Michael T Flanagan's Java Scientific Library: Digital to analog converter model

Michael Thomas Flanagan's Java Scientific Library

DtoA Class: Modelling a Digital to Analogue Converter (DAC) for Control Theory Simulations

Last update: 8 November 2009 Main Page of Michael Thomas Flanagan's Java Scientific Library

This class contains the constructor to create an instance of a Digital to Analogue Converter and the methods to use this in control simulations.
An instance may be created that:
i. simulates a digital to analogue converter (DAC) of a given bit length and reference voltage. Three input types area allowed:

a binary number (as two's complement with sign extension) corresponding to the bit pattern in the output channels;
a decimal representation of the binary number;
a voltage value equal to the digital voltage.

or

ii. simply acts as a marker of a digital to analogue conversion in which the output equals the input voltage with no checks on the value. This can be useful in some control loop simulations.

This class is a subclass of the superclass BlackBox thus allowing easy use with classes such as OpenPath and ClosedLoop. Though many of the Blackbox methods are of limited relevance they will function. The s-domain transfer function will appear as the output voltage divided by the voltage equivalent of the input modified by any dead-time that may have been set.

import directive: import flanagan.control.DtoA;

Summary table of constructors and methods
Details of constructors and methods
Java source file (Last update: 8 November 2009)
Other Control Engineering Java classes
Other classes, in this library, used by this class
Main page of Michael T Flanagan Java Library

SUMMARY OF CONSTRUCTORS AND METHODS

Constructors		public DtoA(int nBits, double vRef)
Constructors		public DtoA()
Set Input		public void setInput(String input) public void setInput(int[ ] input) public void setInput(long input) public void setInput(double input)
Get input values	Binary input	public String getBinaryInput() public int[ ] getBinaryArray()
Get input values	Decimal input	public long getDecimalInput()
Output	Get voltage output	public double getOutput()
Return reference voltage	as voltage	public double getVref()
Return reference voltage	as decimal (binary)	public long getMaximumDecimal()
Settings	True DAC option	public boolean getTrueDtoAoption()
Dead Time (transportation time) [inherited from BlackBox]	Set the dead time	public void setDeadtime(double deadTime)
	Set the dead time	public void setDeadtime(double deadTime, double padeOrder)
	Get the dead time	public double getDeadtime()
	Set the Pade order	public void setPadeOrder(double padeorder)
	Get the Pade order	public void setPadeOrder(double padeorder)
See BlackBox for the remaining inherited methods

CONSTRUCTORS

public DtoA(int nBits, double vRef)
public DtoA()
Usage: DtoA dac = new DtoA(nBits, vRef);
This constructor creates a new instance of DtoA that simulates an n bit digital to analogue converter (DAC) of reference voltage, vRef. The number of bits, n, is passed to the constructor as the int variable, nBits.

public DtoA()
Usage: DtoA dac = new DtoA();
This constructor simply acts as a marker to be used in OpenPath and ClosedLoop to indicate the presence of an DAC. In this case there is no simulation of an DAC and the output is equal to the input plus any delay set.

SET THE INPUT

public void setInput(String input)
public void setInput(int[ ] input)
public void setInput(long input)
public void setInput(double input)
Usage: dac.setInput(input);
The method by which the input is entered.
The input may be represenred as:

A binary number in the form of a String of '0's and '1's.
If the String has a length equal to the DAC number of bits plus one the leading character is the sign bit
If the length of the String is less than the DAC number of bits plus one it will be assumed to be a positive binary.
If the length of the String is greater than the DAC number of bits plus one an error message will be returned.
A binary number in the form of an int array of '0's and '1's with the zeroth element of the array representing the least significant bit (LSB).
If the int array has a length equal to the DAC number of bits plus one the last array element is the sign bit
If the length of the int array is less than the DAC number of bits plus one it will be assumed to be a positive binary.
If the length of the int array is greater than the DAC number of bits plus one an error message will be returned.
A decimal equivalent of the binary input (as a long). An error message is returned if its absolute value is greater than the maximum decimal number the DAC';s number of bits will accommodate.
A voltage (as a double).
If the DtoA instance is a true simulation (see Constructor) this is treated as a voltage equivalent of the binary input ans is checked for range as above.
If the DtoA instance is simply a D to A marker (see Constructor) the output voltage is set equal to this oinput voltage without any checks.

GET THE INPUT VALUES

BINARY INPUT
public String getBinaryInput()
public int[ ] getBinaryArray()
Usage:                      binaryIn = dac.getBinaryInput();
Returns a String containing a binary representation of the input of the simulated DAC in a two's complement with a one bit sign extension format.

Usage:                      binaryArray = dac.getBinaryArray();
Returns an int array containing a binary representation of the intput of the simulated DAC in a two's complement with a one bit sign extension format. The least significant bit (LSB) is the zeroth array element.

DECIMAL INPUT
public long getDecimalInput()
Usage:                      decimalIn = dac.getDecimalInput();
Returns a decimal representation of the binary input of the simulated DAC.

OUTPUT

public double getOutput()
Usage: output = dac.getOutput();
Returns the output voltage, as a double, in volts

REFERENCE VOLTAGE

RETURN VALUE AS A VOLTAGE
public double getVref()
Usage: vRef = dac.getVref();
Returns the reference voltage as a voltage.

RETURN VALUE AS A BINARY (DECIMAL REPRESENTATION)
public double getMaximumDecimal()
Usage: vDec = dac.getMaximumDecimal();
Returns the reference voltage as the decimal representation of the maximum binary number that the DAC can output.

SETTINGS

TRUE DAC OPTION
public boolean getTrueDtoAoption()
Usage: option = dac.getTrueDtoAoption();

true is returned if the instance of DtoA is set as a true DAC simulation
false is returned if the instance of DtoA is simply a marker for use in OpenLoop or ClosedLoop

OTHER CLASSES USED BY THIS CLASS

This class is a subclass of BlackBox which uses the following classes in this library:

This page was prepared by Dr Michael Thomas Flanagan