On this occasion I made our arduino communication with HMI Panasonic GT01 monochrome display via RS232 Modbus RTU, Arduino screen as Master and slave.
1. The value of the ADC 0 of arduino from a potentiometer 100 k will be displayed on the HMI Panasonic
2. value entered from a numeric keypad from the HMI was displayed from the arduino oled screen.
Blog PDAControl English
Step 1: Conections and Arquitecture
one Max232 is required for physical comunicaion between Arduino and the Panasonic screen.
OLED display for debugging and visualization features data is used from Arduino.
Components and materials required for testing
1 HMI GT01 Panasonic
Step 2: GTWIN Panasonic
The Panasonic GT01 screen is programmed into the software GTWIN
records follows redirected
GDT0 = Holding Register 
GDT1 = Holding Register 
Step 3: Final Test
Arduino is configured for reading and writing 10 log 10 records.