Anybus Communicator Modbus plus User manual

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HMS Industrial Networks
Mailing address: Box 4126, 300 04 Halmstad, Sweden
Visiting address: Stationsgatan 37, Halmstad, Sweden
Connecting DevicesTM
E-mail: [email protected]
Web: www.anybus.com
User Manual
Anybus®Communicator™ for Modbus Plus
Doc. Id. SCM-1200-093
Rev. 3.01

Important User Information
This document contains a general introduction as well as a description of the technical features provided by the
Anybus Communicator, including the PC-based configuration software.
The reader of this document is expected to be familiar with PLC and software design, as well as communication
systems in general. The reader is also expected to be familiar with the Microsoft Windows operating system.
Liability
Every care has been taken in the preparation of this manual. Please inform HMS Industrial Networks AB of any
inaccuracies or omissions. The data and illustrations found in this document are not binding. We, HMS Industrial
Networks AB, reserve the right to modify our products in line with our policy of continuous product development.
The information in this document is subject to change without notice and should not be considered as a commit-
ment by HMS Industrial Networks AB. HMS Industrial Networks AB assumes no responsibility for any errors that
may appear in this document.
There are many applications of this product. Those responsible for the use of this device must ensure that all the
necessary steps have been taken to verify that the applications meet all performance and safety requirements in-
cluding any applicable laws, regulations, codes, and standards.
HMS Industrial Networks AB will under no circumstances assume liability or responsibility for any problems that
may arise as a result from the use of undocumented features, timing, or functional side effects found outside the
documented scope of this product. The effects caused by any direct or indirect use of such aspects of the product
are undefined, and may include e.g. compatibility issues and stability issues.
The examples and illustrations in this document are included solely for illustrative purposes. Because of the many
variables and requirements associated with any particular implementation, HMS Industrial Networks AB cannot
assume responsibility for actual use based on these examples and illustrations.
Intellectual Property Rights
HMS Industrial Networks AB has intellectual property rights relating to technology embodied in the product de-
scribed in this document. These intellectual property rights may include patents and pending patent applications
in the US and other countries.
Trademark Acknowledgements
Anybus ® is a registered trademark of HMS Industrial Networks AB. All other trademarks are the property of their
respective holders.
Warning: This is a class A product. in a domestic environment this product may cause radio interference in
which case the user may be required to take adequate measures.
ESD Note: This product contains ESD (Electrostatic Discharge) sensitive parts that may be damaged if ESD
control procedures are not followed. Static control precautions are required when handling the prod-
uct. Failure to observe this may cause damage to the product.
Modbus Plus protocol mode for Anybus Communicator
Rev 3.01
Copyright© HMS Industrial Networks AB
Sept 2011 Doc Id SCM-1200-093

Doc.Id. SCM-1200-093
Anybus Communicator for Modbus Plus
Doc.Rev. 3.01
Preface About This Document
Related Documents.................................................................................................................................. 5
Document History ................................................................................................................................... 5
Conventions & Terminology.................................................................................................................. 6
Glossary ..................................................................................................................................................... 6
Sales and Support ..................................................................................................................................... 7
Chapter 1 About the Anybus Communicator Modbus Plus
External View ........................................................................................................................................... 9
Status LEDs ............................................................................................................................................ 10
Configuration Switches ......................................................................................................................... 11
Hardware Installation ............................................................................................................................ 12
Software Installation .............................................................................................................................. 13
Anybus Configuration Manager..................................................................................................... 13
Chapter 2 Basic Operation
General..................................................................................................................................................... 14
Data Exchange Model ........................................................................................................................... 15
Memory Map................................................................................................................................. 15
Data Exchange Example.............................................................................................................. 16
Subnetwork Protocol............................................................................................................................. 17
Protocol Modes............................................................................................................................... 17
Protocol Building Blocks ................................................................................................................ 17
Master Mode ................................................................................................................................. 18
Generic Data Mode ....................................................................................................................... 19
DF1 Master Mode ........................................................................................................................ 19
Data Representation on Modbus Plus ................................................................................................ 20
General.......................................................................................................................................... 20
Data Types.................................................................................................................................... 20
Memory Layout (Internal Memory Buffer)...................................................................................... 20
Supported Modbus Commands....................................................................................................... 21
Modbus Register Map.................................................................................................................... 21
Point-to-Point Exception Handling................................................................................................ 21
Chapter 3 Navigating the Anybus Configuration Manager
Main Window ......................................................................................................................................... 22
Pull-down Menu ............................................................................................................................ 23
Toolbar Icons ................................................................................................................................. 26
Table of Contents
Table of Contents

