Basics, Modbus TCP technology | Schneider Electric LXM32M manual

LXM32M	3 Basics

3 Basics

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3.1Modbus TCP technology

3.1.1Function principle

Modbus TCP is an Ethernet fieldbus. Modbus TCP describes the transmission of the Modbus protocol via the Ethernet interface and the TCP/IP transport and network layers.

The Modbus TCP client (master) connects to the Modbus TCP server (slave). Once the connection is established, the client sends Modbus requests to the server. These requests are processed by the server.

The result is returned to the client as a Modbus response.

The Modbus TCP services are identical to the Modbus RTU services.

3.1.2Bus topology

Star and tree topologies can be used. It is possible to use hubs or switches. In the case of high bus loads with many devices, it is recom- mended to use a switches.

The maximum length of a segment is 100 m. A segment consists of devices and hubs. A network can be subdivided into several segments by means of gateways or switches. Short cables and a star topology are recommended to achieve a fast bus cycle.

The transmission rate is 10 or 100 MBit/s in half-duplex mode. If switches are used, transmission is also possible in full duplex mode.

0198441113843, V1.01, 01.2012

Modbus-TCP module

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Schneider Electric LXM32M manual Basics, Modbus TCP technology, Function principle, Bus topology

Contents

LXM32M Important information Table of contents Diagnostics and troubleshooting Accessories and spare parts LXM32M About this manual Further reading Fieldbus products on the network Introduction LXM32M Before you begin safety information Qualification of personnelIntended use Hazard categories Basic information Standards and terminology Bus topology BasicsModbus TCP technology Function principle Client / server model Network service Snmp Structure of a Modbus message Modbus TCP protocol Field Length Description Mbap header Connection management Modbus TCP communication Excep Name Description Tion Code Modbus response to a Modbus request Address Value Reading and writing parameters 4 I/O scanning to Drive Profile Lexium Byte Meaning Data type Parameter address 4.1 I/O scanning Output Bit Meaning 4.2 I/O scanning Input Inputs Bit Signal Factory setting Parameter channel Ctrl Subindex Index Modbus services Function Code Function Code 3 Read Multiple RegistersField Bytes Value Meaning Sub-function Code Diagnostics function Function Code 8 Diagnostics Function Code 16 Write Multiple Registers Function Code 23 ReadWrite Multiple Registers Object ID Object name Value Function Code 43 Encapsulated Interface Transport Example of Function Code Examples LXM32M Installation Installation of the moduleDescription Order no Pin Signal Meaning Electrical installation Commissioning the device Commissioning Switching on the device Power stage supply is switched off First Setup Dhcp / dhcP Dhcp Bootp / boot BootpManual assignment of the network address Manual / MAnu Manual IP address Ethernet module, byte Assignment of the network address via Bootp Assignment of the network address via Dhcp Setting the protocol Setting the transmission rate Set the IP address of the gateway with the parameters Setting the gateway Master with Word Swap Setting I/O-Scanning Setting the master for I/O scanningActivating I/O scanning Setting the mapping for I/O scanning PLC Setting communication monitoring for I/O scanning Setting the web server 0198441113843, V1.01 Operation Operating states Indication of the operating stateBit Name Meaning Bit Name Meaning Operating state Changing the operating state Indicating and monitoring the operating mode Operating modesBit Name Description Bit Name Description Starting and changing an operating mode MODE+ACTION Overview of operating modes Operating mode Jog Operating mode Electronic Gear 24 h Operating mode Profile Torque 23 h Operating mode Profile Velocity Operating mode Profile Position Operating mode Homing LXM32M6 Operation Operating mode Motion Sequence Web server Extended settings User interface Main menu Submenu Content FTP server Accessing the FTP server FDR service Fast Device Replacement LXM32M Fieldbus communication error diagnostics Diagnostics and troubleshooting Color Status Meaning Status LEDs Meaning for EtherNet/IP Meaning for Modbus TCP Color Error indication Excep Name Description Tion Code LXM32M Cables Accessories and spare parts LXM32M Units and conversion tables Glossary Moment of inertia TemperatureRotation Torque Terms and Abbreviations LXM32M Index LXM32M