I am looking to make the communication between a CVW300 using Modbus RTU RS438 protocol with Android and I'm using the modbus4j library, but whenever I try to initialize "master.init ();" error.

            ModbusFactory factory = new ModbusFactory();
            SerialParameters params = new SerialParameters();

            params.setBaudRate(19200);
            params.setDataBits(8);

            params.setCommPortId("/dev/ttyS2");
            params.setStopBits(1);
            params.setParity(1);
            //params.setPortOwnerName();
            ModbusMaster master = factory.createRtuMaster(params);
            master.setTimeout(500);
            master.setRetries(0);

            try {
                master.init();
                master.getValue(1, RegisterRange.HOLDING_REGISTER, 0, DataType.FOUR_BYTE_FLOAT);

            } catch (ModbusTransportException e) {
                addStatus("1: " + e.getMessage().toString());
                e.printStackTrace();
            } catch (ErrorResponseException e) {
                addStatus("2: " + e.getMessage().toString());
                e.printStackTrace();
            } catch (ModbusInitException e) {
                addStatus("3: " + e.getMessage().toString());
                e.printStackTrace();
            } finally {
                master.destroy();
            }