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Chapter 4 Basic Settings
Fieldbus Settings..................................................................................................................................... 27
ABC Parameters ..................................................................................................................................... 28
Subnetwork Parameters......................................................................................................................... 30
Chapter 5 Nodes
General..................................................................................................................................................... 31
Adding & Managing Nodes.................................................................................................................. 31
Node Parameters.................................................................................................................................... 31
Master Mode and Generic Data Mode........................................................................................... 31
Chapter 6 Transactions
General..................................................................................................................................................... 32
Adding & Managing Transactions....................................................................................................... 33
Transaction Parameters (Master Mode).............................................................................................. 34
Parameters (Query & Broadcast)................................................................................................... 34
Parameters (Response).................................................................................................................... 36
Transaction Parameters (Generic Data Mode).................................................................................. 36
Produce-Transactions ..................................................................................................................... 36
Consume-Transactions ................................................................................................................... 37
Transaction Editor ................................................................................................................................. 38
Chapter 7 Frame Objects
General..................................................................................................................................................... 39
Adding and Editing Frame Objects .................................................................................................... 39
Constant Objects (Byte, Word, Dword)............................................................................................. 40
Limit Objects (Byte, Word, Dword) ................................................................................................... 41
Data Object ............................................................................................................................................. 42
Variable Data Object ............................................................................................................................. 42
Checksum Object ................................................................................................................................... 44
Chapter 8 Commands
General..................................................................................................................................................... 45
Adding & Managing Commands ......................................................................................................... 45
Pull-Down Menu........................................................................................................................... 46
Toolbar Icons ................................................................................................................................. 46
The Command Editor ........................................................................................................................... 47
General.......................................................................................................................................... 47
Basic Navigation ........................................................................................................................... 47
Pull-down Menu ............................................................................................................................ 48
Editing a Command ...................................................................................................................... 49
Example: Specifying a Modbus-RTU Command in Master Mode ................................................. 50

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Chapter 9 DF1 Protocol Mode
General..................................................................................................................................................... 51
ABC Parameters ..................................................................................................................................... 52
Subnetwork Parameters......................................................................................................................... 53
Node Parameters.................................................................................................................................... 54
Services .................................................................................................................................................... 54
Available Services .......................................................................................................................... 55
Integrity Check ....................................................................................................................................... 56
Read Diagnostics.................................................................................................................................... 56
Read Data ................................................................................................................................................ 57
Write Data ............................................................................................................................................... 57
Chapter 10 Subnetwork Monitor
Chapter 11 Node Monitor
General..................................................................................................................................................... 59
Navigating the Node Monitor.............................................................................................................. 60
Pull-Down Menu........................................................................................................................... 61
Toolbar Icons ................................................................................................................................. 62
Chapter 12 Data Logger
General..................................................................................................................................................... 63
Operation................................................................................................................................................. 63
Configuration .......................................................................................................................................... 64
Chapter 13 Configuration Wizards
General..................................................................................................................................................... 65
Selecting a Wizard Profile ..................................................................................................................... 65
Wizard - Modbus RTU Master ............................................................................................................ 66
Chapter 14 Control and Status Registers
General..................................................................................................................................................... 67
Handshaking Procedure ................................................................................................................. 67
Data Consistency ........................................................................................................................... 68
Status Register Contents (Gateway to Control System)................................................................... 69
General Information....................................................................................................................... 69
Status Codes in Master Mode and DF1 Master Mode................................................................... 69
Status Code in Generic Data Mode ............................................................................................... 70
Control Register Contents (Control System to Gateway)................................................................ 71
General Information....................................................................................................................... 71
Control Codes in Master Mode and DF1 Master Mode................................................................. 71
Control Codes in Generic Data Mode ............................................................................................ 71

