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Overview of the Modbus TCP |
  
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Overview of the Modbus TCP |
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Operation in Modbus TCP Network – Client Mode
Besides the operation as server, the programmable controller PLC200 also allows the operation as client of the Modbus TCP network. For this operation, it is necessary to observe the following points:
| • | The sending and receiving of telegrams via Ethernet interface using the Modbus TCP protocol is programmed by using blocks in Ladder programming language. It is necessary to know the available blocks and the software of Ladder programming to be able to program the network master. |
| • | The following functions are available to send requests by the Modbus TCP client: |
| o | Function 01: Read Coils |
| o | Function 02: Read Discrete Inputs |
| o | Function 03: Read Holding Registers |
| o | Function 04: Read Input Registers |
| o | Function 05: Write Single Coil |
| o | Function 06: Write Single Register |
| o | Function 15: Write Multiple Coils |
| o | Function 16: Write Multiple Registers |
Blocks for the Programming of the Client
In order to control and monitor Modbus TCP communication using the programmable controller PLC200, the following blocks were developed, which must be used during Ladder programming.