Android基于Modbus RTU协议通过蓝牙与蓝牙串口开发板通信
前言实现原理在Android上实现Modbus RTU Master组装Modbus RTU消息帧ModbusErrorTypeModbusErrorModbusFunctionByteArrayWriterByteUtilCRC16ModbusRtuMaster完整代码在Android上实现用蓝牙传递Modbus Rtu协议帧字节数组转换为 16 进制字符串的方法最终效果前言
最近接到一位老师的项目，他们公司要求利用Android基于Modbus RTU协议通过蓝牙与蓝牙串口开发板通信，然后通过开发板控制硬件设备从而实现Android移动设备与硬件交互。所以今天我给大家分享下Android基于Modbus RTU协议的蓝牙通信。当然Android也可以直接通过串口利用Modbus RTU协议与开发板通信，或者基于Modbus TCP通信。至于非蓝牙非Modbus RTU协议通信，大家可以跳转到这位博主的博客：Steven Jon
实现原理
要想实现Android与开发板通信，那么必将涉及到协议问题。Android采用蓝牙协议通信，而开发板使用的是串口的协议(Modbus协议)，那么应该如何实现让采用两种不同协议通信的设备进行交互呢？那当然是两种协议的套接啦，接下来我将以Modbus RTU协议给大家介绍下实现原理：
(1) 在Android中我们不能直接将指令放在蓝牙帧的数据域内，因为这样不能满足Modbus RTU协议，因此开发板无法从蓝牙帧中正确解析出你的指令，所以我们应该先将指令数据按照Modbus RTU协议先进行指令封装，然后将封装好的Modbus RTU协议指令帧整个放在蓝牙帧的数据域内。这样当开发板获取蓝牙帧时会自动获取数据域内的数据，这时候将获取到含有指令的Modbus RTU协议帧，然后从含有指令的Modbus RTU协议帧中解析出指令操作。
(2) 当然开发板要想从蓝牙帧中自动提取数据域中的数据也是有条件的，那就是在开发板上必须加上串口转蓝牙接口。
这个串口转蓝牙接口就是实现两种协议套接的核心。它的作用是如果获取到的是Android发出的蓝牙帧时自动提取数据区域内的Modbus RTU协议帧，而如果收到的是开发板发出的Modbus RTU协议帧时则自动将它封装到蓝牙帧中。都是文字的话大家是不是很难理解，那么接下来上原理图：
套接原理图：
功能原理图：
看完实现原理接下来介绍最重要的代码实现。
在Android上实现Modbus RTU Master
在Android中针对Modbus RTU消息帧没有现成的组装模块，因此需要自己写。
组装Modbus RTU消息帧
这里是将输入的指令转换成对应的Modbus RTU协议的帧。
/*** 组装Modbus RTU消息帧* @param slave 从站地址号* @param function_code 功能码* @param starting_address 读取寄存器起始地址 / 写入寄存器地址 / 写入寄存器起始地址* @param quantity_of_x 读取寄存器个数 / 写入寄存器个数* @param output_value 需要写入单个寄存器的数值* @param output_values 需要写入多个寄存器的数组* @return 将整个消息帧转成byte[]* @throws ModbusError Modbus错误*/synchronized private byte[] execute(int slave, int function_code, int starting_address, int quantity_of_x,int output_value, int[] output_values) throws ModbusError {//检查参数是否符合协议规定if (slave < 0 || slave > 0xff) {throw new ModbusError(ModbusErrorType.ModbusInvalidArgumentError, "Invalid slave " + slave);}if (starting_address < 0 || starting_address > 0xffff) {throw new ModbusError(ModbusErrorType.ModbusInvalidArgumentError, "Invalid starting_address " + starting_address);}if (quantity_of_x < 1 || quantity_of_x > 0xff) {throw new ModbusError(ModbusErrorType.ModbusInvalidArgumentError, "Invalid quantity_of_x " + quantity_of_x);}// 构造requestByteArrayWriter request = new ByteArrayWriter();//写入从站地址号request.writeInt8(slave);//根据功能码组装数据区//如果为读取寄存器指令if (function_code == ModbusFunction.READ_COILS || function_code == ModbusFunction.READ_DISCRETE_INPUTS|| function_code == ModbusFunction.READ_INPUT_REGISTERS || function_code == ModbusFunction.READ_HOLDING_REGISTERS) {request.writeInt8(function_code);request.writeInt16(starting_address);request.writeInt16(quantity_of_x);} else if (function_code == ModbusFunction.WRITE_SINGLE_COIL || function_code == ModbusFunction.WRITE_SINGLE_REGISTER) {//写单个寄存器指令if (function_code == ModbusFunction.WRITE_SINGLE_COIL)if (output_value != 0) output_value = 0xff00;//如果为线圈寄存器（写1时为 FF 00,写0时为00 00）request.writeInt8(function_code);request.writeInt16(starting_address);request.writeInt16(output_value);} else if (function_code == ModbusFunction.WRITE_COILS) {//写多个线圈寄存器request.writeInt8(function_code);request.writeInt16(starting_address);request.writeInt16(quantity_of_x);//计算写入字节数int writeByteCount = (quantity_of_x / 8) + 1;/// 满足关系-> (w /8) + 1//写入数量 == 8 ,则写入字节数为1if (quantity_of_x % 8 == 0) {writeByteCount -= 1;}request.writeInt8(writeByteCount);int index = 0;//如果写入数据数量 > 8 ，则需要拆分开来int start = 0;//数组开始位置int end = 7;//数组结束位置int[] splitData = new int[8];//循环写入拆分数组，直到剩下最后一组 元素个数 <= 8 的数据while (writeByteCount > 1) {writeByteCount--;int sIndex = 0;for (index = start; index <= end; index++){splitData [sIndex++] = output_values[index];}//数据反转 对于是否要反转要看你传过来的数据，如果高低位顺序正确则不用反转splitData = reverseArr(splitData);//写入拆分数组request.writeInt8(toDecimal(splitData));start = index;end += 8;}//写入最后剩下的数据int last = quantity_of_x - index;int[] tData = new int[last];System.arraycopy(output_values, index, tData, 0, last);//数据反转 对于是否要反转要看你传过来的数据，如果高低位顺序正确则不用反转tData = reverseArr(tData);request.writeInt8(toDecimal(tData));} else if (function_code == ModbusFunction.WRITE_HOLDING_REGISTERS) {//写多个保持寄存器request.writeInt8(function_code);request.writeInt16(starting_address);request.writeInt16(quantity_of_x);request.writeInt8(2 * quantity_of_x);//写入数据for (int v : output_values) {request.writeInt16(v);}} else {throw new ModbusError(ModbusErrorType.ModbusFunctionNotSupportedError, "Not support function " + function_code);}byte[] bytes = request.toByteArray();//计算CRC校验码int crc = pute(bytes);request.writeInt16Reversal(crc);bytes = request.toByteArray();return bytes;}
ModbusErrorType
定义Modbus通讯错误类型
/*** 常见的Modbus通讯错误*/public enum ModbusErrorType {ModbusError,ModbusFunctionNotSupportedError,ModbusDuplicatedKeyError,ModbusMissingKeyError,ModbusInvalidBlockError,ModbusInvalidArgumentError,ModbusOverlapBlockError,ModbusOutOfBlockError,ModbusInvalidResponseError,ModbusInvalidRequestError,ModbusTimeoutError}
ModbusError
public class ModbusError extends Exception {private int code;public ModbusError(int code, String message) {super(!TextUtils.isEmpty(message) ? message : "Modbus Error: Exception code = " + code);this.code = code;}public ModbusError(int code) {this(code, null);}public ModbusError(ModbusErrorType type, String message) {super(type.name() + ": " + message);}public ModbusError(String message) {super(message);}public int getCode() {return this.code;}}
ModbusFunction
功能码定义
/*** 功能码（十进制显示）*/public class ModbusFunction {//读线圈寄存器public static final int READ_COILS = 1;//读离散输入寄存器public static final int READ_DISCRETE_INPUTS = 2;//读保持寄存器public static final int READ_HOLDING_REGISTERS = 3;//读输入寄存器public static final int READ_INPUT_REGISTERS = 4;//写单个线圈寄存器public static final int WRITE_SINGLE_COIL = 5;//写单个保持寄存器public static final int WRITE_SINGLE_REGISTER = 6;//写入多个线圈寄存器public static final int WRITE_COILS = 15;//写入多个保持寄存器public static final int WRITE_HOLDING_REGISTERS = 16;}
ByteArrayWriter