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Chapter 15 Advanced Fieldbus Configuration
General..................................................................................................................................................... 72
Mailbox Editor........................................................................................................................................ 72
Appendix A Connector Pin Assignments
Modbus Plus Connector ....................................................................................................................... 73
Power Connector ................................................................................................................................... 73
PC Connector ......................................................................................................................................... 74
Subnetwork Interface ............................................................................................................................ 75
General Information....................................................................................................................... 75
Bias Resistors (RS485 Only)......................................................................................................... 75
Termination (RS485 & RS422 Only) ......................................................................................... 75
Connector Pinout (DB9F) ............................................................................................................. 75
Typical Connection (RS485).......................................................................................................... 76
Typical Connection (RS422 & 4-Wire RS485) ........................................................................... 76
Typical Connection (RS232).......................................................................................................... 76
Appendix B Technical Specification
Mechanical Properties............................................................................................................................ 77
Electrical Characteristics ....................................................................................................................... 77
Environmental Characteristics ............................................................................................................. 77
Regulatory Compliance ......................................................................................................................... 78
Appendix C Troubleshooting
Appendix D ASCII Table

Doc.Id. SCM-1200-093
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Doc.Rev. 3.01
Preface
About This Document
For more information, documentation etc., please visit the HMS website, www.anybus.com.
Related Documents
Document History
Summary of Recent Changes (3.00... 3.01)
Revision List
Document name Author
ABC-MBP Installation Leaflet HMS
DF1 Protocol and Command Set - Reference Manual, 1770-6.5.16, October 1996 Allen-Bradley
Change Page(s)
Updated software name “Anybus Config Tool” to “Anybus Configuration Manager” -
Changed the number of possible transactions 32
Updated information about the trigger byte 37
Updated information about the CRC-algorithm 44
Updated frontpage information -
Updated sales and support page -
Updated System Requirements for Anybus Configuration Manager 13
Revision Date Author Chapter Description
2.00 2003-06-16 PeP All 2nd major release
2.50 2005-11-03 PeP All Major rewrite
2.51 2006-03-27 PeP All Minor updates & adjustments
2.52 2006-12-22 PeP All Misc. minor corrections
2.53 2008-02-08 PeP 1 Minor update
2.54 2009-04-24 KeL All Misc. minor corrections and updates
3.00 2011-02-08 KaD All Misc. minor corrections, new template and DF1 functionality
3.01 2011-09-30 KaD All Misc corrections and updates, new Anybus Configuration Manager
name

About This Document P-6
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Anybus Communicator for Modbus Plus
Doc.Rev. 3.01
Conventions & Terminology
The following conventions are used throughout this document:
• Numbered lists provide sequential steps
• Bulleted lists provide information, not procedural steps
• The term ‘user’ refers to the person or persons responsible for installing the Anybus Communi-
cator in a network.
• The term ‘ABC’ refers to the Anybus Communicator.
• Hexadecimal values are written in the format 0xNNNN, where NNNN is the hexadecimal value.
• Decimal values are represented as NNNN where NNNN is the decimal value
• As in all communication systems, the terms “input” and “output” can be ambiguous, because
their meaning depend on which end of the link is being referenced. The convention in this doc-
ument is that “input” and “output” are always being referenced to the master/scanner end of the
link.
Glossary
Term Meaning
ABC Anybus®Communicator™
Broadcaster A protocol-specific node in the configuration that handles transactions destined to all nodes.
MBP Modbus Plus
Command A predefined transaction.
Configuration List of configured nodes with transactions on the subnetwork.
Fieldbus The higher level network to which the communicator is connected.
Fieldbus Control System Fieldbus master
Frame Object Low level entities which are used to describe the different parts of a transaction.
Monitor A tool for debugging the Anybus Communicator and the network connections.
Node A device in the configuration which defines the communication with a node on the subnetwork
Subnetwork The network that is logically located on a subsidiary level with respect to the fieldbus, and to
which the Anybus Communicator acts as a gateway.
Transaction A generic building block that is used in the subnetwork configuration and defines the data that
is sent and received on the subnetwork.
User Person or persons responsible for installing the Anybus Communicator
Higher Level Network In this case, Modbus Plus
Network
Fieldbus

