Integrated Automation System Definitions and Abbreviations

Adjustable (Adj): A characteristic of a control logic parameter such that it can be varied by the operator without downloading the program.
Advanced Application Controller (AAC): A device with limited resources relative to the Building Controller (BC). It may support a level of programming and may also be intended for application specific applications.
Algorithm: A logical procedure for solving a recurring problem.
Analog: A continuously varying signal value (temperature, current, velocity, etc.).
Application Programming Tool: A vendor unique software tool used to create applications for programmable controllers. This software tool may also be used for system programming, controller commissioning, network management.
Application Protocol Data Unit (APDU): A unit of data specified in an application protocol and consisting of application protocol control information and possible application user data (ISO 9545).
Advanced Unitary Controller (AUC): Programmable or configurable control product that incorporates solid-state components based upon a microprocessor to perform multiple control loops or functions as part of a specific application. AUC shall conform to the <LONMARK^® certification, functional profiles and interoperability standards, BACnet/BTL certification and integration standards or MODBUS communication standards>.

<Note: It is important to define the intent of utilizing open protocols within the AUC. LonWorks, BACnet and MODBUS all offer different levels of “Open” and the designer must thoroughly understand the integration and long term operational requirements of each technology prior to designing the system>

ASCII Transmission Mode (MODBUS): MODBUS serial line communication mode using ASCII (American Standard Code for Information Interchange), each 8–bit byte in a message is sent as two ASCII characters. This mode is used when the physical communication link or the capabilities of the device does not allow the conformance with MODBUS RTU mode requirements regarding timer management. This mode is less efficient than RTU since each byte needs two characters.
BACnet or BACnet Standard: BACnet communication requirements as defined by ASHRAE/ANSI 135 and all current addenda and annexes.
BACnet Interoperability Building Blocks (BIBB): BIBB defines a small portion of BACnet functionality that is needed to perform a particular task. BIBBS are combined to build the BACnet functional requirements for a device in a Specification.
BACnet Touchscreen Communicating Thermostat (BCT): Configurable control product that incorporates solid-state components based upon a microprocessor to perform multiple control loops or functions as part of a specific application. AUC shall conform to the BACnet/BTL certification and integration standards.
Bandwidth Utilization: The average utilization of the network capacity. Generally speaking the amount of present network traffic as it relates to the maximum amount of traffic for which a network can support.
Binary: A two-state system where a high signal level represents an “on” condition and an “off” condition is represented by a low signal level.
Binding: In the general sense, binding refers to the associations or mappings of the sources network variables or objects and their intended or required destinations.The concept of associating an output network variable from one device to the input network variable of a second (third, fourth, etc.) device.
Bridge: A device that routes messages or isolates message traffic to a particular segment, sub-net or domain of the same physical communication media.
Broadcast Mode (MODBUS): The master can send a request to all slaves. No response is returned to broadcast requests sent by the master. The broadcast requests are writing commands. All MODBUS devices must accept the broadcast for writing function.
Bus Topology: A term used to describe the sequential connection of devices on a DLN segment. The communication cable runs from device to device with no tees or stubs from the main communication cable to a device.
Change of Value (COV): An event that occurs when a measured or calculated analog value changes by a predefined amount.
Channel: A DLN network consisting of two segments connected by a physical layer repeater or router configured as a repeater. Each segment can support a theoretical limit of 64 connections.
Client: A device that is the requestor of services from a server. A client device makes requests of and receives responses from a server device.
Commissioning: A process of ensuring that systems are installed, functionally tested, and capable of being operated and maintained to perform in conformity with design intent. Control System commissioning requires a point to point check out and the detail documentation of each parameter. Commissioning includes a complete functional test of the sequence of operation for each piece of equipment.
Continuous Monitoring: A sampling and recording of a variable based on time or change of state (e.g. trending an analog value, monitoring a binary change of state).
Control Wiring: Includes conduit, wire and wiring devices to install complete control systems including HVAC control, switchgear, uninterruptible power supplies, lighting, security, interlocks, thermostats, EP and IP switches and like devices. Includes all wiring from Intelligent Devices and Controllers to all sensors and points defined in the input/output summary shown on the drawings or specified herein and required to execute the sequence of operation.
Controller or Control Unit (CU): Intelligent stand-alone control panel. Controller is a generic reference and shall include NCs, PCUs, PICUs, PPCUs, UICUs, AACs, and AUCs as appropriate.
Control Systems Server (CSS): A computer that maintains the systems configuration and programming database. This may double as an operator workstation for smaller systems.
CRC Checking (MODBUS): The MODBUS RTU mode includes an error–checking field that is based on a Cyclical Redundancy Checking (CRC) method performed on the message contents.
DALI: Dimmable Addressable Lighting Interface.
Deadband: A temperature or lighting range over which no heating, cooling, or lighting energy is supplied, such as 72-74°F, i.e., as opposed to single point changeover or overlap.
Device instance: A number that uniquely identifies a device on the Device Level Network (DLN).

