of the device. For example, 0-100%,-30-45 degrees F, etc. Typical analog input devices include: A temperature sensor, a current transducer, tank level transducer, or a flow transducer

12c.- Distributed DDC systems

Have improved reliability and increased capacity over central DDC systems. Because the controllers in the distributed DDC system can stand alone, distributed DDC systems are modular and easily expandable. A BMS can be started with a minimum number of controllers and expanded as required

17c.- Binary Inputs

Have two possible states: off/on, closed/open, normal/alarm, etc. Typical binary input devices include: a differential pressure switch, a manual switch, a freeze thermostat, or a current switch

17b.- BMS Inputs

Input points are like the answers to questions asked by a controller. For example, tor drawing? Is the damper open? All of these questions can be answered by input points. Inputs can give you information about the temperature, the humidity of a room, flow rate of chilled water, pressure, level of a tank, run statuses of pumps and fans, among other data

6a.- In BMS terms

Integration means connecting together the various building systems so that information can flow between them and the operator

11e.- Global data

Is data that is needed by all controllers in a network. Global data includes outside air temperature and electrical demand

11f.- Stand-alone control

Is the ability of a microprocessor-based controller to function on its own. Stand-alone control is less risky because a controller failure is local and has minimal effect on the entire system. Stand-alone control enables system to function without the operation of a failed controller, which increases the reliability of the BMS

22b.- Work area

Is the rest of the space that can change depending on what is being focused on. The work area occupies the majority of the user interface and is used for displaying system group graphics, current alarms, calendars, schedules, runtime logs, and trend logs

21a.- The Banner

Is the uppermost section of the user interface. The banner will look different depending on what system is used in the building

8d.- When implementing BACnet in a building

It is essential that all BACnet devices are BTL listed, ensuring that they will be able to communicate together and deliver the full benefits of BACnet

8b.- BACnet Protocol

Knowledge of the protocol is necessary for manufacturers, and also for consultants and contractors tasked with making BACnet operational on jobsites. The BACnet protocol can be implemented with a growing number of physical networking standards, including: Ethernet, wireless Ethernet, among other standards

22a.- The Navigation tree

Lists all of the different floors and the different devices that are appear on each floor

16c.- On-site operator interface method

Maintenance or management personal personnel of medium and large buildings, such as hospitals, colleges, and office buildings, commonly access and trouble shoot BMS as part of their normal work responsibilities. On-site devices used to access and trouble shoot BMSs include desktop PCs, alarm printers, notebook PCs, portable operator terminals keypad displays, and dumb terminals

15c.- VAV box controllers modulate

Modulate the primary damper inside the VAV terminal box. Reheat valves can also be controlled. A flow input to the controller can be set up to indicate airflow (in cfm). The controller turns the fans in the VAV box on and off based on the input. The software of many VAV box controllers allows VAV terminal boxes to be checked for proper air balancing (proper cfm of air)

26b.- Adjusting set points is

Often more complicated than the simple task of changing the value. Occupants often have conflicting requests. Sometimes the changed don't result in what you expected. It takes time, experience, and experimentation to become an expert at your building and its set points. Only adjust set points that you are familiar with and know what they do

32d.- Accessing a Calendar Worksheet

On the worksheet you can see all the calendars in the controller listed by name

16d.- Off-site operator interface methods

Operators and technicians may need to access HVAC systems from outside of the building. For instance, an operator or a technician might need access during the weekend from home. There are many methods that are used for off-site operator interface to view system control functions, but these days the most common way to get access off-site is via a browser using an Internet connection. Text messages and email alarm function are also available and are sent to system operators. There is more and more use of browser-based tablets and smartphone to receive updates

4c.- Building Management Systems were all about Heating, Ventilation, and Air Conditioning (HVAC)

Other important automatic systems were soon added. Imagine the benefits of having a single computer that can communicate to these systems: HVAC, lighting, security, fire alarm, irrigation, domestic water, and elevators. Buildings that incorporate multiple systems into a single BMS are said to be 'Intelligent Buildings' and the multiple systems are "Integrated" so that information can flow between them. ABMS is centralized, meaning that multiple systems can be accessed from a single software interface

18a.- Outputs

Outputs are like commands being issued by the controller. For example, 'start the fan! '"Open damper 50%', etc. There are two main classes of devices that can be wired to outputs: Binary and Analog. Outputs include valves, VFD speed command, air dampers actuators, on-off command for fans, pumps and boilers, among others

8c.- The BACnet protocol uses an object-oriented model for representing information

Over 54 standard objects are available, plus manufacturers can create their own objects for specific applications while still using the BACnet protocol for communication to other devices that choose to use it. To ensure consistent implementation of the BACnet protocol by manufacturers, ASHRAE created a global, independent third-party testing and listing program. The BACnet Testing Laboratories, or BTL, is managed by BACnet International, and awards the 'BTL Mark' to devices that are tested according to ASHRAE standard 135.1, the companion test standard to BACnet

15f.- ASCs are manufacturer

Programmed and can control only the equipment for which they are designed. UIOCs are used to control most HVAC equipment. UIOC programming is blank when shipped from the manufacturer and mist be custom programmed in the field. Usually, the manufacturer provides software tools and interface cables. UIOC programming requires a high level of familiarity with the manufacturer's software

11d.- The supervisory controller of a distributed DDC system

Provides communication support, a convenient connection to a personal computer or Internet network for monitoring purposes, and connections for global data.

