ImodbusRTUMem() sets the sizes of M and D memory used by the Slave.

void ImodbusRTUMem(uint16_t m_size, uint16_t d_size)

void setup() {
  ImodbusRTUMem(100, 200);  // Set the M·D memory sizes used by the Slave.
  ImodbusRTUAdr(0, 0);  // Set the start addresses of M·D memory.
  ImodbusRTUInit(Serial1, 1, 115200);  // Set the communication port, station number and baud rate.
}
 
void loop() {
  ImodbusRTU();  // Check incoming requests and process Slave responses.
  D[0] = 100;
  D[3] = 200;
}

• 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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