1.需求样例

举例5：浮点数参数读取（读取温度测量值）查看参数列表，温度测量值地址为320，根据Modbus协议，读取参数地址转换为16进制为：00H A0H，读取长度为2个字：00H 02H。
16进制发送读取命令如下：00 00 00 00 00 06 01 03 00 A0 00 02(复制使用时去掉中间空格，以16进制发送)00 00 00 00 00 06 01：Modbus命令头，用户直接复制，不能更改03：读取寄存器功能代码00 A0：读取参数寄存器地址16进制代码00 02：读取寄存器地址长度接收到数据格式如下：00 00 00 00 00 07 01 03 04 42 48 02 C8 00 00 00 00 00 07 01：Modbus返回命令头03：读取寄存器功能代码04：返回数据长度，四个字节42 48 02 C8：寄存器数据值，我们将此16进制数转换为浮点数值为：50.002716。注：具体转换方法可以常见附件转换程序算法。

2.实现功能

通过Java与Modbus-TCP/IP网络通讯实现举例5中的功能

3.功能代码

1）

package com.nwpusct.csal.controller.tcpconnect;
import java.io.*;
import java.math.BigInteger;
import java.net.Socket;import com.serotonin.modbus4j.exception.ErrorResponseException;
import com.serotonin.modbus4j.exception.ModbusInitException;
import com.serotonin.modbus4j.exception.ModbusTransportException;
import org.apache.commons.lang.math.NumberUtils;
import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;import javax.xml.bind.DatatypeConverter;import static org.apache.poi.util.HexDump.toHex;/*** 类描述：TODO** @author HBO* @date 2023-08-22 09:21**/
public class SocketUtils {private static final Logger LOGGER = LoggerFactory.getLogger(SocketUtils.class);private static Socket socket = null;private static String archivesCenterAPIIP = "127.0.0.1";private static String archivesCenterAPIPort ="502";public static boolean connection() {if (socket != null) {return true;}try {socket = new Socket(archivesCenterAPIIP, NumberUtils.toInt(archivesCenterAPIPort));return true;} catch (Exception e) {LOGGER.error("connection error", e);return false;}}public static void stop() {try {if (socket != null) {socket.close();socket = null;}} catch (Exception e) {LOGGER.error("connection error", e);}}/*** 发送数据** @param cmd*            需要发送的数据(十六进制的字符串形式)* @return 接受到的数据(十六进制的字符串形式)*/public static String sendCmd(String cmd) {if (!connection() || socket == null) {return "error";}try {OutputStream out = socket.getOutputStream();byte[] hexStrToByteArrs = hexStrToByteArrs(cmd);if (hexStrToByteArrs == null) {return "error";}out.write(hexStrToByteArrs);InputStream in = socket.getInputStream();byte[] buf = new byte[1024];int len = in.read(buf);stop();return bytesToHexString(buf) ;} catch (IOException e) {LOGGER.error("sendCmd error", e);return "error";}}/*** 将十六进制的字符串转换成字节数组** @param hexString* @return*/public static byte[] hexStrToByteArrs(String hexString) {if (StringUtils.isEmpty(hexString)) {return null;}hexString = hexString.replaceAll(" ", "");int len = hexString.length();int index = 0;byte[] bytes = new byte[len / 2];while (index < len) {String sub = hexString.substring(index, index + 2);bytes[index / 2] = (byte) Integer.parseInt(sub, 16);index += 2;}return bytes;}/*** 数组转换成十六进制字符串** @param* @return HexString*/public static final String bytesToHexString(byte[] bArray) {StringBuffer sb = new StringBuffer(bArray.length);String sTemp;for (int i = 0; i < bArray.length; i++) {sTemp = Integer.toHexString(0xFF & bArray[i]);if (sTemp.length() < 2)sb.append(0);sb.append(sTemp.toUpperCase());// 在这里故意追加一个逗号便于最后的区分sb.append(" ");}return sb.toString();}/** 将16进制数字解码成字符串,适用于所有字符（包括中文）*/public static String decode(String bytes) {String hexString = "0123456789ABCDEF";ByteArrayOutputStream baos = new ByteArrayOutputStream(bytes.length() / 2);// 将每2位16进制整数组装成一个字节for (int i = 0; i < bytes.length(); i += 2)baos.write((hexString.indexOf(bytes.charAt(i)) << 4 | hexString.indexOf(bytes.charAt(i + 1))));return new String(baos.toByteArray());}/*** 16进制数转换为浮点数值** @param str 16进制数据 424802C8= 50.002716* @throws IOException* @throws ModbusInitException* @throws ModbusTransportException* @throws ErrorResponseException*/public static Float intBitsToFloat(String str) {BigInteger b = new BigInteger(str, 16);float value = Float.intBitsToFloat(b.intValue());return value;}public static void main(String[] args) throws UnsupportedEncodingException {//34.6°String str = sendCmd("00 00 00 00 00 06 01 03 00 04 00 02");
//        String str="00 00 00 00 00 06 01 03 00 02 00 02";String x = str.replaceAll("\\s*", "");String s = str.split(" ")[8];String substring = x.substring(18, Integer.parseInt(s) * 2 + 18);System.out.println(substring);System.out.println(intBitsToFloat(substring));}}

