RS485-UART-EchoTest

Version: 1.0 Date: 2020-12-21

This sketch is useful for debugging and testing RS485/UART wirings. Often the remote device is mounted somewhere on a rooftop or another inconvenient place. That's where this tool comes in and offers you a simulation for your lab.

It was intentionally made for the wind direction sensor: https://github.com/AndreasExner/iobroker-IoT-WindSensor

But it can be used for different purposes as well.

Configuration

#define SERIAL_BAUD_RATE 9600 //baud rate for RS485
#define DEBUG_BAUD_RATE 115200 //baud rate for FT232 / serial1

int counter=0;
bool debug = true;


byte windSensorFrame[] = {0x01, 0x03, 0x04, 0x00, 0x5A, 0x00, 0x00, 0x00, 0x00}; // default answer frame for the wind sensor DO NOT CHANGE
byte customFrame[] = {0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}; // your custom answer frame (CRC will be calculated automatically)

bool useWindSensorFrame = true; // echos a random wind direction if true, a custom frame or a copy of the incoming frame if false
bool useCustomFrame = false; // echos the custom frame if true, a copy of the incoming frame if false 

int expectedFrameSize = 8; // expected RX frame size

Do not activate useWindSensorFrame and useCustomFrame at the same time or the code will fail! Deactivate both to echo the RX frame back to the sender.

Tested environment

• Software
  • Arduino IDE 1.8.13 (Windows)
  • EspSoftwareSerial 6.10.0 plerup/espsoftwareserial: Implementation of the Arduino software serial for ESP8266 (github.com)
• Hardware
  • NodeMCU Lolin V3 (ESP8266MOD 12-F)
  • NodeMCU D1 Mini (ESP8266MOD 12-F)
  • 5 V MAX485 / RS485 Modul TTL to RS-485 MCU
  • FT232 Module

Wiring