net.wimpi.modbus.io.ModbusBINTransport Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of jamod Show documentation
Show all versions of jamod Show documentation
jamod is an object oriented implementation of the Modbus protocol, realized 100% in Java. It allows to quickly
realize master and slave applications in various transport flavors (IP and serial).
The newest version!
/***
* Copyright 2002-2010 jamod development team
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
***/
package net.wimpi.modbus.io;
import net.wimpi.modbus.Modbus;
import net.wimpi.modbus.ModbusCoupler;
import net.wimpi.modbus.ModbusIOException;
import net.wimpi.modbus.util.ModbusUtil;
import net.wimpi.modbus.msg.ModbusMessage;
import net.wimpi.modbus.msg.ModbusRequest;
import net.wimpi.modbus.msg.ModbusResponse;
import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
/**
* Class that implements the Modbus/BIN transport
* flavor.
*
* @author Dieter Wimberger
* @version 1.2 (@date@)
*/
public class ModbusBINTransport
extends ModbusSerialTransport {
private DataInputStream m_InputStream; //used to read from
private ASCIIOutputStream m_OutputStream; //used to write to
private byte[] m_InBuffer;
private BytesInputStream m_ByteIn; //to read message from
private BytesOutputStream m_ByteInOut; //to buffer message to
private BytesOutputStream m_ByteOut; //write frames
/**
* Constructs a new MobusBINTransport instance.
*/
public ModbusBINTransport() {
}//constructor
public void close() throws IOException {
m_InputStream.close();
m_OutputStream.close();
}//close
public void writeMessage(ModbusMessage msg)
throws ModbusIOException {
try {
int len;
synchronized (m_ByteOut) {
//write message to byte out
msg.setHeadless();
msg.writeTo(m_ByteOut);
byte[] buf = m_ByteOut.getBuffer();
len = m_ByteOut.size();
//write message
m_OutputStream.write(FRAME_START); //FRAMESTART
m_OutputStream.write(buf, 0, len); //PDU
int[] crc = ModbusUtil.calculateCRC(buf, 0, len); //CRC
m_OutputStream.write(crc[0]);
m_OutputStream.write(crc[1]);
m_OutputStream.write(FRAME_END); //FRAMEEND
m_OutputStream.flush();
m_ByteOut.reset();
}
// clears out the echoed message
// for RS485
if (m_Echo) {
// read back the echoed message
readEcho(len + 4);
}
} catch (Exception ex) {
throw new ModbusIOException("I/O failed to write");
}
}//writeMessage
public ModbusRequest readRequest()
throws ModbusIOException {
boolean done = false;
ModbusRequest request = null;
int in = -1;
try {
do {
//1. Skip to FRAME_START
while ((in = m_InputStream.read()) != FRAME_START) ;
//2. Read to FRAME_END
synchronized (m_InBuffer) {
m_ByteInOut.reset();
while ((in = m_InputStream.read()) != FRAME_END) {
m_ByteInOut.writeByte(in);
}
//check CRC
int[] crc = ModbusUtil.calculateCRC(m_InBuffer,0,m_ByteInOut.size()-2);
if (!(
m_InBuffer[m_ByteInOut.size()-2] == crc[0] //low byte first
&& m_InBuffer[m_ByteInOut.size()-1] == crc[1] //hibyte
)) {
continue;
}
m_ByteIn.reset(m_InBuffer, m_ByteInOut.size());
in = m_ByteIn.readUnsignedByte();
//check unit identifier
if (in != ModbusCoupler.getReference().getUnitID()) {
continue;
}
in = m_ByteIn.readUnsignedByte();
//create request
request = ModbusRequest.createModbusRequest(in);
request.setHeadless();
//read message
m_ByteIn.reset(m_InBuffer, m_ByteInOut.size());
request.readFrom(m_ByteIn);
}
done = true;
} while (!done);
return request;
} catch (Exception ex) {
if(Modbus.debug) System.out.println(ex.getMessage());
throw new ModbusIOException("I/O exception - failed to read.");
}
}//readRequest
public ModbusResponse readResponse()
throws ModbusIOException {
boolean done = false;
ModbusResponse response = null;
int in = -1;
try {
do {
//1. Skip to FRAME_START
while ((in = m_InputStream.read()) != FRAME_START) ;
//2. Read to FRAME_END
synchronized (m_InBuffer) {
m_ByteInOut.reset();
while ((in = m_InputStream.read()) != FRAME_END) {
m_ByteInOut.writeByte(in);
}
//check CRC
int[] crc = ModbusUtil.calculateCRC(m_InBuffer,0,m_ByteInOut.size()-2);
if (!(
m_InBuffer[m_ByteInOut.size()-2] == crc[0] //low byte first
&& m_InBuffer[m_ByteInOut.size()-1] == crc[1] //hibyte
)) {
continue;
}
m_ByteIn.reset(m_InBuffer, m_ByteInOut.size());
in = m_ByteIn.readUnsignedByte();
//check unit identifier
if (in != ModbusCoupler.getReference().getUnitID()) {
continue;
}
m_ByteIn.reset(m_InBuffer, m_ByteInOut.size());
in = m_ByteIn.readUnsignedByte();
//check unit identifier
if (in != ModbusCoupler.getReference().getUnitID()) {
continue;
}
in = m_ByteIn.readUnsignedByte();
//create request
response = ModbusResponse.createModbusResponse(in);
response.setHeadless();
//read message
m_ByteIn.reset(m_InBuffer, m_ByteInOut.size());
response.readFrom(m_ByteIn);
}
done = true;
} while (!done);
return response;
} catch (Exception ex) {
if(Modbus.debug) System.out.println(ex.getMessage());
throw new ModbusIOException("I/O exception - failed to read.");
}
}//readResponse
/**
* Prepares the input and output streams of this
* ModbusASCIITransport instance.
* The raw input stream will be wrapped into a
* filtered DataInputStream.
*
* @param in the input stream to be used for reading.
* @param out the output stream to be used for writing.
* @throws java.io.IOException if an I\O related error occurs.
*/
public void prepareStreams(InputStream in, OutputStream out) throws IOException {
m_InputStream = new DataInputStream(new ASCIIInputStream(in));
m_OutputStream = new ASCIIOutputStream(out);
m_ByteOut = new BytesOutputStream(Modbus.MAX_MESSAGE_LENGTH);
m_InBuffer = new byte[Modbus.MAX_MESSAGE_LENGTH];
m_ByteIn = new BytesInputStream(m_InBuffer);
m_ByteInOut = new BytesOutputStream(m_InBuffer);
}//prepareStreams
/**
* Defines a virtual number for the FRAME START token (COLON).
*/
public static final int FRAME_START = 1000;
/**
* Defines a virtual number for the FRAME_END token (CR LF).
*/
public static final int FRAME_END = 2000;
/**
* Defines the frame start token {.
*/
public static final int FRAME_START_TOKEN = 123;
/**
* Defines the frame end token }.
*/
public static final int FRAME_END_TOKEN = 125;
}//class ModbusASCIITransport