2）

package com.nwpusct.csal.controller.tcpconnect;import com.nwpusct.csal.common.util.RestResult;
import com.nwpusct.csal.common.util.RestResultUtil;
import com.serotonin.modbus4j.ModbusFactory;
import com.serotonin.modbus4j.ModbusMaster;
import com.serotonin.modbus4j.code.DataType;
import com.serotonin.modbus4j.exception.ErrorResponseException;
import com.serotonin.modbus4j.exception.ModbusInitException;
import com.serotonin.modbus4j.exception.ModbusTransportException;
import com.serotonin.modbus4j.ip.IpParameters;
import com.serotonin.modbus4j.locator.BaseLocator;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.*;/*** 类描述：TODO* 监测高低温箱温度** @author HBO* @date 2023-08-21 09:34**/
@CrossOrigin
@RestController
@Api(tags = {"监测高低温箱温度"})
@RequestMapping(value = "/modbus")
public class ModbusController {@Value(value = "${high.ip}")public String ip;//从站IP@Value(value = "${high.port}")public int port;//modbus端口@Value(value = "${low.ip}")public String lowIp;@Value(value = "${low.port}")public int lowPort;/*** 工厂。*/static ModbusFactory modbusFactory;static {if (modbusFactory == null) {modbusFactory = new ModbusFactory();}}@GetMapping(value = "/readModbusHigh")@ApiOperation(value = "高温箱")public RestResult<Object> readModbusHigh() {//第二中方式try {Number number = readHoldingRegisterH(1, 320, DataType.FOUR_BYTE_FLOAT);return RestResultUtil.genSuccessResult(number);} catch (Exception e) {return RestResultUtil.genSuccessResult(null);}}/*** 获取master 高温箱** @return* @throws ModbusInitException*/public ModbusMaster getMasterH() throws ModbusInitException {IpParameters params = new IpParameters();params.setHost(ip);params.setPort(port);//// modbusFactory.createRtuMaster(wapper); //RTU 协议// modbusFactory.createUdpMaster(params);//UDP 协议// modbusFactory.createAsciiMaster(wrapper);//ASCII 协议ModbusMaster master = modbusFactory.createTcpMaster(params, false);// TCP 协议master.init();return master;}/*** 读取[03 Holding Register类型 2x]模拟量数据 高温箱** @param slaveId  slave Id* @param offset   位置 序列号* @param dataType 数据类型,来自com.serotonin.modbus4j.code.DataType* @return* @throws ModbusTransportException 异常* @throws ErrorResponseException   异常* @throws ModbusInitException      异常*/public Number readHoldingRegisterH(int slaveId, int offset, int dataType)throws ModbusTransportException, ErrorResponseException, ModbusInitException {// 03 Holding Register类型数据读取BaseLocator<Number> loc = BaseLocator.holdingRegister(slaveId, offset, dataType);Number value = getMasterH().getValue(loc);return value;}@GetMapping(value = "/readModbusLow")@ApiOperation(value = "高低温箱")public RestResult<Object> readModbusLow() {try {Number number = readHoldingRegisterL(1, 320, DataType.FOUR_BYTE_FLOAT);return RestResultUtil.genSuccessResult(number);} catch (Exception e) {return RestResultUtil.genSuccessResult(null);}}/*** 获取master 高低温箱** @return* @throws ModbusInitException*/public ModbusMaster getMasterL() throws ModbusInitException {IpParameters params = new IpParameters();params.setHost(lowIp);params.setPort(lowPort);ModbusMaster master = modbusFactory.createTcpMaster(params, false);// TCP 协议master.init();return master;}/*** 读取[03 Holding Register类型 2x]模拟量数据 高低温箱** @param slaveId  slave Id* @param offset   位置 序列号* @param dataType 数据类型,来自com.serotonin.modbus4j.code.DataType* @return* @throws ModbusTransportException 异常* @throws ErrorResponseException   异常* @throws ModbusInitException      异常*/public Number readHoldingRegisterL(int slaveId, int offset, int dataType)throws ModbusTransportException, ErrorResponseException, ModbusInitException {// 03 Holding Register类型数据读取BaseLocator<Number> loc = BaseLocator.holdingRegister(slaveId, offset, dataType);Number value = getMasterL().getValue(loc);return value;}
}

4.maven引入依赖包

 <dependencies><dependency><groupId>org.apache.commons</groupId><artifactId>commons-lang3</artifactId><version>3.9</version></dependency></dependencies><!-- 若想引用modbus4j需要引入下列repository id:ias-snapshots id:ias-releases 两个 ，使用默认仓库下载，不要使用阿里云仓库--><repositories><repository><releases><enabled>false</enabled></releases><snapshots><enabled>true</enabled></snapshots><id>ias-snapshots</id><name>Infinite Automation Snapshot Repository</name><url>https://maven.mangoautomation.net/repository/ias-snapshot/</url></repository><repository><releases><enabled>true</enabled></releases><snapshots><enabled>false</enabled></snapshots><id>ias-releases</id><name>Infinite Automation Release Repository</name><url>https://maven.mangoautomation.net/repository/ias-release/</url></repository></repositories>

5.测试模拟工具（私信关注博主）