Direct Digital Control (DDC): Microprocessor-based control including Analog/Digital conversion and program logic.
Discrete: Binary or digital state.
Distributed Control: A system whereby control processing is decentralized and independent of a central computer.
Diagnostic Program: Machine-executable instructions used to detect and isolate system and component malfunctions.
DLN: Device Level Network – The local control system network that incorporates servers, control devices and software applications.
EEPROM: Electrically Erasable Programmable Read-Only Memory – non-volatile, user modifiable, read-only memory that can be erased and reprogrammed repeatedly through the application of a higher than normal electrical voltage.
FAC LAN: Facility Local Area Network.
FTT: Free Topology Transceiver – A LONWORKS^® standard hardware device that enables communication between nodes. The FTT transceiver facilitates interoperability by creating a media standard while allowing flexible network design through bus and free topologies.
Functional Profile: A collection of variables required to define key parameters for a standard application. For the HVAC industry, this includes applications like VAV terminal units, fan coil units, etc.
Gateway: A device, which contains two or more dissimilar networks/protocols, permitting information exchange between dissimilar systems.
Graphical User Interface (GUI): A Man Machine Interface device (PC, laptop or dumb display terminal) which incorporates web browsing for remote network client services as a thin client machine. The Graphical User Interfacing allows the operator to manage, command, monitor, configure and program the system. It shall function as the point of interface for all control and monitoring functions as well as all data logs, trends, and alarming.
Hand Held Device (HHD): Manufacturer’s microprocessor based device for direct connection to a Controller.
HTTP: Hypertext Transfer Protocol: the set of rules for exchanging data files (text, graphic images, sound, video and other multimedia files) over the Internet.
Integrated Automation System (IAS). The complete facility control system comprised of mechanical system automation, security control, lighting control, automatic temperature control, etc., as defined in the contract documents. The IAS is comprised of a <one-tier or two-tier> network structure. The second tier uses <LonTalk^â, MODBUS, BACnet, and approved proprietary protocols> for distributed control processing. The first tier uses <Ethernet, TCP/IP protocol in a 10/100 BaseT> wiring configuration. The IAS also includes interface panels, bridges, network controllers, LAN wiring, raceways, etc. All system data shall be made available to the Owner’s Non-Enterprise Wide Area Network for building management. The functionality of the system will allow building engineers the ability to view and modify the facility from any point on the Owner’s WAN.
Interface Panel: A device that contains an I/O software driver to translate data from a particular format to that conforming to <LonTalk^â, MODBUS, or BACnet> Also see Gateway.
Intelligent Sensor or Actuator (ISA’s): Control products that incorporate solid state components based around the Neuron chip to perform a single dedicated control loop or function (e.g.: actuators, sensors, switches). Device functional profiles are based on upon LONMARK^® International Association Standards.
IT LAN: Reference to the facility’s Information Technology network, used for normal business-related e-mail and Internet communication.
LAN: Local Area Network – a group of computers and/or associated devices which share a common communications line and typically share the resources of a single processor or server within a small geographic area.
LAN Interface Device (LANID): Device or function used to facilitate communication and sharing of data throughout the IAS.
LONWORKS^®: The generic technology that incorporates LONMARK^® certified products that communicate using LonTalkâ Communications protocol. The technology employs routers, gateways, bridges, and multimedia transceivers, permitting topology and media independent control solutions.
LonTalk^® Protocol: Protocol implemented on LONWORKS^® networks to standardize communications. It defines a standard way for devices to exchange information. The LonTalk protocol is an openly published non-proprietary protocol.
LONMARK^® International Association: An organization dedicated to issuing guidelines to ensure that devices from different vendors can coexist and operate on a single LONWORKS^® The organization establishes functional profiles and LONMARK^® certification to devices in order to ensure interoperability between vendors.
MAC address: The MAC (Media Address Control) address uniquely identifies a device on its MS/TP network.
Master Devices: Master devices can initiate requests for data but require more processing and memory capacity than slave devices.
Master-Slave/Token Passing (MS/TP) network segment: An electrically separate section of a network. An MS/TP network segment contains no more than 32 devices of any type. Repeaters connect the segments of an MS/TP network.
Maximum Send Time Parameter: A parameter used to ensure the periodic update of network data. If a time period equal to the value of this parameter has expired without a broadcast of the variable, a re-broadcast of the current value shall be executed. See also minimum send time parameter definitions.
Minimum Send Time Parameter: A parameter used to control unnecessary broadcasting of data onto the network. A broadcast of an updated value shall not occur unless a time period equal to the value of this parameter has expired. The expiration of the time period does not mandate a re-broadcast. See also maximum send time parameter definitions.
