net.wimpi.modbus.msg.ReadCoilsRequest Maven / Gradle / Ivy
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/***
* 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.msg;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import net.wimpi.modbus.Modbus;
import net.wimpi.modbus.ModbusCoupler;
import net.wimpi.modbus.procimg.DigitalOut;
import net.wimpi.modbus.procimg.IllegalAddressException;
import net.wimpi.modbus.procimg.ProcessImage;
/**
* Class implementing a ReadCoilsRequest.
* The implementation directly correlates with the class 1
* function read coils (FC 1). It encapsulates
* the corresponding request message.
*
* Coils are understood as bits that can be manipulated
* (i.e. set or unset).
*
* @author Dieter Wimberger
* @version 1.2 (@date@)
*/
public final class ReadCoilsRequest
extends ModbusRequest {
//instance attributes
private int m_Reference;
private int m_BitCount;
/**
* Constructs a new ReadCoilsRequest
* instance.
*/
public ReadCoilsRequest() {
super();
setFunctionCode(Modbus.READ_COILS);
//4 bytes (unit id and function code is excluded)
setDataLength(4);
}//constructor
/**
* Constructs a new ReadCoilsRequest
* instance with a given reference and count of coils
* (i.e. bits) to be read.
*
* @param ref the reference number of the register
* to read from.
* @param count the number of bits to be read.
*/
public ReadCoilsRequest(int ref, int count) {
super();
setFunctionCode(Modbus.READ_COILS);
//4 bytes (unit id and function code is excluded)
setDataLength(4);
setReference(ref);
setBitCount(count);
}//constructor
public ModbusResponse createResponse() {
ReadCoilsResponse response = null;
DigitalOut[] douts = null;
//1. get process image
ProcessImage procimg = ModbusCoupler.getReference().getProcessImage();
//2. get coil range
try {
douts = procimg.getDigitalOutRange(this.getReference(), this.getBitCount());
} catch (IllegalAddressException iaex) {
return createExceptionResponse(Modbus.ILLEGAL_ADDRESS_EXCEPTION);
}
response = new ReadCoilsResponse(douts.length);
//transfer header data
if (!isHeadless()) {
response.setTransactionID(this.getTransactionID());
response.setProtocolID(this.getProtocolID());
} else {
response.setHeadless();
}
response.setUnitID(this.getUnitID());
response.setFunctionCode(this.getFunctionCode());
for (int i = 0; i < douts.length; i++) {
response.setCoilStatus(i, douts[i].isSet());
}
return response;
}//createResponse
/**
* Sets the reference of the register to start reading
* from with this ReadCoilsRequest.
*
* @param ref the reference of the register
* to start reading from.
*/
public void setReference(int ref) {
m_Reference = ref;
//setChanged(true);
}//setReference
/**
* Returns the reference of the register to to start
* reading from with this ReadCoilsRequest.
*
* @return the reference of the register
* to start reading from as int.
*/
public int getReference() {
return m_Reference;
}//getReference
/**
* Sets the number of bits (i.e. coils) to be read with
* this ReadCoilsRequest.
*
* @param count the number of bits to be read.
*/
public void setBitCount(int count) {
if(count > Modbus.MAX_BITS) {
throw new IllegalArgumentException("Maximum bitcount exceeded.");
} else {
m_BitCount = count;
}
}//setBitCount
/**
* Returns the number of bits (i.e. coils) to be
* read with this ReadCoilsRequest.
*
* @return the number of bits to be read.
*/
public int getBitCount() {
return m_BitCount;
}//getBitCount
public void writeData(DataOutput dout)
throws IOException {
dout.writeShort(m_Reference);
dout.writeShort(m_BitCount);
}//writeData
public void readData(DataInput din)
throws IOException {
m_Reference = din.readUnsignedShort();
m_BitCount = din.readUnsignedShort();
}//readData
}//class ReadCoilsRequest