public class ByteArrayWriter extends ByteArrayOutputStream {public ByteArrayWriter() {super();}public void writeInt8(byte b){this.write(b);}public void writeInt8(int b){this.write((byte)b);}public void writeInt16(int n) {byte[] bytes = ByteUtil.fromInt16(n);this.write(bytes, 0, bytes.length);}public void writeInt16Reversal(int n){byte[] bytes=ByteUtil.fromInt16Reversal(n);this.write(bytes,0,bytes.length);}public void writeInt32(int n) {byte[] bytes = ByteUtil.fromInt32(n);this.write(bytes, 0, bytes.length);}public void writeBytes(byte[] bs,int len){this.write(bs,0,len);}}
ByteUtil
public class ByteUtil {public static String toHexString(byte[] input, String separator) {if (input==null) return null;StringBuilder sb = new StringBuilder();for (int i = 0; i < input.length; i++) {if (separator != null && sb.length() > 0) {sb.append(separator);}String str = Integer.toHexString(input[i] & 0xff);if (str.length() == 1) str = "0" + str;sb.append(str);}return sb.toString();}public static String toHexString(byte[] input) {return toHexString(input, " ");}public static byte[] fromInt32(int input){byte[] result=new byte[4];result[3]=(byte)(input >> 24 & 0xFF);result[2]=(byte)(input >> 16 & 0xFF);result[1]=(byte)(input >> 8 & 0xFF);result[0]=(byte)(input & 0xFF);return result;}public static byte[] fromInt16(int input){byte[] result=new byte[2];result[0]=(byte)(input >> 8 & 0xFF);result[1]=(byte)(input & 0xFF);return result;}public static byte[] fromInt16Reversal(int input){byte[] result=new byte[2];result[1]=(byte)(input>>8&0xFF);result[0]=(byte)(input&0xFF);return result;}}
CRC16
public class CRC16 {private static final byte[] crc16_tab_h = {(byte) 0x00, (byte) 0xC1, (byte) 0x81, (byte) 0x40,(byte) 0x01, (byte) 0xC0, (byte) 0x80, (byte) 0x41, (byte) 0x01, (byte) 0xC0, (byte) 0x80,(byte) 0x41, (byte) 0x00, (byte) 0xC1, (byte) 0x81, (byte) 0x40, (byte) 0x01, (byte) 0xC0,(byte) 0x80, (byte) 0x41, (byte) 0x00, (byte) 0xC1, (byte) 0x81, (byte) 0x40, (byte) 0x00,(byte) 0xC1, (byte) 0x81, (byte) 0x40, (byte) 0x01, (byte) 0xC0, (byte) 0x80, (byte) 0x41,(byte) 0x01, (byte) 0xC0, (byte) 0x80, (byte) 0x41, (byte) 0x00, (byte) 0xC1, (byte) 0x81,(byte) 0x40, (byte) 0x00, (byte) 0xC1, (byte) 0x81, (byte) 0x40, (byte) 0x01, (byte) 0xC0,(byte) 0x80, (byte) 0x41, (byte) 0x00, (byte) 0xC1, (byte) 0x81, (byte) 0x40, (byte) 0x01,(byte) 0xC0, (byte) 0x80, (byte) 0x41, (byte) 0x01, (byte) 0xC0, (byte) 0x80, (byte) 0x41,(byte) 0x00, (byte) 0xC1, (byte) 0x81, (byte) 0x40, (byte) 0x01, (byte) 0xC0, (byte) 0x80,(byte) 0x41, (byte) 0x00, (byte) 0xC1, (byte) 0x81, (byte) 0x40, (byte) 0x00, (byte) 0xC1,(byte) 0x81, (byte) 0x40, (byte) 0x01, (byte) 0xC0, (byte) 0x80, (byte) 0x41, (byte) 0x00,(byte) 0xC1, (byte) 0x81, (byte) 0x40, (byte) 0x01, (byte) 0xC0, (byte) 0x80, (byte) 0x41,(byte) 0x01, (byte) 0xC0, (byte) 0x80, (byte) 0x41, (byte) 0x00, (byte) 0xC1, (byte) 0x81,(byte) 0x40, (byte) 0x00, (byte) 0xC1, (byte) 0x81, (byte) 0x40, (byte) 0x01, (byte) 0xC0,(byte) 0x80, (byte) 0x41, (byte) 0x01, (byte) 0xC0, (byte) 0x80, (byte) 0x41, (byte) 0x00,(byte) 0xC1, (byte) 0x81, (byte) 0x40, (byte) 0x01, (byte) 0xC0, (byte) 0x80, (byte) 0x41,(byte) 0x00, (byte) 0xC1, (byte) 0x81, (byte) 0x40, (byte) 0x00, (byte) 