MODBUS: A standard that defines an application layer messaging protocol, positioned at level 7 of the OSI model that provides “client/server” communications between devices connected on different types of buses or networks. It standardizes a specific protocol to exchange MODBUS requests between a master and one or several slaves.
Network: A system of distributed control units and intelligent devices that are linked together on a communications bus. A network allows sharing of point information between all control units. Additionally, a network provides central monitoring and control of the entire system from any distributed control unit location.
Network Controller (NC): A Niagara N4 Network Controller that incorporates LONWORKS^®, BACnet and MODBUS network services host API to perform localized network management and network access services over a group of channel(s). Supervises groups of intelligent devices and Control Units to perform a global sequence of operation. Can be configured to serve as a SCADA client on the IAS, Tier 1, and Local Area Network. Provides integration to LONWORKS^®, BACnet, MODBUS, Enterprise level systems and other protocols. The NC serves four primary functions:
- Time Schedules: Time schedule algorithms shall reside in the NC. Occupancy/energize commands shall be broadcast to the building level controllers in the number required by the sequence of control.
- Trend Data Storage: The NC shall collect data from the building level controls at specified intervals and store the data for periodic uploading to the server. Polling communication techniques are acceptable for data collection by the network controller.
- Alarm Generation: The NC shall receive binary alarm variables from the building level controllers and transmit this data to the alarm handling software module within the server and operator work stations. Receipt of alarm data from the building level controls shall be based on broadcasting from the building level controls and not based on polling by the Network Controller.
- Interlock and control: The network controller shall perform sequence of operation logic and control where appropriate.
Node: a Device connected to a communications network.
NCI: LONWORKS^® Network Configuration Parameter: An input network variable to a controller that is written to the EEPROM. Configuration parameters can be changed periodically from the HMI or a network management tool but are not changed routinely as a function of control logic.
Niagara Compatibility Statement. (NiCS): Niagara N4 includes a licensing model that provides OEMs with the ability to define the various levels and types of Niagara N4 interoperability that their products will support. The feature is referred to as the Niagara N4 Compatibility Statement or NiCS. There are two primary interactions that the NiCS addresses – the sharing of data between stations (JACEs and Supervisors) and the ability for a tool (i.e., WorkPlace N4) to engineer a station.
NV: LONWORKS^® Network Variable.
NVI: LONWORKS^® Network Variable Input.
NVO: LONWORKS^® Network Variable Output.
Open Database Connectivity (ODBC): An open standard application-programming interface (API) for accessing a database. ODBC compliant systems make it possible to access any data from any application, regardless of which database management system (DBMS) is handling the data.
Operator Interface (OI): A device used by the operator to manage the BAS including OWSs, POTs, and HHDs.
Operating System (OS): Software which controls the execution of computer programs and which provides scheduling, debugging, input/output controls, accounting, compilation, storage assignment, data management, and related services.
Operator Workstation (OWS): A Man Machine Interface device (PC, laptop or dumb display terminal) which incorporates web browsing for remote network client services. As the BAS network devices are stand-alone, the OWS is not required for normal operation.
Override NVI: LONWORKS^® Network Variable Input which has the ability to accept a user inputted override value.
PAD router: A BACnet IP PAD is a special type of router that connects two or more BACnet networks that are separated by at least one IP-only router.
Peer to Peer: Mode of communications between controllers in which each device connected to the network has equal status and each shares its database values with all other devices connected to network as defined in the LonMark standard.
Peripheral: Input/Output equipment used to communicate to and from the computer and make hard copies of system outputs and electronic files. Peripherals include CRT, printer, hard drives, disk drives, modems, etc.
Point: Analog or discrete instrument with addressable database values.
Point-to-Point (PTP): Serial communication as defined in the BACnet standard.
Polling: The concept of a control device requesting a network variable from a second control device at a specified interval. Polling communication is typically used to populate dynamic data on an active graphic page and for temporary or short term trending of data where the trend data is not stored at the controller level.
Portable Operators Terminal (POT): Laptop PC used both for direct connection to a controller and for remote dial up connection.
Protocol Implementation Conformance Statement (PICS): A written document, created by the manufacturer of a device, which identifies the particular options specified by BACnet that are implemented in the device.
Programmable IP Control Unit (PICU): IP control product that incorporates solid state components based upon a microprocessor to perform multiple control loops or functions as part of applications that can be entered as part of the controller commissioning/programming. PICU shall conform to BACnet/BTL Certification and integration standards. IP network communication shall be FoxS or BACnet IP. Proprietary communication protocols may NOT be utilized in Programmable IP Control Units.
