我使用jamod库实现了TCP Modbus Master 代码请求从Modbus保存寄存器并读取响应并将其写入文件。它还计算交易时间 这是我的代码：
public class TCPModbus_Task {
private static ModbusTCPMaster tcp_Modbusmaster;
public static void main(String[] args) {
int NoOfRequests = 0;// loop variable
int port = Modbus.DEFAULT_PORT;
int ref = 0; //the reference; offset where to start reading from i.e. the start address.
int count = 0; //the number of DI's to read
int repeat = 1; //a loop for repeating the transaction
String addr = null;
long Avg_diff = 0;
int reg_val = 0;
Register[] registers = new Register[200];
BufferedWriter output = null;
long Avg_Time = 0;
try {
//Setup Parameters
if(args.length < 3)
System.exit(1);
else {
try {
String astr = args[0];
int idx = astr.indexOf(':');
if(idx != -1) {
port = Integer.parseInt(astr.substring(idx+1));
addr = astr.substring(0, idx);
}
ref = Integer.decode(args[1]).intValue();
count = Integer.decode(args[2]).intValue();
if (args.length == 4) {
repeat = Integer.parseInt(args[3]);
}
} catch (Exception ex) {
ex.printStackTrace();
System.exit(1);
}
}
//ModbusTCPMaster instance ( constructor called )
tcp_Modbusmaster = new ModbusTCPMaster(addr, port);
//Connect to slave
tcp_Modbusmaster.connect();
//Create file write modbus data
File file = new File("D:/MODbusData.txt");
if (!file.exists()) {
file.createNewFile();
}
do {
Thread.sleep(1000);
//TimeStamp before request
Calendar cal = Calendar.getInstance(TimeZone.getTimeZone("GMT+5.30"));
long time1 = cal.getTimeInMillis();
String Time1 = String.valueOf(time1);
System.out.println("Time1 = " + time1);
//Read Modbus register (function code = 3)
registers = tcp_Modbusmaster.readMultipleRegisters(ref, count, 255);
System.out.println("Number of Modbus registers : " + registers.length);
System.out.println("\nModbus register values : \n");
for (int i=0; i<registers.length; i++)
{
System.out.println(registers[i].getValue());
}
//TimeStamp After response
Calendar cal1 = Calendar.getInstance(TimeZone.getTimeZone("GMT+5.30"));
long time2 = cal1.getTimeInMillis();
String Time2 = String.valueOf(time2);
System.out.println("Time2 = " + time2);
int diff = (int)(time2-time1);
String Transac_time = String.valueOf(diff);
System.out.println("Transacion(time2 - time1) time in ms=" + diff);
NoOfRequests++;
Avg_diff = Avg_diff + (long)diff;
//Writing Modbus data and transaction timing to file
output = new BufferedWriter(new FileWriter(file,true));
output.write("Time1 in ms: " + Time1 + "\n\r");
output.write("Modbus data: \n");
for(int i=0;i<registers.length;i++)
{
reg_val = registers[i].getValue();
String Register_value = String.valueOf(reg_val);
output.write(Register_value + " ");
}
output.write("\n" + "Time2 in ms: " + Time2 + "\n\r");
output.write("Transaction time in ms: " + Transac_time + "\n");
//Calculating the Average Transaction Time
if(NoOfRequests>=repeat)
{
Avg_Time = Avg_diff/NoOfRequests;
String AVG_Time = String.valueOf(Avg_Time);
output.write("Avg Transaction time in ms: " + AVG_Time + "\n\r");
}
output.close();
}while(NoOfRequests < repeat);
tcp_Modbusmaster.disconnect();
} catch( Exception ex ) {
ex.printStackTrace();
}
}
}
但是如果我将计数值（即从从站读取的字（寄存器）的数量）大于123，我想从Modbus从站读取200个保持寄存器（具有Modbus映射）。我可以毫无例外地在一个请求中读取count = 123寄存器。
它给出以下例外：
java.lang.IndexOutOfBoundsException
at java.io.BufferedInputStream.read(Unknown Source)
at java.io.DataInputStream.read(Unknown Source)
at net.aeplmm.modbus.io.ModbusTCPTransport.readResponse(ModbusTCPTransport.java:195)
at net.aeplmm.modbus.io.ModbusTCPTransaction.execute(ModbusTCPTransaction.java:192)
at net.aeplmm.modbus.facade.ModbusTCPMaster.readMultipleRegisters(ModbusTCPMaster.java:282)
at com.axonet.modbus.TCPModbus_Task.main(TCPModbus_Task.java:79)
java.io.EOFException
at java.io.DataInputStream.readUnsignedByte(Unknown Source)
at net.aeplmm.modbus.io.BytesInputStream.readUnsignedByte(BytesInputStream.java:169)
at net.aeplmm.modbus.io.ModbusTCPTransport.readResponse(ModbusTCPTransport.java:200)
at net.aeplmm.modbus.io.ModbusTCPTransaction.execute(ModbusTCPTransaction.java:192)
at net.aeplmm.modbus.facade.ModbusTCPMaster.readMultipleRegisters(ModbusTCPMaster.java:282)
at com.axonet.modbus.TCPModbus_Task.main(TCPModbus_Task.java:79)
java.io.EOFException
at java.io.DataInputStream.readUnsignedByte(Unknown Source)
at net.aeplmm.modbus.io.BytesInputStream.readUnsignedByte(BytesInputStream.java:169)
at net.aeplmm.modbus.io.ModbusTCPTransport.readResponse(ModbusTCPTransport.java:200)
at net.aeplmm.modbus.io.ModbusTCPTransaction.execute(ModbusTCPTransaction.java:192)
at net.aeplmm.modbus.facade.ModbusTCPMaster.readMultipleRegisters(ModbusTCPMaster.java:282)
at com.axonet.modbus.TCPModbus_Task.main(TCPModbus_Task.java:79)
java.io.EOFException
at java.io.DataInputStream.readUnsignedByte(Unknown Source)
at net.aeplmm.modbus.io.BytesInputStream.readUnsignedByte(BytesInputStream.java:169)
at net.aeplmm.modbus.io.ModbusTCPTransport.readResponse(ModbusTCPTransport.java:200)
at net.aeplmm.modbus.io.ModbusTCPTransaction.execute(ModbusTCPTransaction.java:192)
at net.aeplmm.modbus.facade.ModbusTCPMaster.readMultipleRegisters(ModbusTCPMaster.java:282)
at com.axonet.modbus.TCPModbus_Task.main(TCPModbus_Task.java:79)
net.aeplmm.modbus.ModbusIOException: Executing transaction failed (tried 3 times)
at net.aeplmm.modbus.io.ModbusTCPTransaction.execute(ModbusTCPTransaction.java:197)
at net.aeplmm.modbus.facade.ModbusTCPMaster.readMultipleRegisters(ModbusTCPMaster.java:282)
at com.axonet.modbus.TCPModbus_Task.main(TCPModbus_Task.java:79)
如果有人有任何建议会有所帮助。