0xC1, (byte) 0x81,(byte) 0x40, (byte) 0x01, (byte) 0xC0, (byte) 0x80, (byte) 0x41, (byte) 0x01, (byte) 0xC0,(byte) 0x80, (byte) 0x41, (byte) 0x00, (byte) 0xC1, (byte) 0x81, (byte) 0x40, (byte) 0x00,(byte) 0xC1, (byte) 0x81, (byte) 0x40, (byte) 0x01, (byte) 0xC0, (byte) 0x80, (byte) 0x41,(byte) 0x00, (byte) 0xC1, (byte) 0x81, (byte) 0x40, (byte) 0x01, (byte) 0xC0, (byte) 0x80,(byte) 0x41, (byte) 0x01, (byte) 0xC0, (byte) 0x80, (byte) 0x41, (byte) 0x00, (byte) 0xC1,(byte) 0x81, (byte) 0x40, (byte) 0x00, (byte) 0xC1, (byte) 0x81, (byte) 0x40, (byte) 0x01,(byte) 0xC0, (byte) 0x80, (byte) 0x41, (byte) 0x01, (byte) 0xC0, (byte) 0x80, (byte) 0x41,(byte) 0x00, (byte) 0xC1, (byte) 0x81, (byte) 0x40, (byte) 0x01, (byte) 0xC0, (byte) 0x80,(byte) 0x41, (byte) 0x00, (byte) 0xC1, (byte) 0x81, (byte) 0x40, (byte) 0x00, (byte) 0xC1,(byte) 0x81, (byte) 0x40, (byte) 0x01, (byte) 0xC0, (byte) 0x80, (byte) 0x41, (byte) 0x00,(byte) 0xC1, (byte) 0x81, (byte) 0x40, (byte) 0x01, (byte) 0xC0, (byte) 0x80, (byte) 0x41,(byte) 0x01, (byte) 0xC0, (byte) 0x80, (byte) 0x41, (byte) 0x00, (byte) 0xC1, (byte) 0x81,(byte) 0x40, (byte) 0x01, (byte) 0xC0, (byte) 0x80, (byte) 0x41, (byte) 0x00, (byte) 0xC1,(byte) 0x81, (byte) 0x40, (byte) 0x00, (byte) 0xC1, (byte) 0x81, (byte) 0x40, (byte) 0x01,(byte) 0xC0, (byte) 0x80, (byte) 0x41, (byte) 0x01, (byte) 0xC0, (byte) 0x80, (byte) 0x41,(byte) 0x00, (byte) 0xC1, (byte) 0x81, (byte) 0x40, (byte) 0x00, (byte) 0xC1, (byte) 0x81,(byte) 0x40, (byte) 0x01, (byte) 0xC0, (byte) 0x80, (byte) 0x41, (byte) 0x00, (byte) 0xC1,(byte) 0x81, (byte) 0x40, (byte) 0x01, (byte) 0xC0, (byte) 0x80, (byte) 0x41, (byte) 0x01,(byte) 0xC0, (byte) 0x80, (byte) 0x41, (byte) 0x00, (byte) 0xC1, (byte) 0x81, (byte) 0x40 };private static final byte[] crc16_tab_l = {(byte) 0x00, (byte) 0xC0, (byte) 0xC1, (byte) 0x01,(byte) 0xC3, (byte) 0x03, (byte) 0x02, (byte) 0xC2, (byte) 0xC6, (byte) 0x06, (byte) 0x07,(byte) 0xC7, (byte) 0x05, (byte) 0xC5, (byte) 0xC4, (byte) 0x04, (byte) 0xCC, (byte) 0x0C,(byte) 0x0D, (byte) 0xCD, (byte) 0x0F, (byte) 0xCF, (byte) 0xCE, (byte) 0x0E, (byte) 0x0A,(byte) 0xCA, (byte) 0xCB, (byte) 0x0B, (byte) 0xC9, (byte) 0x09, (byte) 0x08, (byte) 0xC8,(byte) 0xD8, (byte) 0x18, (byte) 0x19, (byte) 0xD9, (byte) 0x1B, (byte) 0xDB, (byte) 0xDA,(byte) 0x1A, (byte) 0x1E, (byte) 0xDE, (byte) 0xDF, (byte) 0x1F, (byte) 0xDD, (byte) 0x1D,(byte) 0x1C, (byte) 0xDC, (byte) 0x14, (byte) 0xD4, (byte) 0xD5, (byte) 0x15, (byte) 0xD7,(byte) 0x17, (byte) 0x16, (byte) 0xD6, (byte) 0xD2, (byte) 0x12, (byte) 0x13, (byte) 0xD3,(byte) 0x11, (byte) 0xD1, (byte) 0xD0, (byte) 0x10, (byte) 0xF0, (byte) 0x30, (byte) 0x31,(byte) 0xF1, (byte) 0x33, (byte) 0xF3, (byte) 0xF2, (byte) 0x32, (byte) 0x36, (byte) 0xF6,(byte) 0xF7, (byte) 0x37, (byte) 0xF5, (byte) 0x35, (byte) 0x34, (byte) 0xF4, (byte) 0x3C,(byte) 0xFC, (byte) 0xFD, (byte) 0x3D, (byte) 0xFF, (byte) 0x3F, (byte) 0x3E, (byte) 0xFE,(byte) 0xFA, (byte) 0x3A, (byte) 0x3B, (byte) 0xFB, (byte) 0x39, (byte) 0xF9, (byte) 0xF8,(byte) 