CARLO GAVAZZI VariFlex3 RVLF Series User Manual

Motor Controllers AC Variable Frequency Drives Type VariFlex
3
RVLF
154 Specications are subject to change without notice. Pictures are just an example. For special features and/or customization, please ask to our sales network. 13/12/2017
Appendix 4: BACNet Protocol Description
BACnet is in compliance with four-layer of seven-layer structure models in OSI (Open Systems
Interconnection) of International Standard Organization (ISO). These four-layer structure models are
application layer, network layer, data link layer and physical layer. Besides, BACnet is definced by the
view of standard “object” and “property.” All BACnet devices are controlled via the property of objects.
Every controller with BACnet devices is considered an object collector so that every controller device can
execute different kinds of functions of objects to achieve the communication control and monitor control.
Services provide some commands to save or control information and some functions to achieve the
purpose of monitoring and control. Namely, one BACnet device reveive certain information or command
to complete specific work from other BACnet device so the two devices need to support the same service
to complete communication. To complete the exchange of these service messages, these communication
requirements are specified in the communication protocol of application layer by BACnet. Thus, services are
parts of the communication protocol data unit (PDU) in the application layer and build the communication
modes via the relationship of Server – Client. Client will send the message of sevice requirements to Server
and Server needs to respond to Client to execute this service. Refer to the following figure.
All BACnet devices have the application programs to manage the requirements of device motion and
executing services. Take work station for example, the application program needs to keep the display value
of every input so it requires sending the service request to the object of other device to update the display
value of input. The application program of the device needs to respond to the service requiremtents. Refer
to the following figure.
1. BACnet Services
Application
Layer
Network Layer
Data Link Layer
Physical Layer
Application Layer of BACnet
Network Layer of BACnet
ISO- 8802-2
(IEEE802.2)
ISO- 8802-3
(IEEE802.3)
ARCNET
MS/TP PTP
EIA-485 EIA-232
LonkTal
k
OSI Corresponding ModelBACnet Simple Model
Request
for PDU
Respond
to PDU
Receiv
e
Send
Receiv
e
Send
R
equest Respond
Client Server
Application
Program
Object
Object
Object
Object
BACnet Device
Request for
Service
Respond to
Service
Network
Service request
Read property
Service Reply?
BACnet Service
Request
Application Program
Application Layer
Network Layer
Data Link Layer
Physical Layer
A-BACnet.Request
N-UNITDATA.Request
DL-
UNITDATA.Request
MA-
UNITDATA.Request
P-UNITDATA.Request
APCI
Service
Data
APDU
NSDUNPCI NPDU
LSDU LPDULPCI
MSDUMPCI
PSDUPPCI
MPDU
PPDU
Application
Layer
Network Layer
Data Link Layer
Physical Layer
Application Layer of BACnet
Network Layer of BACnet
ISO- 8802-2
(IEEE802.2)
ISO- 8802-3
(IEEE802.3)
ARCNET
MS/TP PTP
EIA-485 EIA-232
LonkTal
k
OSI Corresponding ModelBACnet Simple Model
Request
for PDU
Respond
to PDU
Receiv
e
Send
Receiv
e
Send
R
equest Respond
Client Server
Application
Program
Object
Object
Object
Object
BACnet Device
Request for
Service
Respond to
Service
Network
Service request
Read property
Service Reply?
BACnet Service
Request
Application Program
Application Layer
Network Layer
Data Link Layer
Physical Layer
A-BACnet.Request
N-UNITDATA.Request
DL-
UNITDATA.Request
MA-
UNITDATA.Request
P-UNITDATA.Request
APCI
Service
Data
APDU
NSDUNPCI NPDU
LSDU LPDULPCI
MSDUMPCI
PSDUPPCI
MPDU
PPDU

CARLO GAVAZZI VariFlex3 RVLF Series Specifications

General

Brand	CARLO GAVAZZI
Model	VariFlex3 RVLF Series
Category	Controller
Language	English