Programmable Plant Control Unit (PPCU): IP control product that incorporates solid state components based upon a microprocessor to perform multiple control loops or functions as part of applications that can be entered as part of the controller commissioning/programming. PPCU shall conform to the LONMARK^® certification, functional profiles and interoperability standards, BACnet/BTL Certification and integration standards, and/or MODBUS integration standards. Proprietary communication protocols may NOT be utilized in Programmable Plant Control Units.
Repeater: A physical device used to connect two segments while amplifying, conditioning, or strengthening the signal. A Repeater does not provide any routing or filtering of network traffic.
Router: A device which routes or forwards messages destined for a node on another subnet or domain of the DLN. The device controls message traffic based on node address and priority. Routers also serve as communication interfaces between power line, twisted pair and RF media.
RS-232: EIA/TIA-232 Standard
RS-485: EIA/TIA-485 Standard
RTU Transmission Mode (MODBUS): When devices communicate on a MODBUS serial line using the RTU (Remote Terminal Unit) mode, each 8–bit byte in a message contains two 4–bit hexadecimal characters. The main advantage of this mode is that its greater character density allows better data throughput than ASCII mode for the same baud rate. Each message must be transmitted in a continuous stream of characters.
Secure Socket Layer (SSL): A commonly used protocol for managing the security of messages transmission on the Internet.
Server: A device that is a provider of services to a client. A client device makes requests of and receives responses from a server device.
Simple Object Access Protocol (SOAP): A method for a program running in one type of operating system to communicate with a program on the same or different type of operating system by using the World Wide Web’s Hyper Text Transfer Protocol (HTTP) and its Extensible Markup Language (XML) as the mechanisms for information exchange.
Slave Devices: Slave devices cannot initiate requests for data; they can reply only to messages from other devices. They are best suited for simple, low-cost functions.
Smart Device: A control I/O device such as a sensor or actuator that can directly communicate with the controller network to which it is connected. This differs from an AUC in that it typically deals only with one variable (e.g. a single relay output).
Solenoid: Electric two-position actuator.
Standard Network Variable Type (SNVT): A data format statement for implicit ‘open’ communication on a LonTalk^® This can either be simple SNVT (which defines the format of a single piece of data) or Structured SNVT (which defines the format of a network variable that contains several different data elements).
Structured Query Language (SQL): A standard interactive and programming language for retrieving information from and for updating a database via an organized series of queries.
Stand-Alone Controller: A stand-alone controller has provisions for all of the physical inputs and physical outputs associated with a single mechanical component such as a terminal unit, air handling unit, chiller or boiler. The controller shall also have embedded in it all of the control logic that associated the physical inputs to the physical outputs. A stand-alone controller may rely on other networked devices for time schedule inputs and trend data storage.
Supervising Control and Data Acquisition (SCADA) Node: An MMI incorporating a graphical object oriented user interface software application which provides supervisory control and data acquisition from a high level processing personnel computer.
Supervisory Logic: The concept of gathering performance data from multiple terminal units to determine if a specific condition exists within the family of terminal devices.
Terminator: An electric component that consists of a resistive and capacitive circuit specifically designed to enhance the quality of communication on a segment. On a bus topology, terminators are connected to both ends of a segment. On MS/TP and free topology network segments a single terminator is required. The terminator is placed at the end-of-line for the MS/TP network segment.
Trend Log: A trend log is a collection of samples from a specified variable that are stored within a device on the IAS This data may be periodically sent up to or requested by a Network Controller or an Operator Workstation for the purpose of report generation.
Unicast Mode (MODBUS): The master addresses an individual slave. After receiving and processing the request, the slave returns a message (a ‘reply’) to the master.
Unitary IP Control Unit (UICU): IP control product that incorporates solid state components based upon a microprocessor to perform multiple control loops or functions as part of applications that can be entered as part of the controller commissioning/programming. UICU shall conform to BACnet/BTL Certification and integration standards. IP network communication shall be FoxS or BACnet IP. Proprietary communication protocols may NOT be utilized in Unitary IP Control Units.
WAN: Wide Area Network – Internet-based network connecting multiple facilities with a central data warehouse and server, accessible via standard web-browser.
XML (Extensible Markup Language): A specification developed by the World Wide Web Consortium. XML is a pared-down version of SGML, designed especially for Web documents. It allows designers to create their own customized tags, enabling the definition, transmission, validation, and interpretation of data between applications and between organizations.