0x38, (byte) 0x28, (byte) 0xE8, (byte) 0xE9, (byte) 0x29, (byte) 0xEB, (byte) 0x2B,(byte) 0x2A, (byte) 0xEA, (byte) 0xEE, (byte) 0x2E, (byte) 0x2F, (byte) 0xEF, (byte) 0x2D,(byte) 0xED, (byte) 0xEC, (byte) 0x2C, (byte) 0xE4, (byte) 0x24, (byte) 0x25, (byte) 0xE5,(byte) 0x27, (byte) 0xE7, (byte) 0xE6, (byte) 0x26, (byte) 0x22, (byte) 0xE2, (byte) 0xE3,(byte) 0x23, (byte) 0xE1, (byte) 0x21, (byte) 0x20, (byte) 0xE0, (byte) 0xA0, (byte) 0x60,(byte) 0x61, (byte) 0xA1, (byte) 0x63, (byte) 0xA3, (byte) 0xA2, (byte) 0x62, (byte) 0x66,(byte) 0xA6, (byte) 0xA7, (byte) 0x67, (byte) 0xA5, (byte) 0x65, (byte) 0x64, (byte) 0xA4,(byte) 0x6C, (byte) 0xAC, (byte) 0xAD, (byte) 0x6D, (byte) 0xAF, (byte) 0x6F, (byte) 0x6E,(byte) 0xAE, (byte) 0xAA, (byte) 0x6A, (byte) 0x6B, (byte) 0xAB, (byte) 0x69, (byte) 0xA9,(byte) 0xA8, (byte) 0x68, (byte) 0x78, (byte) 0xB8, (byte) 0xB9, (byte) 0x79, (byte) 0xBB,(byte) 0x7B, (byte) 0x7A, (byte) 0xBA, (byte) 0xBE, (byte) 0x7E, (byte) 0x7F, (byte) 0xBF,(byte) 0x7D, (byte) 0xBD, (byte) 0xBC, (byte) 0x7C, (byte) 0xB4, (byte) 0x74, (byte) 0x75,(byte) 0xB5, (byte) 0x77, (byte) 0xB7, (byte) 0xB6, (byte) 0x76, (byte) 0x72, (byte) 0xB2,(byte) 0xB3, (byte) 0x73, (byte) 0xB1, (byte) 0x71, (byte) 0x70, (byte) 0xB0, (byte) 0x50,(byte) 0x90, (byte) 0x91, (byte) 0x51, (byte) 0x93, (byte) 0x53, (byte) 0x52, (byte) 0x92,(byte) 0x96, (byte) 0x56, (byte) 0x57, (byte) 0x97, (byte) 0x55, (byte) 0x95, (byte) 0x94,(byte) 0x54, (byte) 0x9C, (byte) 0x5C, (byte) 0x5D, (byte) 0x9D, (byte) 0x5F, (byte) 0x9F,(byte) 0x9E, (byte) 0x5E, (byte) 0x5A, (byte) 0x9A, (byte) 0x9B, (byte) 0x5B, (byte) 0x99,(byte) 0x59, (byte) 0x58, (byte) 0x98, (byte) 0x88, (byte) 0x48, (byte) 0x49, (byte) 0x89,(byte) 0x4B, (byte) 0x8B, (byte) 0x8A, (byte) 0x4A, (byte) 0x4E, (byte) 0x8E, (byte) 0x8F,(byte) 0x4F, (byte) 0x8D, (byte) 0x4D, (byte) 0x4C, (byte) 0x8C, (byte) 0x44, (byte) 0x84,(byte) 0x85, (byte) 0x45, (byte) 0x87, (byte) 0x47, (byte) 0x46, (byte) 0x86, (byte) 0x82,(byte) 0x42, (byte) 0x43, (byte) 0x83, (byte) 0x41, (byte) 0x81, (byte) 0x80, (byte) 0x40 };/*** 计算CRC16校验** @param data* 需要计算的数组* @return CRC16校验值*/public static int compute(byte[] data) {return compute(data, 0, data.length);}/*** 计算CRC16校验** @param data* 需要计算的数组* @param offset* 起始位置* @param len* 长度* @return CRC16校验值*/public static int compute(byte[] data, int offset, int len) {return compute(data, offset, len, 0xffff);}/*** 计算CRC16校验** @param data* 需要计算的数组* @param offset* 起始位置* @param len* 长度* @param preval* 之前的校验值* @return CRC16校验值*/public static int compute(byte[] data, int offset, int len, int preval) {int ucCRCHi = (preval & 0xff00) >> 8;int ucCRCLo = preval & 0x00ff;int iIndex;for (int i = 0; i < len; ++i) {iIndex = (ucCRCLo ^ data[offset + i]) & 0x00ff;ucCRCLo = ucCRCHi ^ crc16_tab_h[iIndex];ucCRCHi = crc16_tab_l[iIndex];}int result=((ucCRCHi & 0x00ff) << 8) | (ucCRCLo & 0x00ff) & 0xffff;return result;}}
ModbusRtuMaster完整代码
这个类主要的功能就是将输入的指令转换成符合ModbusRtu协议的指令并返回，之后Android只需将返回的byte[]类型的值用蓝牙发送即可。
