Java通过jlibmodbus 库实现的Modbus TCP协议取值-优快云博客

文章详细描述了如何在Java中使用jlibmodbus库连接到ModbusTCP设备，执行读取线圈、离散输入、输入寄存器和保持寄存器的操作，并指出jlibmodbus在处理deviceid=0时可能出现的问题。

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pom

<dependency>
    <groupId>com.intelligt.modbus</groupId>
    <artifactId>jlibmodbus</artifactId>
    <version>1.2.9.9</version>
</dependency>

代码

    public static void main(String[] args) throws ModbusProtocolException, ModbusNumberException, ModbusIOException {
        TcpParameters tcpParameters = new TcpParameters();
        try {
            tcpParameters.setHost(InetAddress.getByName("127.0.0.1"));
        } catch (UnknownHostException e) {
            throw new RuntimeException(e);
        }
        tcpParameters.setKeepAlive(true);
        tcpParameters.setPort(505);
        ModbusMaster modbusMasterTCP = ModbusMasterFactory.createModbusMasterTCP(tcpParameters);
        Modbus.setAutoIncrementTransactionId(true);
        boolean[] coils = modbusMasterTCP.readCoils(1, 0, 8);
        for (boolean b : coils) {
            System.out.println("线圈"+b);
        }

        boolean[] discreteInputs = modbusMasterTCP.readDiscreteInputs(1, 0, 8);
        for (boolean b : discreteInputs) {
            System.out.println("离散"+b);
        }

        int[] inputRegisters = modbusMasterTCP.readInputRegisters(1, 0, 2);//输入
        for (int anInt : inputRegisters) {
            System.out.println("输入"+anInt);
        }

        int[] holdingRegisters = modbusMasterTCP.readHoldingRegisters(1, 0, 2);//保持
        for (int anInt : holdingRegisters) {
            System.out.println("保持"+anInt);
        }
        
    }

线圈true
线圈false
线圈false
线圈false
线圈false
线圈false
线圈true
线圈false
离散false
离散true
离散false
离散false
离散false
离散false
离散true
离散false
输入1
输入2
保持0
保持17402

用这个需要注意 jlibmodbus 好像不能取值 device id = 0的没深入研究

final static public int BROADCAST_ID = 0x00;


 synchronized public ModbusResponse processRequest(ModbusRequest request) throws ModbusProtocolException, ModbusIOException {
        try {
            sendRequest(request);
            if (request.getServerAddress() != Modbus.BROADCAST_ID) {
                do {
                    try {
                        ModbusResponse msg = (ModbusResponse) readResponse(request);
                        request.validateResponse(msg);
                        /*
                         * if you have received an ACKNOWLEDGE,
                         * it means that operation is in processing and you should be waiting for the answer
                         */
                        if (msg.getModbusExceptionCode() != ModbusExceptionCode.ACKNOWLEDGE) {
                            if (msg.isException())
                                throw new ModbusProtocolException(msg.getModbusExceptionCode());
                            return msg;
                        }
                    } catch (ModbusNumberException mne) {
                        Modbus.log().warning(mne.getLocalizedMessage());
                    }
                } while (TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - requestTimeNs) < getConnection().getReadTimeout());
                /*
                 * throw an exception if there is a response timeout
                 */
                throw new ModbusIOException("Response timeout.");
            } else {
            /*
             return because slaves do not respond broadcast requests

            返回无效的

             */
                broadcastResponse.setFunction(request.getFunction());
                return broadcastResponse;
            }
        } catch (ModbusIOException mioe) {
            disconnect();
            throw mioe;
        }
    }