AHU Air Handling Unit

AI Analog Input

ANSI American National Standards Institute

AO Analog Output

Approx. Approximately

AUC Advanced Unitary Controller

ASHRAE American Society of Heating, Refrigerating, and Air Conditioning Engineers

ASPE American Society of Plumbing Engineers

ASME American Society of Mechanical Engineers

ASTM American Society for Testing and Materials

ATC Automatic Temperature Control System

AWG American Wire Gauge (Standard)

BAS Building Automation System

BCT BACnet Touchscreen Communicating Thermostat

BMS Building Management System

CAD Computer Aided Design

CCC Central Communications Controller

CCU Central Control Unit

Contr. Contractor

COS Change of State

CPU Central Processing Unit

CRAC Computer Room Air Conditioning

CRT Cathode Ray Tube

DALI Digital Addressable Lighting Interface

DCP Digital Control Panel

DDC Direct Digital Controls

Deg. C or °C Degree Celsius

DI Discrete or Digital Input

Dia. or diam. Diameter

DMA Direct Memory Access

DO Discrete or Digital Output

Dpr. Damper

Dwgs. Drawings

EP Electric-pneumatic

EMCS Energy Management Control System

FAC LAN Facility Local Area Network

FPB Fan powered (VAV) box

FPM Feet per minute

FACP Fire Alarm Control Panel

FCC Fire Command Center

FCIP Firefighters’ Control and Indicating Panel

FMS Facility Management System

Galv. Galvanized

GUI Graphical User Interface

HVAC Heating Ventilating and Air Conditioning

IAS Integrated Automation System

I/O Input/Output

ISA Intelligent Sensor or Actuator

LNS LONWORKS^® Network Services

NC Network Controller

NSS Network Services Server

NSI Network Services Interface

Mfr. Manufacture

Mfgr. Manufacturer

Max. Maximum

Min. Minimum or Minute

MMI Man-Machine Interface

MSCP Mass Storage Control Protocol

MSI Master System Integrator

NCP Network Control Panel

NEC National Electrical Code

NI Network Integrator

NIC Not in Contract

NFPA National Fire Protection Association

O.C. On Center

O.D. Outside Diameter

OS Operating System

PE Pneumatic-electric

Per According to, in accordance with

PICU Programmable IP Control Unit

PPCU Programmable Plant Control Unit

PRV Pressure Reducing Valve

Provide Furnish and install

RAM Random Access Memory

ROM Read Only Memory

RTD Resistance Temperature Device

SCADA Supervisory Control and Data Acquisition System

SI Systems Integrator

SNVT Standard Network Variable Type

TCP/IP Transmission Control Protocol / Internet Protocol

THHN Thermoplastic High Heat Resistant Nylon Coated-Cable coating

TP Twisted Pair

UBC Uniform Building Code

UICU Unitary IP Control Unit

UL Underwriters’ Laboratory

UMC Uniform Mechanical Code

UML Unified Modeling Language

UPS Uninterruptible Power Supply

VAV Variable Air Volume

VCS Voice Communication System

VFD Variable Frequency Drive

XIF LONMARK^® Product Information Files

XML Extensible Markup Language

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Integrated Automation System Definitions and Abbreviations