21c.- The Menu contains

Scaled: The scaled drop-down list is used to set the System Group scaling mode to accommodate different monitor sizes and user preferences. Help: The help button opens a drop down men with three items: - Show Tooltips toggles the tooltips - User Guides opens the context sensitive User Guide - About Mach-ProWeb opens a window with more information.• More: The More drop-down menu has six items. - Print: opens a Windows print dialog box and allows for printing either the trend log chart of data. - Export: The export button allows users to save the current trend log in CSV format. This allows for easy importing into a spreadsheet. - Audit Trail - Alarms - Theme - Set System Time Log Off: The Log Off button logs the current user off and returns to the Logon screen

25a.- Adjusting Set Points

Set points are one of the primary ways operators interact with their BMS. They could be something simple like a room temperature set point, or something that requires an understanding on how the equipment works, like a refrigerant pressure set point. Set points are often found in system groups often identified by the information found under a device (like the one pictured below),an icon with SP, or a slider on them and also on the values worksheet

31a.- Pop-Up notifications

Some actions will occur automatically, while other prompt the user to execute the Actions on the alarm Pop-up

18f.- INPUTS Digital (binary - on or off)

Status (on/off, airflow, run, open/close), alarm

18e.- INPUTS Analog (Varying-reading)

Temperature, humidity, water flow, airflows, tank level, energy, KW, voltage, current, pressure pH, conductivity

4d.- Originally, that also meant that everything was controlled by one, or very few computers.

That architecture was not very 'fault tolerant', because when the computer stopped working, or communication wiring was interrupted, any automatic functions immediately halted

28b.- Accessing Current Alarms

The CURRENT ALARM worksheet is the primary way to view and manage alarms in the system we are working on in class. It shows all alarms broadcast to their internetwork. You can access the CURRENTALARM worksheet in a number of ways by clicking the Alarms icon

10e.- DDC System Architecture

The DDC system architecture is going to depend on the size of a building. In a smaller building computerized HVAC controller operates the DDC system. Larger buildings would normally require a complex system of controllers divided in tiers. This is what we call system architecture

28d.-Each alarm is shown as a row on the worksheet

The color of the row and text are a visual indication of the current status of the alarm. First let's defined a couple of terms:

15a.- A typical AHU controller application

The control of a variable-air-volume unit to maintain a minimum static pressure in the supply duct. In this application, heating and cooling control is performed to maintain a constant discharge air temperature of 55°F. An output (static pressure sensor) from the AHU controllers is provided to increase the volume of air provided by the supply fan. The air volume increase is produced by controlling the speed of the fan mother using a variable frequency drive (VFD) or by opening dampers on the fan to admit a greater amount of airflow

7a.- Although work started on the standard in 1987

The first version of ASHRAE's BACnet standard 135 was published in 1995. Since then, the standard has been continuously developed, incorporating new technologies and communication methods. Currently, the BACnet standard is at version 14. The development process uses an open consensus process where any and all interested parties are welcome ,and may participate without fees. ASHRAE ensures that the BACnet community is composed of members representing manufacturers, owners consulting engineers, academia, government and general interest

6b.- There are many benefits of BMS, here are just a few:

The operator just has to learn one software interface, instead of having different interfaces and maybe even different computers to learn and maintain. Presenting a security card to open a door in the morning could turn on the HVAC and lighting in a specific office. A signal from the fire alarm system could be used by the HVAC system to turn fans and dampers off and on, thereby minimizing smoke circulation while occupants exit the building. The BMS could access time updates from the Internet, and keep all systems synchronized to the correct time. The BMS could send automatic emails upon critical failure of any system. The security system could notify the lighting system to flash all the lights while break-in was underway

9.- The BACnet protocol has already survived for more than 22 years, but what guarantee do building owners have that it will continue to be supported and developed into the future

The protocol is designed to be 'extensible', meaning that as new communication methods and new applications arise, the standard can be added to and expanded-allowing it to be compatible with new technology. The standard can only be added to, not taken away from, so owners who invested in BACnet devices many years ago cannot be cut off. Devices compatible with new versions of the BACnet standard will still be able to communicate with devices that only support old versions of the protocol. So BACnet really allows owners to 'future-proof' their buildings by allowing backward and forward compatibility

7d.- With a single BACnet connection

The same VFD could allow the controller to access perhaps 75 data objects, including the above functions, plus kW, kWh, Amps per phase, temperature, run status, etc

5b.- One of the trickier functions of Building Automation is controlling devices like valves, dampers, motors and lights to maintain a measured quantity, or value, at a specific set point

The set point could be a desired temperature, or light level, or flow, or practically anything. In the early days of Building Automation, this control was accomplished using the old pneumatic and electronic components. The BMS was only used to change device set points. Eventually, computers took over the control functions themselves with inputs to measure current conditions, programmed algorithms to calculate required actions, and outputs to command-controlled devices. That meets the definition of a controller, and when a computer does it, we call it Direct Digital Control, or DDC

20a.- User Interface

The software portion of a BMS consists of applications or programs that run on computers and communicate to the BMS hardware and with each other. These applications also provide interfaces that allow operators to interact with the BMS

20c.- User Interface look like

The user interface is divided into 4 parts: The banner, menu, navigation tree, and work area.

