WEG Electric CFW501 Users Manual
BACnet
CFW501
Motors I Automation I Energy I Transmission & Distribution I Coatings
User’s Manual
BACnet User’s Manual
Series: CFW501
Language: English
Document Number: 10002041146 / 00
Publication Date: 09/2013
Contents
CONTENTS
CONTENTS ......................................................................................................................... 3
ABOUT THE MANUAL ....................................................................................................... 5
ABBREVIATIONS AND DEFINITIONS ......................................................................................................... 5
NUMERICAL REPRESENTATION ............................................................................................................... 5
DOCUMENTS ................................................................................................................................................ 5
1 INTRODUCTION TO THE SERIAL COMMUNICATION .............................................. 6
2 INTRODUCTION TO THE BACNET COMMUNICATION ............................................ 7
2.1 BACNET MS/TP ................................................................................................................................. 8
2.1.1 BACnet MS/TP Message Structure .......................................................................................... 8
2.2 ADDRESS ......................................................................................................................................... 10
2.3 BACNET PROFILE ........................................................................................................................... 10
2.3.1 ReadProperty (DS-RP-B) ......................................................................................................... 10
2.3.2 WriteProperty (DS-WP-B) ........................................................................................................ 10
2.3.3 WHO IS / I AM (DM-DDB-B) .................................................................................................... 10
2.3.4 Device Management-Reinitialize Device-B (DM-RD-B) ....................................................... 10
3 INTERFACE DESCRIPTION ....................................................................................... 11
3.1 PLUG-IN MODULES ........................................................................................................................ 11
3.1.1 Standard plug-in module with two RS485 interfaces (CFW500- CRS485) ......................... 11
3.1.2 Additional plug-in modules ..................................................................................................... 12
3.2 RS485................................................................................................................................................ 12
3.2.1 RS485 Interface Characteristics ............................................................................................ 12
3.2.2 Terminating resistor ................................................................................................................ 12
3.2.3 Indications ................................................................................................................................ 12
3.2.4 Connection with the RS485 Network ..................................................................................... 12
4 PROGRAMMING ........................................................................................................ 13
4.1 SYMBOLS FOR THE PROPERTIES DESCRIPTION ...................................................................... 13
P0105 – 1ST/2ND RAMP SELECTION .......................................................................................................... 13
P0220 – LOCAL/REMOTE SELECTION SOURCE .................................................................................... 13
P0221 – SPEED REFERENCE SELECTION – LOCAL SITUATION ......................................................... 13
P0222 – SPEED REFERENCE SELECTION – REMOTE SITUATION ...................................................... 13
P0223 – FORWARD/REVERSE SELECTION – LOCAL SITUATION ........................................................ 13
P0224 – RUN/STOP SELECTION – LOCAL SITUATION .......................................................................... 13
P0225 – JOG SELECTION – LOCAL SITUATION ..................................................................................... 13
P0226 – FORWARD/REVERSE SELECTION – REMOTE SITUATION .................................................... 13
P0227 – RUN/STOP SELECTION – REMOTE SITUATION ...................................................................... 13
P0228 – JOG SELECTION – REMOTE SITUATION .................................................................................. 13
P0308 – SERIAL ADDRESS ........................................................................................................................ 13
P0310 – SERIAL BAUD RATE .................................................................................................................... 14
P0311 – SERIAL INTERFACE BYTE CONFIGURATION .......................................................................... 14
P0312 – SERIAL PROTOCOL ..................................................................................................................... 15
P0313 – COMMUNICATION ERROR ACTION .......................................................................................... 16
P0314 – SERIAL WATCHDOG ................................................................................................................... 16
