Arduino Slave Modbus RTU & PLC Panasonic RS232 Industrial : 4 Steps

In this new test we will use an Arduino Mega 2560 board and a Panasonic FPX PLC, in this case we will configure the PLC as a Modbus RTU master and the Arduino as a Modbus RTU slave via RS232. We will use as a base previous examples of both platforms.

Since arduino handles TTL voltages 0 -5v we have manufactured a MAX232 TTL to RS232 converter, quick view of MAX232 DIY board, We have taken 5v to power the MAX232, although we recommend using an external 5v source and unify ground.

More info and downloads

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Step 1: Components and Materials Required for Testing

Components and materials required for testing

1- Arduino Mega 2560 R3

1- Converter TTL to RS232

1-PLC Panasonic FPX C14R

1-Wires

Step 2:

Step 3: Arduino Mega 2560 Slave Modbus RTU & PLC Panasonic Master (RS232)

Arduino Mega 2560 Slave Modbus RTU & PLC Panasonic Master (RS232)

Conclusions

Although for some this test is similar to previous tests, visual and functionally does not vary, but internally the library and / or the configuration as master or slave are different would be denoted by revolving the Master and Slave Modbus libraries for Arduino.
The board of Arduino controls without any inconvenience the PLC, you only have to consider communication parameters, speeds physical connections, wiring, etc.

Easily this application, in this case a PLC in more practical cases data solutions or control with meters, counters and PID controllers.

We recommend not to use speeds higher than 9600, if it works at 115200 but we want to guarantee security in the transmission given the Arduino and max232.