About This Document P-7
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Sales and Support
Sales Support
HMS Sweden (Head Office)
E-mail: s[email protected]e E-mail: [e-mail]
Phone: +46 (0) 35 - 17 29 56 Phone: +46 (0) 35 - 17 29 20
Fax: +46 (0) 35 - 17 29 09 Fax: +46 (0) 35 - 17 29 09
Online: www.anybus.com Online: www.anybus.com
HMS North America
E-mail: [e-mail] E-mail: [e-mail]
Phone: +1-312 - 829 - 0601 Phone: [phone]
Toll Free: +1-888-8-Anybus Toll Free: +1-888-8-Anybus
Fax: [phone] Fax: [phone]
Online: www.anybus.com Online: www.anybus.com
HMS Germany
E-mail: [e-mail] E-mail: [e-mail]
Phone: [phone] Phone: [phone]
Fax: [phone] Fax: [phone]
Online: www.anybus.de Online: www.anybus.de
HMS Japan
E-mail: [e-mail] E-mail: [e-mail]
Phone: [phone] Phone: [phone]
Fax: [phone] Fax: [phone]
Online: www.anybus.jp Online: www.anybus.jp
HMS China
E-mail: [e-mail] E-mail: [e-mail]
Phone: [phone] Phone: [phone]
Fax: [phone] Fax: [phone]
Online: www.anybus.cn Online: www.anybus.cn
HMS Italy
E-mail: [e-mail] E-mail: [e-mail]
Phone: [phone] Phone: [phone]
Fax: [phone] Fax: [phone]
Online: www.anybus.it Online: www.anybus.it
HMS France
E-mail: [e-mail] E-mail: [e-mail]
Phone: [phone] Phone: [phone]
Fax: [phone] Fax: [phone]
Online: www.anybus.fr Online: www.anybus.fr
HMS UK & Eire
E-mail: [e-mail] E-mail: [e-mail]
Phone: [phone] Phone: +46 (0) 35 - 17 29 20
Fax: [phone] Fax: +46 (0) 35 - 17 29 09
Online: www.anybus.co.uk Online: www.anybus.com
HMS Denmark
E-mail: i[email protected] E-mail: [e-mail]
Phone: [phone] Phone: +46 (0) 35 - 17 29 20
Fax: [phone] Fax: +46 (0) 35 - 17 29 09
Online: www.anybus.com Online: www.anybus.com
HMS India
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Phone: [phone] Phone: +46 (0) 35 - 17 29 20
Fax: [phone] Fax: +46 (0) 35 - 17 29 09
Online: www.anybus.com Online: www.anybus.com

Doc.Id. SCM-1200-093
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Chapter 1
1. About the Anybus Communicator Modbus Plus
The Anybus Communicator for Modbus Plus acts as a gateway between virtually any serial application
protocol and a Modbus Plus-based network. Integration of industrial devices is enabled without loss of
functionality, control and reliability, both when retro-fitting to existing equipment as well as when set-
ting up new installations.
Subnetwork
The gateway can address up to 31 nodes, and supports the following physical standards:
•RS-232
•RS-422
•RS-485
Modbus Plus Interface
Modbus Plus connectivity is provided through patented Anybus technology; a proven industrial com-
munication solution used all over the world by leading manufacturers of industrial automation products.
• Up to 32 words of global (cyclic I/O) data in each direction
• Supports Global Data Base Transaction
• Point-to-point parameter data (up to 125 words)
• Onboard Node ID and Source ID switches
• Galvanically isolated bus electronics
PC configuration
and monitoring
Modbus Master
(e.g a PLC)
Serial communication devices
INVERTER
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HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
Multi-drop up to 31 nodes
Multi-Node Serial Sub NetworkSingle-Node Serial Sub Network
PC configuration
and monitoring
Modbus Master
(e.g a PLC)
Serial communication
device
INVERTER
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HMI
HMI
HMI
HMI
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HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
HMI
(Modbus Plus Network)
(Modbus Plus Network)

