Android plc通信

Posted 2023-02-19 LZ涸泽而渔

android/信捷plc modbus-ASCII串口通信

• modbus协议封装
• 串口通信
• 通信队列

终于有时间总结一下用到的技术了，之前忙得狗血淋头，搞这个plc弄到自闭，由于没有百度到任何案例，遂自己花大量的精力给弄出来并应用到运营项目中，给予各位参考

modbus协议封装

modbus是一种通讯规约，简单的来说，由起始符、帧头、寄存器命令、LRC校验、结束符等组成，此文中，modbus主要用于和信捷plc通讯，采用ascll编码方式（RTU类似，自行修改代码中转码部分即可），另外，因为是规约，所以得需要与你的上位机PLC一起对接，例如本文中规约为：寄存器地址长度为4-“0001”,通讯命令长度为1-“1”,意味着，像寄存器0001发送数据1，来完成对应的操作。
modbus封装类：

public class PlcModBusUtil 
    //起始符
    private final String START = "3A";
    //帧头
    private final String FRAME_HEADER = "3032";
    //写多个寄存器命令
    private final String WRITE_COMMAND = "3130";
    //写单个寄存器
    private final String WRITE_SIGNLE_COMMAND = "3036";
    //读命令
    private final String READ_COMMAND = "3033";
    //结束符
    private final String END = "0D0A";

    public static final String TAG = "PlcModBusUtil";

    /**
     * 封装modbus，写请求协议
     *
     * @return
     */
    public String getWriteString(String address, String[] data) 
        StringBuilder stringBuilder = new StringBuilder();
        //起始符
        stringBuilder.append(START);
        //帧头
        stringBuilder.append(FRAME_HEADER);
        //功能码
        if (data.length > 1) 
            stringBuilder.append(WRITE_COMMAND);
         else 
            stringBuilder.append(WRITE_SIGNLE_COMMAND);
        


        //地址,多个地址，只传起始地址，16进制转ascii
        stringBuilder.append(hexToAscii(address));

        //多个地址与数据，需要添加长度和位数
        if (data.length>1)
            //长度,例如：写2条数据，长度为2，位数为4，长度补足4位，位数补足2位
            StringBuilder lengthBuilder = new StringBuilder();
            lengthBuilder.append(data.length);
            int length = lengthBuilder.length();
            for (int i = 0; i < 4 - length; i++) 
                lengthBuilder.insert(0, "0");
            
            //转ascii
            stringBuilder.append(hexToAscii(lengthBuilder.toString()));

            //位数
            StringBuilder digitsBuilder = new StringBuilder();
            digitsBuilder.append(data.length * 2);
            int digitsLength = digitsBuilder.length();
            for (int i = 0; i < 2 - digitsLength; i++) 
                digitsBuilder.insert(0, "0");
            
            //转ascii
            stringBuilder.append(hexToAscii(digitsBuilder.toString()));
        

        //写入数据处理
        for (String datum : data) 
            //10进制转16进制
            StringBuilder hexString = new StringBuilder();
            hexString.append(datum);
            int hexLength = hexString.length();
            //转化后的16进制进行补位，目标为4位
            for (int i = 0; i < 4 - hexLength; i++) 
                hexString.insert(0, "0");
            
            //转ascii，添加数据
            stringBuilder.append(hexToAscii(hexString.toString()));
        

        //LRC校验结果生成，去掉起始
        stringBuilder.append(getLrc(stringBuilder.substring(START.length())));
        //添加结束符
        stringBuilder.append(END);
        return stringBuilder.toString();
    

    public String getReadString(String[] address) 
        StringBuilder stringBuilder = new StringBuilder();
        //起始符
        stringBuilder.append(START);
        //帧头
        stringBuilder.append(FRAME_HEADER);
        //读命令
        stringBuilder.append(READ_COMMAND);
        //地址，多个地址，只传起始地址,16进制转ascii
        stringBuilder.append(hexToAscii(address[0]));

        //长度,例如：写读条数据，长度为2,长度补足4位   位数为4，位数补足2位
        StringBuilder lengthBuilder = new StringBuilder();
        lengthBuilder.append(address.length);
        int length = lengthBuilder.length();
        for (int i = 0; i < 4 - length; i++) 
            lengthBuilder.insert(0, "0");
        
        //转ascii
        stringBuilder.append(hexToAscii(lengthBuilder.toString()));

        //LRC校验结果生成，去掉起始
        stringBuilder.append(getLrc(stringBuilder.substring(START.length())));
        //添加结束符
        stringBuilder.append(END);
        return stringBuilder.toString();
    

    //返回，是否是读请求的返回数据
    public boolean isReadRequest(String readString) 
        if (readString.length() < 30) 
            System.out.println("收到的数据响应格式不正确");
            return false;
        
        String startString = START + FRAME_HEADER;
        String command = readString.substring(startString.length(), startString.length()+READ_COMMAND.length() );
        return command.equals(READ_COMMAND);
    


    public String[] formatReadString(String readString) 
        String startString = START + FRAME_HEADER + READ_COMMAND;
        if (readString.startsWith(startString)) 
            if (readString.length() < 30) 
                System.out.println("收到的数据响应格式不正确");
                return null;
            
