Modicon M580 Plc Page 3-10 Communication

3/10 Modicon M580 automation platform PlantStruxure Ethernet architectures Industrial Ethernet communication services Functions (continued) Modbus standard communication protocol Modbus, the industry communication standard since 1979, has been combined with Ethernet Modbus/TCP, the medium for the Internet revolution, to form Modbus/TCP, a completely open Ethernet protocol. The development of a connection to Modbus/ TCP does not require any proprietary component, nor purchase of a license. This protocol can easily be combined with any product supporting a standard TCP/IP communication stack. The specifications can be obtained free of charge from the following website: . Modbus/TCP, simple and open The Modbus application layer is very simple and universally familiar with its 9 million installed connections. Thousands of manufacturers have already implemented this protocol. Many have already developed a Modbus/TCP connection and numerous products are currently available. The simplicity of Modbus/TCP enables any field device, such as an I/O module, to communicate on Ethernet without the need for a powerful microprocessor or a lot of internal memory. Modbus/TCP, high-performance Due to the simplicity of its protocol and the fast speed of 100 Mbps Ethernet, the performance of Modbus/TCP is excellent. This allows this type of network to be used in real-time applications such as I/O scanning. Modbus/TCP, a standard The application protocol is identical on Modbus serial link, Modbus Plus, or Modbus/ TCP. This means that messages can be routed from one network to the other without converting protocol. Since Modbus is implemented on top of the TCP/IP layer, users can also benefit from IP routing enabling devices located anywhere in the world to communicate without worrying about the distance between them. Schneider Electric offers a complete range of gateways for interconnecting a Modbus/TCP network to existing Modbus Plus or Modbus serial link networks. The IANA organization (Internet Assigned Numbers Authority) has allocated the fixed port TCP 502 (well-known port) to the Modbus protocol. Thus Modbus has become an Internet standard. Modbus and Modbus/TCP are recognized by the IEC/EN 61158 international standard as a fieldbus. They are also compliant with the Chinese National Standard managed by ITEI. Interfacing CANopen with Modbus/TCP CiA DSP 309-2 provides standardized mapping of CANopen data for transport on Ethernet Modbus/TCP networks. The specification reserves Modbus function code 43/13 for this purpose. This function code is reserved exclusively for CANopen. Modbus TCP/IP characteristics Maximum size of data: b Read: 125 words or registers b Write: 100 words or registers Functions (continued) Modbus/TCP function codes dec hex Bit access Read n input bits 02 02 Read n output bits 01 01 Read exception status 07 07 Write 1 output bit 05 05 Write n output bits 15 0F Read 1 input word 04 04 Read n input words 03 03 Write 1 output word 06 06 Write n output words 16 10 Read device ID 43/14 2B/0E Examples of Modbus/TCP function codes for accessing data and diagnostics Processors: page 1/20 I/O architectures: page 2/2 Ruggedized Modicon M580 modules: page 4/2 2 1 3 4 5 6 7 8 9 10 2 1 3 4 5 6 7 8 9 10

Previous Page
Next Page