About the Anybus Communicator Modbus Plus 9
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1.1 External View
For wiring and pin assignments, see “Connector Pin Assignments” on page 73.
A: Modbus Plus Connector
This connector is used to connect the gateway to the field-
bus.
See also...
- “Modbus Plus Connector” on page 73
B: Configuration Switches
See also...
- “Configuration Switches” on page 11
C: Status LEDs
See also...
- “Status LEDs” on page 10
D: PC-connector
This connector is used to connect the gateway to a PC for
configuration and monitoring purposes.
See also...
- “Hardware Installation” on page 12
- “PC Connector” on page 74
E: Sub-network Connector
This connector is used to connect the gateway to the serial subnetwork.
See also...
- “Hardware Installation” on page 12
- “Subnetwork Interface” on page 75
F: Power Connector
This connector is used to apply power to the gateway.
See also...
- “Hardware Installation” on page 12
- “Power Connector” on page 73
- “Technical Specification” on page 77
G: DIN-rail Connector
The DIN-rail mechanism connects the gateway to PE (Protective Earth).
See also...
- “Hardware Installation” on page 12
- “Technical Specification” on page 77
G
A
C
B
D
E
F

About the Anybus Communicator Modbus Plus 10
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1.2 Status LEDs
# State Status
1 - Error Off -
Red Communication error
2 - Active Off -
Flash every 160ms
Flash every 1s
2 flashes
3 flashes
4 flashes
- Normal operation
- MONITOR_OFFLINE state
- MAC_IDLE never-getting-token state
- Not detecting any other nodes
- Duplicate node ID detected
3 - (not used) - -
4 - Init Off -
Green Peer interface initialized
5 - Subnet Statusa
a. This led turns green when all transactions have been active at least once. This includes any
transactions using “change of state” or “change of state on trigger”. If a timeout occurs on a
transaction, this led will turn red.
Off Power off
Green, flashing Running correctly, but one or more transaction
error(s) have occurred
Green Running
Red Transaction error/timeout or subnet stopped
6 - Device Status Off Power off
Alternating Red/Green Invalid or missing configuration
Green Initializing
Green, flashing Running
Red Bootloader modeb
b. The gateway is in bootloader mode, and firmware must be restored in order for it to work
properly. Start up the Anybus Configuration Manager and connect to the Anybus Communi-
cator. Choose Tools/Options/ABC. Click “Factory Restore” to restore firmware. See “Tools”
on page 24.
Red, flashing If the Device Status LED is flashing in a sequence
starting with one or more red flashes, please note
the sequence pattern and contact the HMS support
department
1
3
5
2
4
6

About the Anybus Communicator Modbus Plus 11
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1.3 Configuration Switches
These switches are used to set the Modbus Plus node and source ID:s. Note that the
switches are read once during startup, i.e. any changes requires a reset in order to have
effect.
Normally, these switches are covered by a plastic hatch. When removing the hatch,
avoid touching the circuit boards and components inside.
The switches are interpreted as follows:
Switch A - Source ID
Switch B - Node ID
# sw. 1 sw. 2 sw. 3 sw. 4 sw. 5 sw. 6
1ONONONONONON
2ONONONONONOFF
3ONONONONOFFON
... ... ... ... ... ... ...
64 OFF OFF OFF OFF OFF OFF
# sw. 1 sw. 2 sw. 3 sw. 4 sw. 5 sw. 6
1ONONONONONON
2ONONONONONOFF
3ONONONONOFFON
... ... ... ... ... ... ...
64 OFF OFF OFF OFF OFF OFF
ON
123456
ON
123456
A
B

