BACnet/IP
The BACnet/IP protocol defines a number of services that are used to communicate between devices and the objects that are acted upon by those services.
|
Term |
Definition |
|---|---|
|
APDU |
Application protocol data unit, that data portion of a BACnet message. |
|
Confirmed message |
A message for which the device expects an answer. |
|
COV, COV increment |
Change of value, sets the amount by which a value must change for the meter to send a subscription notification. |
|
Device |
A BACnet device is a unit that is designed to understand and use BACnet protocol (for example, a BACnet-enabled meter or software program). It contains information about the device and device data in objects and object properties. Your meter is a BACnet device. |
|
Object |
Represents the device and device data. Each object has a type (for example, analog input or binary input) and has a number of properties. |
|
Present value |
The current value of an object. |
|
Property |
The smallest piece of information in BACnet communications, it consists of a name, data type, and value. |
|
Service |
Messages from one BACnet device to another. |
|
Subscription |
A relationship between a BACnet client and the meter, so that when the present value property of an object changes on the meter, a notification is sent to the client. |
|
Subscription notification |
The message the meter sends to indicate a COV event has occurred. |
|
Unconfirmed message |
A message for which the device does not expect an answer. |
|
BACnet Broadcast Management Device (BBMD) |
A BACnet/IP device (or software application) residing on a BACnet/IP subnet that sends BACnet broadcast messages from devices on its subnet to peer BBMDs and registered foreign devices on other subnets. |
|
Foreign device |
A BACnet/IP device (or software application) that resides on a remote IP subnet and registers with a BBMD to facilitate the sending and receiving of broadcast messages to/from devices accessible by the BBMD. |