P0316 – SERIAL INTERFACE STATUS ..................................................................................................... 17
P0680 – STATUS WORD ............................................................................................................................ 17
P0681 – MOTOR SPEED IN 13 BITS ......................................................................................................... 19
P0682 – SERIAL CONTROL WORD ........................................................................................................... 19
P0683 – SERIAL SPEED REFERENCE ...................................................................................................... 20
P0695 – DIGITAL OUTPUT SETTING ........................................................................................................ 21
CFW501 | 3
Contents
P0696 – VALUE 1 FOR ANALOG OUTPUTS ............................................................................................. 22
P0697 – VALUE 2 FOR ANALOG OUTPUTS ............................................................................................. 22
P0698 – VALUE 3 FOR ANALOG OUTPUTS ............................................................................................. 22
P0760 – BACNET EQUIPMENT INSTANCE – HIGH PART ...................................................................... 22
P0761 – BACNET EQUIPMENT INSTANCE – LOW PART ....................................................................... 23
P0762 – MAXIMUM MASTER NUMBER ................................................................................................... 24
P0763 – MAXIMUM NUMBER OF MS/TP FRAMES ................................................................................. 24
P0764 – I AM TRANSMISSION .................................................................................................................. 24
P0765 – NUMBER OF RECEIVED TOKENS.............................................................................................. 25
5 BACNET OBJECT MODELING .................................................................................. 26
5.1 BACNET OBJECTS .......................................................................................................................... 27
5.1.1 ANALOG INPUT OBJECT ........................................................................................................ 27
5.1.2 ANALOG OUTPUT OBJECT .................................................................................................... 27
5.1.3 ANALOG VALUE OBJECT ....................................................................................................... 27
5.1.4 BINARY INPUT OBJECT .......................................................................................................... 28
5.1.5 BINARY OUTPUT OBJECT ...................................................................................................... 28
5.1.6 BINARY VALUE OBJECT ......................................................................................................... 29
5.1.7 DEVICE OBJECT ...................................................................................................................... 29
5.1.8 Mailbox ...................................................................................................................................... 30
6 FAULTS AND ALARMS RELATED TO THE BACNET COMMUNICATION.............. 31
A128/F228 – TIMEOUT FOR SERIAL COMMUNICATION ....................................................................... 31
CFW501 | 4
About the Manual
ASCII
PLC
HMI
ro
rw
Document
Version
Source
Standard 135-2004
1.0
ANSI/ASHRAE/ISO
ABOUT THE MANUAL
This manual provides the necessary information for the operation of the CFW501 frequency inverter using the
BACnet protocol. This manual must be used together with the CFW501 user manual.
ABBREVIATIONS AND DEFINITIONS
American Standard Code for Information Interchange
Programmable Logic Controller
Human-Machine Interface
Read-only
Read/write
NUMERICAL REPRESENTATION
Decimal numbers are represented by means of digits without suffix. Hexadecimal numbers are represented with
the letter ‘h’ after the number.
DOCUMENTS
The BACnet protocol for the CFW501 was developed based on the following specifications and documents:
In order to obtain this documentation, consult BACnet ORG, witch is the organization that currently maintains,
publishes and updates the information regarding the BACnet network.
CFW501 | 5
Introduction to the Serial Communication
1 INTRODUCTION TO THE SERIAL COMMUNICATION
In a serial interface, the data bits are sent sequentially through a communication channel, or busbar. Several
technologies use serial communication for data transfer, including the RS232 and RS485 interfaces.
The standards that specify the RS232 and RS485 interfaces, however, do specify neither the format nor the
character sequence for data transmission and reception. In this sense, besides the interface, it is also necessary
to identify the protocol used for the communication.
The BACnet MS/TP network defines the BACnet message exchange using the RS485 interface as the physical
layer.
The characteristics of the RS485 serial interfaces available in the CFW501 frequency inverter, as well as the
BACnet protocol, will be presented next.
CFW501 | 6
Introduction to the BACnet Communication
2 INTRODUCTION TO THE BACNET COMMUNICATION
BACnet, acronym for "Building Automation Control Network", is a protocol defined by the ANSI/ASHRAE/ISO
Standard 135-2004. The protocol defines a model for building-automation, describing the interaction between
devices and systems. The protocol defines:
Data and commands structured in an object-oriented model;
Services that describe the access to data;
A flexible network architecture.
