HeidelbergInterface

HeidelbergInterface is a universal Arduino library for communication with the Heidelberg Wallbox Energy Control via RS485/Modbus-RTU. It is designed to work with eps8266/esp32. Additional hardware for the RS485 communication is required, e.g. MAX485 IC (cheap Dev-Boards available).

Minimal example

// HeidelbergInterface
// MIT License Copyright (c) 2023 F. Bisinger

#include <HeidelbergInterface.h>
#include <SoftwareSerial.h>

#define MODBUS_RATE_HEIDELBERG 19200  // Baud Rate
#define MAX485_DE 33                  // GPIO33, DE pin on the TTL to RS485 converter
#define MAX485_RX 34                  // GPIO34, RO pin on the TTL to RS485 converter
#define MAX485_TX 17                  // GPIO17, DI pin on the TTL to RS485 converter
#define SLAVE_ID_HEIDELBERG 1            // Configured slave ID of Heidelberg Wallbox

// Serial communication to the RS485 converter via SoftwareSerial
// Harware Serial will work fine as well
SoftwareSerial *serial;
HeidelbergInterface interface;

void setup()
{
  Serial.begin(115200);
  serial = new SoftwareSerial(MAX485_RX, MAX485_TX, false); //RX, TX
  // Wallbox Heidelberg Energy Control uses 19.200 bit/sec, 
  // 8 data bit, 1 parity bit (even), 1 stop bit
  serial->begin(MODBUS_RATE_HEIDELBERG, SWSERIAL_8E1);
  interface.begin(*serial, SLAVE_ID_HEIDELBERG, MAX485_DE); 
}

void loop()
{
  // must be called to keep the modbus data buffer updated 
  interface.mbloop();
  
  Serial.print("Heidelberg Wallbox Modbus Register Layout-Version: ");
  Serial.println(interface.getRegLayoutVersion(), HEX);
  /*
  FOR ALL AVAILABLE FUNCTIONS, SEE src/HeidelbergInterface.h
  */

  delay(5000);
}

Other RS485/Modbus Clients on the same bus

If you are working with different Modbus clients, especially with different communication speed or transmit configurations on the same hardwired bus, only one client/server configuration can be active at the same time. Therefor the library supports enabling or disabling the entire Modbus communication with disableCom() which stops polling of data from the registers and blocks any data being sent to the client. To reactivate communication simply call enableCom().

Development ToDos

• Basic WB communication
• Allow other RS485/Modbus devices on the same bus
• Multiple WB clients support

Dependencies

• EspSoftwareSerial
• ModbusMaster

Notice

All functions rely on Modbus register layout versions >= V1.0.8 if you are using older versions some function, e.g. remote lock will not work properly! You can retrieve your reg layout version with getRegLayoutVersion(). To see what features might be supported for your version have a look at the official datasheet.

🇩🇪 © F.Bisinger 2023