Modbus Rtu Communication; Overview Of Functions; About Modbus Rtu; Master Function - Panasonic FP0R User Manual

7.7 MODBUS RTU Communication

7.7.1 Overview of Functions

The MODBUS RTU protocol enables the communication between the FP0R and other devices
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(including our FP-X, FP-e, Programmable display GT series, KT temperature control unit and MODBUS
device made by other companies).
Enables to have conversations if the master unit sends instructions (command messages) to slave
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units and the slave units respond (response messages) according to the instructions.
Enables the communication between the devices of max. 99 units as the master function and slave
-
function is equipped.

About MODBUS RTU

The MODBUS RTU communication is a function for the master unit to read and write the data in slave
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units communicating between them.
There are ASCII mode and RTU (binary) mode in the MODBUS protocol, however, the FP0R is
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supported with the RTU (binary) mode only.

Master function

Writing and reading data for various slaves is available using the F145 (SEND) and F146 (RECV)
instructions.
Individual access to each slave and the global transmission is possible.
Use Type II instructions of F145 and F146 (Type directly specifying MODBUS address) to
communication with MODBUS devices made by other companies.
Slave function
If the slave units receive a command message from the master unit, they send back the response
message corresponding to the content.
Do not execute the F145 (SEND) or F146 (RECV) instructions when the unit is used as a slave unit.
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