import java.util.Formatter;public class ModbusRtuMaster {/*** 组装Modbus RTU消息帧** @param slave 从站地址号* @param function_code 功能码* @param starting_address 读取寄存器起始地址 / 写入寄存器地址 / 写入寄存器起始地址* @param quantity_of_x 读取寄存器个数 / 写入寄存器个数* @param output_value需要写入单个寄存器的数值* @param output_values 需要写入多个寄存器的数组* @return 将整个消息帧转成byte[]* @throws ModbusError Modbus错误*/synchronized private byte[] execute(int slave, int function_code, int starting_address, int quantity_of_x,int output_value, int[] output_values) throws ModbusError {//检查参数是否符合协议规定if (slave < 0 || slave > 0xff) {throw new ModbusError(ModbusErrorType.ModbusInvalidArgumentError, "Invalid slave " + slave);}if (starting_address < 0 || starting_address > 0xffff) {throw new ModbusError(ModbusErrorType.ModbusInvalidArgumentError, "Invalid starting_address " + starting_address);}if (quantity_of_x < 1 || quantity_of_x > 0xff) {throw new ModbusError(ModbusErrorType.ModbusInvalidArgumentError, "Invalid quantity_of_x " + quantity_of_x);}// 构造requestByteArrayWriter request = new ByteArrayWriter();//写入从站地址号request.writeInt8(slave);//根据功能码组装数据区//如果为读取寄存器指令if (function_code == ModbusFunction.READ_COILS || function_code == ModbusFunction.READ_DISCRETE_INPUTS|| function_code == ModbusFunction.READ_INPUT_REGISTERS || function_code == ModbusFunction.READ_HOLDING_REGISTERS) {request.writeInt8(function_code);request.writeInt16(starting_address);request.writeInt16(quantity_of_x);} else if (function_code == ModbusFunction.WRITE_SINGLE_COIL || function_code == ModbusFunction.WRITE_SINGLE_REGISTER) {//写单个寄存器指令if (function_code == ModbusFunction.WRITE_SINGLE_COIL)if (output_value != 0) output_value = 0xff00;//如果为线圈寄存器（写1时为 FF 00,写0时为00 00）request.writeInt8(function_code);request.writeInt16(starting_address);request.writeInt16(output_value);} else if (function_code == ModbusFunction.WRITE_COILS) {//写多个线圈寄存器request.writeInt8(function_code);request.writeInt16(starting_address);request.writeInt16(quantity_of_x);//计算写入字节数int writeByteCount = (quantity_of_x / 8) + 1;/// 满足关系-> (w /8) + 1//写入数量 == 8 ,则写入字节数为1if (quantity_of_x % 8 == 0) {writeByteCount -= 1;}request.writeInt8(writeByteCount);int index = 0;//如果写入数据数量 > 8 ，则需要拆分开来int start = 0;//数组开始位置int end = 7;//数组结束位置int[] splitData = new int[8];//循环写入拆分数组，直到剩下最后一组 元素个数 <= 8 的数据while (writeByteCount > 1) {writeByteCount--;int sIndex = 0;for (index = start; index <= end; index++) {splitData[sIndex++] = output_values[index];}//数据反转 对于是否要反转要看你传过来的数据，如果高低位顺序正确则不用反转splitData = reverseArr(splitData);//写入拆分数组request.writeInt8(toDecimal(splitData));start = index;end += 8;}//写入最后剩下的数据int last = quantity_of_x - index;int[] tData = new int[last];System.arraycopy(output_values, index, tData, 0, last);//数据反转 对于是否要反转要看你传过来的数据，如果高低位顺序正确则不用反转tData = reverseArr(tData);request.writeInt8(toDecimal(tData));} else if (function_code == ModbusFunction.WRITE_HOLDING_REGISTERS) {//写多个保持寄存器request.writeInt8(function_code);request.writeInt16(starting_address);request.writeInt16(quantity_of_x);request.writeInt8(2 * quantity_of_x);//写入数据for (int