11b.- The second tier is at the building control level.

This is a system Controller

11a.- The first tier is at the Operator-machine interface or User Interface Level

This is the central workstation which usually consists of a desktop computer or laptop. This central workstation communicates with the controllers on the second and third tiers. The central workstation can receive, process, store, send, and print data. Some things that an operator can do are: check the status of each component and the status of the system, see trends that indicate potential system problems, such as a gradually increasing difference between a space temperature and the setpoint, change settings such as set points and times of operation, among others.

28c.- Parts of the Alarm Worksheet

This is what the alarm worksheet looks like

20b.- Logging On

To access the MACH-ProWeb™ interface, open a supported browser and enter into the address bar the correct URL or IP address and port number. When a successful connection is made to the MACH-ProWeb™ interface, a logon dialog box will appear, unless public access has been enabled. If no logon dialog appears, users may proceed to view the interface as a public user with limited privileges, or, if the Log on button appears in the main menu. To log on, verify that the system name is correct, enter the appropriate User name and Password, and then click the Log on button. The User name and Password are case sensitive

25b.- Adjust a Set Point on a System Group

To adjust a set point on a System Group, click on it and enter a new value in Auto mode and click OK Some set points are commanded by programming, which may limit the range of the set point or automatically calculate it based on other conditions. If you adjust a set point and it automatically changes to another value, avoid placing it in manual override unless you have a good understanding of the sequence of operation and the potential results of putting the set point in manual override. If you need to put a set point into manual override, then timed is the best option, so it will return to normal operation automatically

26a.- Adjust a Set Point on a System Group

To do a timed override of a set point, click on the value of the system group, enter the desired value, and click in the Auto/Manual field until Timed is displayed. A Timed field will appear. Enter a time in hours and minutes, and click OK

32c.- Accessing a Calendar Worksheet

To get to the Calendar Worksheet, click on the controller in the system tree and then calendar

28a.- Alarm Management

To maximize the effectiveness of alarms, it is necessary to consider what condition you would like to be notified of. Work with a BMS technician to define important alarm conditions and remove nuisance alarms. Depending on your user level you may be restricted form some of the functionality described in this manual

19c.- Analog control

Typically more expensive, and provides more accurate control. Controller databases are created by Reliable controls Authorized dealers, or certified operators, and are customized for the equipment, and the specific sequence of operation desired. Databases are essentially a collection of points required to meet the sequence of operation. In BACnet terms, the points are referred to as objects

18d.- Floating actuator

Uses two binary outputs to position an actuator in an analog manner. It is very important to understand the differences between analog and binary output devices as it greatly impact show equipment is controlled and in particular occupant comfort level

15d.- VAV box controllers are also used in pressure independent

VAV terminal boxes with reheat applications. VAV box controllers are used to control building space temperatures and measure and control the amount of air flow. In addition to controlling building space temperature, a flow sensor is installed at the inlet of the VAV terminal box. The flow sensor (differential pressure sensor) is wired to the VAV box controller to measure airflow. Information on airflow is use by the controller to position the VAV damper. An output connection from the controller is provided to open the reheat coil valve on a call for heat

23a.- Fan Coil Unit

What mechanical equipment, coupled with a central air-conditioning system, is used to to dehumidify and cool the air stream injected to a conditioned space. Red = Very hot Yellow = Hot Blue = Very cold Green = Adequate temperature Gray = Unoccupied

7b.- The need for an open protocol for building systems arose in the early 1980s

When microprocessors started to appear in building controls and other mechanical and electric equipment. The protocols used were all proprietary, meaning: components could not exchange information, manufacturers' equipment could not be mixed, so owners were held at gunpoint by control and equipment manufacturers for service, upgrades and additions. Building operators were faced with many different systems to learn and to maintain in order to operate their buildings.

29d.- Acknowledging Alarms

You can acknowledge a single alarm by clicking on the row to select it, then pressing the Acknowledge button in the command bar

30.- Pop-Up notifications

You can acknowledge the alarm by clicking on the ACKNOWLEDGE button. The CANCEL button will close the pop-up without acknowledging the alarm. Depending on the configuration of the alarm, the pop-up may not be closed until the alarm condition has reset. Some alarms may have an action assigned to them. Action could cause a specific System Group graphic ,a worksheet, or a file to open

17a.- BMS's servers provide

a) Storage for large amounts of data regarding system performance such as trends in ventilation flow amounts, fan operation, temperature, humidity, and pollutant measurements b)Software tools that permit operating personnel and regulatory agencies access to stored data: especially useful when trying to determine causes of IAQ problems c) Hosts for needed tools such as a computerized maintenance management system (CMMS) d) Software tools that send email alarms and alerts to operating personnel