Hello,
last week I bought a M203. I would like to read the digital inputs with the MODBUS protocol. I tried to use the neuron_tcp_modbus_server with libmodbus but the results are wrong, they change at every reading. Here my code:

    mb = modbus_new_tcp("192.1681.1.102", 502);
    //modbus_set_slave(mb, 2);
    modbus_connect(mb);

    /* Read 16  bit sfrom the address 0 */
    modbus_read_bits(mb, 0, 16, tab_reg);
  
    modbus_close(mb);
    modbus_free(mb);
    for (int i = 0; i < 16; i++) {
    std::cout << static_cast<uint8_t>(tab_reg[i]) << std::flush;
    std::cout <<",";
    }

Any suggestions?
Thanks.