ImodbusRTUmasterAdd() registers a Master request for repeated execution.

bool ImodbusRTUmasterAdd(HardwareSerial& serialPort, uint8_t slaveId, uint8_t functionCode, uint16_t address, uint16_t quantity, uint16_t* data, uint16_t timeoutMs = 100)

void setup() {
  ImodbusRTUmasterInit(Serial2, 9600);  // Set the Master's communication port and baud rate.
  ImodbusRTUmasterAdd(Serial2, 1, 0x03, 0x00, 1, &D[1]);  // Register a Master request for repeated execution.
  ImodbusRTUmasterAdd(Serial2, 1, 0x03, 0x01, 1, &D[2]);  // Register a Master request for repeated execution.
}
 
void loop() {
  ImodbusRTUmasterRun();  // Execute registered requests or the specified single request.
}

• Keep calling the Slave or Master execution function in loop().
• The data array size must be at least the requested quantity.
• Do not treat return codes BUSY and IDLE as communication failures.
• When sharing M and D with Cnet/MC Protocol, define a single final size and initialization order. Do not call ImodbusRTUMem() or ICnetMem() again at runtime.
• Memory allocation functions do not return success status. For nonzero sizes, verify that M and D are not nullptr before accessing them in user code.

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