The BACnet standard defines six types of communication networks for transporting BACnet messages, as
showed in the Figure 2.1. The type of network defines the physical and data link layers. The six types of
networks are:
BACnet ARCnet;
BACnet Ethernet;
BACnet Lontalk;
BACnet MS/TP;
BACnet Point-to-Point;
BACnet IP;
Figure 2.1: BACnet protocol architecture
A BACnet equipment contains an information collection defined as objects and properties.
A BACnet object represents physical or virtual information of the equipment, as a digital or analog input, control
variables and parameters. The BACnet standard defines 25 types of objects. Each object is identified by a
propriety called Object Identifier, which codifies the object instance type in a 32-bit binary number.
A BACnet property represents characteristics or information of a BACnet object. It is through the properties that
other elements can access the equipment information. The property access can be defined as read-only or
writing/reading. The BACnet specification defines services that are grouped in five categories:
Object access
Device Management
Alarm and event
File transfer
Virtual terminal
BACnet equipments can be classified in six different profiles according to the set of services made available:
BACnet Operator Workstation (B-OWS)
BACnet Building Controller (B-BC)
BACnet Advanced Application Controller (B-AAC)
BACnet Application Specific Controller (B-ASC)
BACnet Smart Actuator (B-AS)
BACnet Smart Sensor (B-SS)
CFW501 | 7
Introduction to the BACnet Communication
Master/Slave (MS):
Token passing (TP)
Reception (RX):
Transmission (TX):
2.1 BACNET MS/TP
In the CFW501, the BACnet protocol was developed using the RS485 standard for the physical and data link
layers, called BACnet MS/TP (Master Slave/Token Passing). BACnet MS/TP nodes can be divided into two
groups, master nodes and slave nodes, according to the node address range.
The access control to the communication mean is performed in two ways:
that has the token can establish communication with slave nodes and other masters.
In a BACnet MS/TP network, the nodes are initialized and enter the IDLE state, waiting for the arrival of a
telegram, which can be:
Invalid frame: it remains in IDLE;
Not desired frame: it remains in IDLE;
Token: it enters the USE TOKEN state, executes the necessary communication (with slaves or other
masters) and passes the token to the next node;
Reception of a Poll of Master: it sends a telegram to the node with the address in the Source Address field;
Reception of a DataNoReplay: it signalizes the reception to the higher layers;
Reception of a DataNeedingReplay: it signalizes the reception to the higher layers and sends the requested
response.
It is used in the communication between a master node and a slave node;
: Communication only among master nodes. A logical ring is defined and the master
2.1.1 BACnet MS/TP Message Structure
The BACnet specification defines that the frame can have from 0 up to 501 bytes (octets), and that each byte is
composed by 8 bits without parity, with start and stop bits, as showed in the Figure 2.2.
Figure 2.2: Byte structure
between frames (Tturnaround) after the last byte stop bit is of 40-bit times, according to the
The maximum time between bytes (Tframegap) is of 20-bit times, and the minimum time
Figure 2.3.
The RTS signal must be disabled after the end of the stop bit time (Tpostdrive), which is of
15-bit times.
Figure 2.3: BACnet data reception
Header and data, as Figure 2.4 illustrates, form the BACnet data frame.
CFW501 | 8
Introduction to the BACnet Communication
HEADER
DATA
Frame
type
Destination
address
Source
address
Preamble:
Frame type:
Destination and source addresses:
Length:
Header CRC:
Data:
Data CRC:
0x55 0xFF
Figure 2.4: BACnet Frame
Length Length CRC Data CRC CRC
It is formed by two bytes with the 55h and FFh values respectively.
The BACnet specification defines eight frame types, from 0 to 7. Frame Types 8 through 127 are
reserved for the specification improvement, and from 128 through 255 are reserved for each vendor specific
frames. The defined types are:
0 Token
1 Poll for master
2 Reply to poll for master
3 Test request
4 Test response
5 BACnet data expecting reply
6 BACnet data not expecting reply
7 Reply postponed
Only master nodes must acknowledge frame types 0, 1 and 2, the slave nodes must ignore them.