About the Anybus Communicator Modbus Plus 12
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1.4 Hardware Installation
Perform the following steps when physically installing the Anybus Communicator:
1. Snap the gateway on to the DIN-rail (See “DIN-rail Connector” on page 9)
The DIN-rail mechanism works as follows:
To snap the gateway on, first press it downwards (1) to compress the
spring in the DIN-rail mechanism, then push it against the DIN-rail as to
make it snap on (2)
To snap the gateway off, push it downwards (1) and pull it out from the
DIN-rail (2), as to make it snap off from the DIN-rail
2. Connect the gateway to the Modbus Plus network
3. Set the Modbus Plus Node ID and Source IDs as desired
4. Connect the gateway to the serial subnetwork
5. Connect the gateway to a free COM-port on the PC via the PC-cable
6. Connect the power cable and apply power
7. Start Anybus Configuration Manager on the PC
(Anybus Configuration Manager attempts to detect the serial port automatically. If not success-
ful, select the correct port manually in the “Port”-menu)
8. Configure the gateway using the Anybus Configuration Manager and download the
configuration
1
2
1
2

About the Anybus Communicator Modbus Plus 13
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1.5 Software Installation
1.5.1 Anybus Configuration Manager
System requirements
• Pentium 133 MHz or higher
• 650 MB of free space on the hard drive
•32MBRAM
• Screen resolution of 800x600 (16 bit color) or higher
• Microsoft Windows™ 2000 / XP / Vista / 7 (32 bit)
• Internet Explorer 4.01 SP1 or newer
Installation
• Anybus Communicator resource CD
Insert the CD and follow the onscreen instructions. If the installation does not start automatical-
ly, right-click on the CD-drive icon and select Explore. Execute ‘setup.exe’ and follow the on-
screen instructions.
• From website
Download and execute the self-extracting .exe-file from the HMS website (www.anybus.com).

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Chapter 2
2. Basic Operation
2.1 General
The Anybus Communicator is designed to exchange data between a serial subnetwork and a higher level
network. Unlike most other gateway devices of similar kind, it does not have a fixed protocol for the
subnetwork, and can be configured to handle almost any form of serial communication.
The gateway can issue serial telegrams cyclically, on change of state, or based on trigger events issued by
the control system of the higher level network (i.e. the fieldbus master or PLC). It can also monitor cer-
tain aspects of the subnetwork communication and notify the higher level network when data has
changed.
An essential part of the Anybus Communicator package is the Anybus Configuration Manager, a Win-
dows™ application which is used to supply the gateway with a description of the subnetwork protocol.
No programming skills are required; instead, a visual protocol description-system is used to specify the
different parts of the serial communication.

Basic Operation 15
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2.2 Data Exchange Model
Internally, the data exchanged on the subnetwork, and
the data exchanged on the higher level network, resides
in the same memory.
This means that in order to exchange data with the sub-
network, the higher level network simply reads and
writes data to memory locations specified using the An-
ybus Configuration Manager. The very same memory
locations can then be exchanged on the subnetwork.
The internal memory buffer is divided into three areas
based on their function:
• Input Data (512 bytes)
This area can be read by the higher level net-
work.
(how this data is represented on the higher level
network will be described later in this chapter).
• Output Data (512 bytes)
This area can be written to by the higher level
network.
(how this data is represented on the higher level
network will be described later in this chapter).
• General Data
This area cannot be accessed from the higher level network, but can be used for transfers be-
tween individual nodes on the subnetwork, or as a general “scratch pad” for data. The actual size
of this area depends on the amount of data that is exchanged on the subnetwork. The gateway
can handle up to 1024 bytes of General Data.
2.2.1 Memory Map
When building the subnetwork configuration using the Anybus Configuration Manager, the different ar-
eas described above are mapped to the memory locations (addresses) specified below.
General Data
Internal Memory
Input Data
(512 bytes)
Subnetwork
Output Data
(512 bytes)
Higher Level Network
Input Data Output Data General Data
Subnetwork: Subnetwork: Subnetwork:
Fieldbus:
Read/Write
Read Only
Read Only
Read/Write
Read/Write
-Fieldbus: Fieldbus:
0x000 0x200
0x1FF 0x3FF
0x400
0x???

