ImodbusRTUmasterRun() executes a registered request or the specified single request.

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

void loop() {
  uint8_t state = ImodbusRTUmasterRun();
  if (state != IMODBUS_RTU_SUCCESS &&
      state != IMODBUS_RTU_BUSY &&
      state != IMODBUS_RTU_IDLE) {
    debugln(state, HEX);
  }
}

• 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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