v : output_values) {request.writeInt16(v);}} else {throw new ModbusError(ModbusErrorType.ModbusFunctionNotSupportedError, "Not support function " + function_code);}byte[] bytes = request.toByteArray();//计算CRC校验码int crc = pute(bytes);request.writeInt16Reversal(crc);bytes = request.toByteArray();return bytes;}/*** 读多个线圈寄存器** @param slave从站地址* @param startAddress 起始地址* @param numberOfPoints 读取线圈寄存器个数* @throws ModbusError Modbus错误*/public byte[] readCoils(int slave, int startAddress, int numberOfPoints) throws ModbusError {byte[] sendBytes = execute(slave, ModbusFunction.READ_COILS, startAddress, numberOfPoints, 0, null);return sendBytes;}//读单个线圈寄存器public byte[] readCoil(int slave, int address) throws ModbusError {byte[] sendBytes = readCoils(slave, address, 1);return sendBytes;}/*** 读多个保持寄存器** @param slave从站地址* @param startAddress 起始地址* @param numberOfPoints 读取保持寄存器个数* @throws ModbusError Modbus错误*/public byte[] readHoldingRegisters(int slave, int startAddress, int numberOfPoints) throws ModbusError {byte[] sendBytes = execute(slave, ModbusFunction.READ_HOLDING_REGISTERS, startAddress, numberOfPoints, 0, null);return sendBytes;}//读单个保持寄存器public byte[] readHoldingRegister(int slave, int address) throws ModbusError {byte[] sendBytes = readHoldingRegisters(slave, address, 1);return sendBytes;}/*** 读多个输入寄存器** @param slave从站地址* @param startAddress 起始地址* @param numberOfPoints 读取输入寄存器个数* @throws ModbusError Modbus错误*/public byte[] readInputRegisters(int slave, int startAddress, int numberOfPoints) throws ModbusError {byte[] sendBytes = execute(slave, ModbusFunction.READ_INPUT_REGISTERS, startAddress, numberOfPoints, 0, null);return sendBytes;}//读单个输入寄存器public byte[] readInputRegister(int slave, int address) throws ModbusError {byte[] sendBytes = readInputRegisters(slave, address, 1);return sendBytes;}/*** 读多个离散输入寄存器** @param slave从站地址* @param startAddress 起始地址* @param numberOfPoints 读取离散输入寄存器个数* @throws ModbusError Modbus错误*/public byte[] readDiscreteInputs(int slave, int startAddress, int numberOfPoints) throws ModbusError {byte[] sendBytes = execute(slave, ModbusFunction.READ_DISCRETE_INPUTS, startAddress, numberOfPoints, 0, null);return sendBytes;}//读单个离散输入寄存器public byte[] readDiscreteInput(int slave, int address) throws ModbusError {byte[] sendBytes = readDiscreteInputs(slave, address, 1);return sendBytes;}/*** 写单个线圈寄存器** @param slave 从站地址* @param address 写入寄存器地址* @param value 写入值（true/false)* @throws ModbusError Modbus错误*/public byte[] writeSingleCoil(int slave, int address, boolean value) throws ModbusError {byte[] sendBytes = execute(slave, ModbusFunction.WRITE_SINGLE_COIL, address, 1, value ? 