Basic Operation 16
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2.2.2 Data Exchange Example
In the following example, a temperature regulator on the subnetwork exchanges information with a PLC
on the higher level network, via the internal memory buffers in the gateway.
The Temperature Regulator has two
registers, holding the Setpoint Temperature
and the Actual Temperature respectively.
The PLC exchange data between the internal
PLC memory and the slaves (in this case the
gateway) on the Modbus Plus network.
The gatewaycopies the Output Register
of the Temperature Regulator to the
Input Data area.
The gateway copies the Temperature-
Setpoint from the Output Data area to
the Input Register in the Temperature-
Regulator.
The PLC Memory associated with
the gateway is exchanged;
Data from the Input Data area is copied to
PLC Input Memory, and PLC Output
Memory is copied to the Output Data
area.
Input Data
Anybus Communicator Gateway
Serial Device - Temperature Regulator
PLC (Modbus Plus Master)
Output Data General Data
0x000 0x200
0x1FF 0x3FF
0x400
0x???
Output Register Input Register
Temperature Setpoint
Temperature Setpoint
Actual Temperature
Actual Temperature
PLC Memory (Inputs) PLC Memory (Outputs)
Temperature Setpoint
Actual Temperature
(not used in this example)
Modbus PlusSubnetwork

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2.3 Subnetwork Protocol
2.3.1 Protocol Modes
The gateway features three distinct modes of operation regarding the subnetwork communication, called
‘Master Mode’, ‘DF1 Master Mode’ and ‘Generic Data Mode’. Note that the protocol mode only spec-
ifies the basic communication model, not the actual subnetwork protocol.
•MasterMode
In this mode, the gateway acts as a master on the subnetwork, and the serial communication takes
place in a query-response fashion. The nodes on the network are not permitted to issue messages
unless they have been addressed by the gateway first.
For more information about this mode, see “Master Mode” on page 18.
• DF1 Master Mode
In this mode, the gateway acts as a master on the subnetwork, using the DF1 protocol. The serial
communication takes place in a query-response fashion. For information about this mode see
“DF1 Protocol Mode” on page 51.
• Generic Data Mode
In this mode, there is no master-slave relationship between the subnetwork nodes and the gate-
way; any node on the subnetwork, including the gateway, may spontaneously produce or con-
sume messages.
For more information about this mode, see “Generic Data Mode” on page 19.
2.3.2 Protocol Building Blocks
The following building blocks are used in Anybus Configuration Manager to describe the subnetwork
communication. How these blocks apply to the three protocol modes will be described later in this doc-
ument.
•Node
A node represents a single device on the subnetwork. Each node can be associated with a
number of transactions, see below.
•Transaction
A ‘transaction’ represents a complete serial telegram, and consists of a number of frame objects
(see below). Each transaction is associated with a set of parameters controlling how and when to
use it on the subnetwork.
• Commands
A ‘command’ is simply a predefined transaction stored in a list in the Anybus Configuration Man-
ager. This simplifies common operations by allowing transactions to be stored and reused.
• Frame Object
‘Frame objects’ are low level entities used to compose a transaction (see above). A frame object
can represent a fixed value (a constant), a range of values (limit objects), a block of data or a cal-
culated checksum.

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2.3.3 Master Mode
In this mode, the communication is based on a query-response scheme; when the gateway issues a query
on the subnetwork, the addressed node is expected to issue a response to that query. Nodes are not per-
mitted to issue responses spontaneously, i.e. without first receiving a query.
There is one exception to this rule; the broadcaster. Most protocols offer some way of broadcasting mes-
sages to all nodes on the network, without expecting them to respond to the broadcasted message. This
is also reflected in the gateway, which features a dedicated broadcaster node.
In Master Mode, Anybus Configuration Manager comes preloaded with most commonly used Modbus
RTU commands, which can conveniently be reached by right-clicking on a node in the Anybus Config-
uration Manager and selecting ‘Insert New Command’. Note however that this does not in any way pre-
vent other protocols based on the same query-response message-scheme to be implemented.
Subnetwork Devices
Gateway
Control System