This time I have communicated the Arduino with Panasonic PLC and I checked the Arduino useful in the industrial field direfencia of the previous tutorials I've tested both devices communicating via RS - 232.
1. The arduino sent via modbus ADC value 0 to Holding Register 0 and the plc into a strategy compared as follows 1- If ADC Arduino> 500 relay output PLC = 1 2 else PLC relay output = 0
2. The PLC send the value 2 of its potentiometers from 0 to 1000 and displayed on the display arduino Oled the respective values
Step 1: PLC Panasonic FPX C14R
Programmable Logic Controller used in industrial in this case the family FPX panasonic (Aromat - Nais)
This PLC has Modbus RTU protocol as master and slave To configure a teacher must create a strategy, if set as slave does not require code as the default plc is a slave and records are automatically routed.
DT0 = Holding Register 
DT1 = Holding Register 
The control strategy of these PLC is done in the software FPWIN Pro
Step 2: Code Arduino Y MAX232
The arduino is configured as RTU Master to read 10 and write 10 Holding Registers y conection MAX232
Components and materials required for testing
1 Controller PLC Panasonic FPX X14R