1 : 0, null);return sendBytes;}/*** 写单个保持寄存器** @param slave 从站地址* @param address 写入寄存器地址* @param value 写入值* @throws ModbusError Modbus错误*/public byte[] writeSingleRegister(int slave, int address, int value) throws ModbusError {byte[] sendBytes = execute(slave, ModbusFunction.WRITE_SINGLE_REGISTER, address, 1, value, null);return sendBytes;}/*** 写入多个保持寄存器** @param slave 从站地址* @param address 写入寄存器地址* @param sCount 写入寄存器个数* @param data 写入数据* @throws ModbusError*/public byte[] writeHoldingRegisters(int slave, int address, int sCount, int[] data) throws ModbusError {byte[] sendBytes = execute(slave, ModbusFunction.WRITE_HOLDING_REGISTERS, address, sCount, 0, data);return sendBytes;}/*** 写入多个位** @param slave 从站地址* @param address 写入寄存器地址* @param bCount 写入寄存器个数* @param data 写入数据{1,0}* @throws ModbusError*/public byte[] writeCoils(int slave, int address, int bCount, int[] data) throws ModbusError {byte[] sendBytes = execute(slave, ModbusFunction.WRITE_COILS, address, bCount, 0, data);return sendBytes;}//将数组反转private int[] reverseArr(int[] arr) {int[] tem = new int[arr.length];for (int i = 0; i < arr.length; i++) {tem[i] = arr[arr.length - 1 - i];}return tem;}/*** 字节转换为 16 进制字符串** @param b 字节* @return Hex 字符串*/static String byte2Hex(byte b) {StringBuilder hex = new StringBuilder(Integer.toHexString(b));if (hex.length() > 2) {hex = new StringBuilder(hex.substring(hex.length() - 2));}while (hex.length() < 2) {hex.insert(0, "0");}return hex.toString();}/*** 字节数组转换为 16 进制字符串** @param bytes 字节数组* @return Hex 字符串*/static String bytes2Hex(byte[] bytes) {Formatter formatter = new Formatter();for (byte b : bytes) {formatter.format("%02x ", b);}String hash = formatter.toString();formatter.close();return hash;}//将int[1,0,0,1,1,0]数组转换为十进制数据private int toDecimal(int[] data) {int result = 0;if (data != null) {StringBuilder sData = new StringBuilder();for (int d : data) {sData.append(d);}try {result = Integer.parseInt(sData.toString(), 2);} catch (NumberFormatException e) {result = -1;}}return result;}}
在Android上实现用蓝牙传递Modbus Rtu协议帧
今天分享的是Android如何基于Modbus RTU协议与蓝牙串口开发板通信，至于Android如何搜索蓝牙设备，如何连接我这就不多做介绍了，网上有很多博主做了一大堆了。接下来来看看我们写好的ModbusRtuMaster怎么使用吧。
//首先在你的activity中定义一个ModbusRtuMaster类型private ModbusRtuMaster modbusRtuMaster;//然后在activity中的onCreate方法里初始化ModbusRtuMastermodbusRtuMaster = new ModbusRtuMaster();//最后利用ModbusRtuMaster对输入的指令进行协议封装并接收返回结果//这时候results就是一个符合ModbusRtu协议的消息针了byte[] results = modbusRtuMaster.writeHoldingRegisters(Rs485, Rsaddress, Hvalue.length, Hvalue);//接下来可以把results用蓝牙发给你的蓝牙串口开发板了private final OutputStream mmOutStream;mmOutStream.write(results)
字节数组转换为 16 进制字符串的方法
这里我再提下ModbusRtuMaster里面的bytes2Hex方法，如果你想把转换后的指令或者是串口返回的数据显示在Android设备上，那么必须将其转化为Hex类型的16进制字符串，如果不转换成Hex那么显示出来将是乱码等，因为那些数据是btye类型，然后就是这里不能使用
new String(byte[])
去将byte数组转换成string，否则将显示成符号字母，请务必按照我在ModbusRtuMaster内写的bytes2Hex将字节数组转换为 16 进制字符串，再输出显示。
static String bytes2Hex(byte[] bytes) {Formatter formatter = new Formatter();for (byte b : bytes) {formatter.format("%02x ", b);}String hash = formatter.toString();formatter.close();return hash;}
如何使用bytes2Hex
String result = modbusRtuMaster.bytes2Hex(results);
最终效果
最后让我们来看看使用ModbusRtuMaster返回帧通过蓝牙传给蓝牙串口开发板的效果吧！(蓝色代表发送指令，绿色代表接收开发板返回的数据)
以上就是《Android基于ModbusRtu协议通过蓝牙与蓝牙串口开发板通信》的全部内容了，我也是第一次使用Android去通信开发板与硬件交互。这里非常感谢另一位博主的文章 Steven Jon，我也是借鉴了他博客中的一篇关于ModbusRtuMaster的文章才实现通信的，对其他通信方法感兴趣的小伙伴可以点击去Steven Jon大佬的博客继续学习。