Token (0) frame type: it is used in the relationship between master nodes. It does not present data. The master
node that has the token can initiate the communication. After sending the maximum number of data frames
(Nmax_info_frames) and waiting any expected replies, it must pass the token to the next master.
Poll for Master (1) frame type: It is transmitted periodically during the configuration. It is used to discover the
presence of other masters in the network and to determine the token sequence. Master nodes must respond
and slave nodes must ignore it. It does not present data.
Reply to Poll for Master (2) frame type: It is the response of the master nodes to the Poll for Master (frame type
1). It does not present data.
Test Request (3) frame type: It is used to start the communication in the MS/TP network. It is applied to send a
particular piece of information to a node.
Test Response (4) frame type: It is the response to a Test Request.
BACnet Data Expecting Reply (5) frame type: It is used by master nodes to convey the data parameter of a
DL_UNITDATA.request that presents destination address, data, priority and message code, waiting for a
response from the destination node.
BACnet Data not Expecting Reply (6) frame type: It is used by master nodes to convey the data parameter of a
DL_UNITDATA.request that presents destination address, data, priority and message code. It does not wait for
a response from the destination node.
Reply Postponed (7) frame type: It is used by master nodes to indicate that the response to a Data Expecting
Reply frame will be sent later. It does not present data.
It is formed by two bytes, destination and source, respectively.
It is formed by two bytes that inform the number of data bytes in the message.
The last part of the header is the fields for checking header transmission errors. The used
method is the CRC-8 (Cycling Redundancy Check).
It may present from 0 to 501 bytes, according to the BACnet specification. Data in the CFW501 can
present up to 59 bytes.
The last part of the telegram is the field for checking data transmission errors. The used method is
the CRC-16 (Cycling Redundancy Check).
CFW501 | 9
Introduction to the BACnet Communication
2.2 ADDRESS
It presents an address range from 0 to 254, where:
The range from 0 to 127 is reserved for master or slave nodes;
The range from 128 to 254 is used only by slave nodes.
The broadcast telegram must have FFh (255) in the destination address field.
The serial address is set using parameter P0308 in the CFW501.
2.3 BACNET PROFILE
The BACnet profile developed for the CFW501 is the B-ASC, with communication management services and
data sharing that presents the following BIBBs (BACnet interoperability Building Blocks):
DATA SHARING:
DS-RP-B: ReadProperty;
DS-WP-B: WriteProperty.
DEVICE and NETWORK MGMT:
DM-DDB-B: WHO IS / I AM;
DM-RD-B: Device Management-Reinitialize Device-B.
2.3.1 ReadProperty (DS-RP-B)
A BACnet client (node performing a request to a server node) uses the ReadProperty service to obtain a BACnet
object property value. This service allows reading access to the properties that have the R (reading) access
type.
2.3.2 WriteProperty (DS-WP-B)
A BACnet client uses the WriteProperty service to modify the value of a specific BACnet object property. This
service allows writing access to the properties that have the W (write) or C (commandable) access type.
2.3.3 WHO IS / I AM (DM-DDB-B)
The WHO IS / I AM service is used to identify the devices connected to the network. The WHO IS message is
sent by the BACnet controller, and the nodes respond with an I AM message, informing their Object Identifier
and address. The I AM message is transmitted in broadcast, and can be transmitted during initialization or
continuous, according to the parameter P0764.
2.3.4 Device Management-Reinitialize Device-B (DM-RD-B)
The Reinitialize Device service is used to remotely reinitialize the equipment, and uses a password to validate the
service execution. The BACnet standard defines that the password is a string (set of ASCII characters) with up
to 20 positions. The password used for the CFW501 remote reinitialization is the same one used to allow the
access for parameter content modifications, informed in the parameter P0000. This password can be a number
between 0000 and 9999.
The BACnet password for the CFW501 is a 4-character string. Therefore, the BACnet password can be a
number between 0000 and 9999. E.g., considering that the CFW501 default password is 5, the remote
reinitialization service will only be executed if the received password is “0005”.
CFW501 | 10
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