Operation in RTU CANopen Network - Master Mode
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NOTE!
The RS485 interface is available on the PLC200 model only.
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In addition to operating as a slave, the programmable controller PLC200 also allows operation as master of the Modbus RTU CANopen network. For this operation, it is necessary to observe the following points:
| • | Only the RS485 interface allows operation as a network master. |
| • | In the product settings, the operating mode must be defined as "Master", in addition to the baud rate, parity and stop bits, which must be the same for all devices on the network. |
| • | The Modbus RTU network master has no address, thus the address configured in the PLC200 is not used. |
| • | The sending and receiving of telegrams via RS485 interface using the Modbus RTU protocol is programmed with blocks in Ladder programming language. It is necessary to know the available blocks and the software Ladder programming software to be able to program the network master. |
| • | The following functions are available to send requests via Modbus master: |
| 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 Programming the master
In order to control and monitor Modbus RTU communication using the programmable controller PLC200, the following blocks were developed, which must be used during the Ladder programming.
