Panasonic FP0H Series User Manual

Also see for FP0H Series: User manual User manual User manual User manual Quick start guide

1.2.3 MODBUS RTU Master / Slave Communication■ Overview of function● Used for communication with other devices that support the MODBUS RTU protocol.● Master communication is performed when the master unit sends commands to slave units,and the slave unit returns responses (response messages) according to the instructions.Data can be read and written between PLC and external devices by specifying unit numbersand memory addresses and executing F145 (SEND) / F146 (RECV) instructions in a userprogram, because PLC automatically creates messages according to the protocol.● A higher device connected to PLC has the transmission right in slave communication. Slavecommunication is performed when the device sends a command, and PLC returns aresponse. In slave communication, no communication program is required on the PLC side,because PLC automatically returns a response.● The data size that can be sent or received at a time is a maximum of 127 words for registertransmission, and 2,040 bits for bit transmission.Master functionPLCRS-485MasterSlave Slave SlaveDevices thatsupportModbus RTUslave functionDevices thatsupportModbus RTUslave functionDevices thatsupportModbus RTUslave functionSlave functionPLC PLC PLCRS-485Slave Slave SlaveMasterDevices thatsupportModbus RTU■ Purpose of MODBUS-RTU master communication (example)Used for connection with devices that support the MODBUS-RTU protocol.● Temperature regulator KT series● Devices that support MODBUS-RTU from other manufacturers■ Purpose of MODBUS-RTU slave communication (example)Used for access from a higher device using MODBUS-RTU commands.1.2 Overview of Communication Functions1-6 WUME-FP0HCOM-06