            String contentString = readString.substring(startString.length() + 4, readString.length() - 8);
            //数据为8位一组
            if (contentString.length() % 8 != 0) 
                System.out.println("收到的数据响应格式不正确");
                return null;
            

            int length = contentString.length() / 8;
            String[] contentArray = new String[length];
            for (int i = 0; i < length; i++) 
                //8位结果
                String data = contentString.substring(i * 8, i * 8 + 8);
                //ascii转16进制
                String hexString = asciiToHex(data);
                //16进制转10进制
                contentArray[i] = num16to10(hexString) + "";
            
            return contentArray;
        
        Flog.e(TAG, "无效数据");
        return null;
    

    private String getLrc(String hexdata) 
        StringBuilder rtu = new StringBuilder();
        int dealLength = hexdata.length() / 2;
        for (int i = 0; i < dealLength; i++) 
            String stringAscill = hexdata.substring(2 * i, 2 * i + 2);
            rtu.append(Integer.parseInt(stringAscill) - 30);
        
        int rtuLength = rtu.length() / 2;
        int sum = 0;
        for (int i = 0; i < rtuLength; i++) 
            sum += Integer.parseInt(rtu.substring(2 * i, 2 * i + 2), 16);
        

        //求和结果，补位成4位
        StringBuilder sumBuilder = new StringBuilder();
        sumBuilder.append(num10to16(sum).toUpperCase());
        int sumBuilderLength = sumBuilder.length();
        for (int i = 0; i < 4 - sumBuilderLength; i++) 
            sumBuilder.insert(0, "0");
        
        //补为4位的 只取低位
        String result = sumBuilder.substring(2, sumBuilder.length());
        return hexToAscii(num10to16(Integer.parseInt("100", 16) - Integer.parseInt(result, 16)).toUpperCase());
    

    private String hexInt(int total) 
        int a = total / 256;
        int b = total % 256;
        if (a > 255) 
            return hexInt(a) + format(b);
        
        return format(a) + format(b);
    

    private String format(int hex) 
        String hexa = Integer.toHexString(hex);
        int len = hexa.length();
        if (len < 2) 
            hexa = "0" + hexa;
        
        return hexa;
    

    /**
     * 10进制转16进制
     *
     * @param num
     * @return
     */
    private String num10to16(Integer num) 
        return Integer.toHexString(num);
    

    /**
     * 16进制转10进制
     */
    private int num16to10(String hexString) 
        int result = 0;
        try 
            result = new BigInteger(hexString, 16).intValue();
         catch (Exception e) 
            Flog.e(TAG, "数据解析失败");
        
        return result;
    

    /**
     * 16进制转ascii
     *
     * @param hex
     * @return
     */
    public String hexToAscii(String hex) 
        StringBuilder stringBuilder = new StringBuilder();
        for (int i = 0; i < hex.length(); i++) 
            char a = hex.charAt(i);
            int aInt = (int) a;
            stringBuilder.append(num10to16(aInt));
        
        return stringBuilder.toString();
    

    /**
     * ascii转16进制
     *
     * @param str
     * @return
     */
    private String asciiToHex(@NotNull String str) 
        byte[] hex = fromHex(str);
        StringBuilder result = new StringBuilder();
        for (byte b : hex) 
            result.append((char) b);
        
        return result.toString();
    

    /**
     * 字节数组转16进制
     *
     * @param bytes
     * @return
     */
    public String toHex(byte[] bytes) 
        StringBuilder sb = new StringBuilder(bytes.length * 2);
        byte[] arr = bytes;
        int len = bytes.length;

        for (int i = 0; i < len; ++i) 
            byte b = arr[i];
            sb.append(String.format("%02x", b));
        

        return sb.toString().toUpperCase();
    

    /**
     * string转16进制字节数组
     *
     * @param string
     * @return
     */
    public byte[] fromHex(String string) 
        byte[] result = new byte[string.length() / 2];

        for (int i = 0; i < result.length; ++i) 
            try 
                result[i] = (byte) Integer.parseInt(string.substring(i * 2, i * 2 + 2), 16);
             catch (Exception e) 
                Flog.e(TAG, "数据解析失败");
            
        
        return result;
    


    /**
     * hex字符串转byte数组
     *
     * @param inHex 待转换的Hex字符串
     * @return 转换后的byte数组结果
     */
    public byte[] hexToByteArray(String inHex) 
        int hexlen = inHex.length();
        byte[] result;
        if (hexlen % 2 == 1) 
            //奇数
            hexlen++;
            result = new byte[(hexlen / 2)];
            inHex = "0" + inHex;
         else 
            //偶数
            result = new byte[(hexlen / 2)];
        
        int j = 0;
        for (int i = 0; i < hexlen; i += 2) 
            result[j] = hexToByte(inHex.substring(i, i + 2));
            j++;
        
        return result;
    

    /**
     * Hex字符串转byte
     *
     * @param inHex 待转换的Hex字符串
     * @return 转换后的byte
     */
    public byte hexToByte(String inHex) 
        return (byte) Integer.parseInt(inHex, 16);
    

    /**
     * 字节数组转16进制
     *
     * @param bytes 需要转换的byte数组
     * @return 转换后的Hex字符串
     */
    public String bytesToHex(byte[] bytes) 
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < bytes.length; i++) 
            String hex = Integer.toHexString(bytes[i] & 0xFF);
            if (hex.length() < 2) 
                sb.append(0);
            
            sb.append(hex);
        
        return sb.toString();
    

关键代码都有注释，不再进行解释了

串口通信

串口通讯主要使用github上的开源项目AndroidSerialPort :“com.github.kongqw:AndroidSerialPort:1.0.1”
import进项目中后&