Tech Arsenal 1/Tech Arsenal (Arsenal Computer).ISO/tek-02/oop_tp55.zip/LIST5_A.PAS

Pascal/Delphi Source File | 1990-01-24 | 12KB | 485 lines

{ Unit: Tags

Utilization notes:

1. If no file name is supplied on the command line, the
   program will print output to the screen.  If a file
   name is supplied, the output will be directed to the
   file.

2. The object 'Quiet' controls program output
   (including the opening and closing of output files.)
   The procedure Quiet.On will turn output off and close
   the output file, if one is specified.  Subsequent calls
   to the procedure Quiet.Off will turn output back on and
   append it to f.  The default status of Quiet is ON.

3. Users wanting to write to a file must first
   make sure Quiet is Off, and direct output to
   the file f, as in the following example.

     if Quiet.IsOff then
         writeln( f, 'Put your string here' );

4. Programs using this unit should, at the end of the progam,
   either explicitly make a call to Quiet.On or include the
   line

       Close( f );
}

{ Specification for Tags class ***************************

  Variables:
            TagNumber : String12;
            Stores a tag number of up to 12 characters.

  Procedures:
            .Init(( ATag : String12 );
            ATag is stored in TagNumber.

  Descendant object types:
            Digital
            Analog              }

{ Specification for Digital class ************************

  Variables:
            Status : boolean;
            Indicates whether digital object is ON or OFF.
            ON denotes TRUE; OFF, FALSE.

  Procedures:
            .Init( ATag : String12; AStatus : boolean );
            ATag is stored in TagNumber; AStatus is stored
            in Status.

            .PutStatus( AStatus : boolean );
            Sets Status to AStatus.

  Functions:
            .GetStatus : boolean;
            Returns ON or OFF status of object.
            If variable 'Quiet' (boolean) is ON, then
            Status is not printed to screen; otherwise
            the Status and TagNumber are printed to
            the screen.

  Descendant object types:
            DInput
            DOutput          }

{ Specification for Analog class *************************
  Variables:
            Value : Resolution;
            Value must have a value between 0 and 4095.

            ZeroVal : real;
            Engineering unit value corresponding to a Value
            of 0.

            MaxVal : real;
            Engineering unit value corresponding to a Value
            of 4095.

            Slope : real;
            A number calculated from the equation:
   (MaxVal-ZeroVal)/(4095-0).

  Procedures:
            .Init(( ATag : String12; AValue : Resolution;
            Min, Max : real );
            Storage as follows:
   ATag -> TagNumber
   AValue -> Value
   Min -> ZeroVal
   Max -> MaxVal

            .PutValue( AValue : real );
            Converts AValue engineering units into counts
            (between 0 and 4095) and stores in Value.

  Functions:
            .GetValue : real;
            Converts and returns the counts in Value to
            engineering units.

  Descendant types:
            None.       }

{ Specification for DInput class *************************

  Variables:
            Setpoint : real;
            Contains a value at which something happens.

            Reading : real;
            Contains an number that is compared to the
            setpoint.

  Procedures:
            .PutSetpoint( NewSetpoint : real );
            Sets Setpoint to NewSetpoint.

            NOTE: .Init procedure is packaged with
     descendant classes.

  Descendant object types:
            HiSwitch
            LoSwitch         }

{ Specification for DOutput class ************************

    NO VARIABLES, NO PROCEDURES, NO FUNCTIONS
    (see descendant object type)

  Descendant object types:
            Pump        }

{ Specification for HiSwitch class ************************

  Procedures:
.Init(( ATag : string;
        ASetpoint : real;
        AReading : real);
Storage as follows:
  ATag -> TagNumber
  ASetpoint -> Setpoint
The value of AReading is stored in Reading
using the .PutReading method.

.PutReading( NewReading : real);
Store NewReading in Reading.  Set Status to
ON if Reading >= Setpoint.

  Descendant object types:
None.      }

{ Specification for LoSwitch class ************************

  Procedures:
.Init(( ATag : string;
        ASetpoint : real;
        AReading : real);
Storage as follows:
  ATag -> TagNumber
  ASetpoint -> Setpoint
The value of AReading is stored in Reading
using the .PutReading method.

.PutReading( NewReading : real);
Store NewReading in Reading.  Set Status to
ON if Reading <= Setpoint.

  Descendant object types:
None.      }

{ Specification for Pump class **************************

  Variables:
            FlowRate : real;
            A number representing gpm flow when pump is
            ON.  NOTE: THIS IS A *VERY* ROUGH APPROXIMATION
            OF PUMP BEHAVIOR!

  Procedures:
            .Init( ATag : String12; AStatus : boolean;
      AFlow : real );
            Storage as follows:
  ATag -> TagNumber
  AStatus -> Status
  AFlow -> FlowRate

  Functions:
            .Flow : real;
            Returns the value stored in FlowRate.

  Descendant object types:
            None.       }

unit Tags;

interface

uses Crt; { for KeyPressed }

const

ON  = true;
OFF = false;
MinR = 0;       { Minimum number of counts in an analog
input }
MaxR = 4095;    { Maximum number of counts in an analog
input }

var
    f : text;  {predefined file type}

type

Resolution = 0..4095;  { Range for analog input }
String12 = string[12];


Tag = object
      TagNumber : String12;
      procedure Init( ATag : String12 );
      end;

Digital = object(Tag)
          Status : boolean;
          procedure Init( ATag : String12; AStatus :
boolean );
          procedure PutStatus( AStatus : boolean );
          function GetStatus : boolean;
          end;

Analog = object(Tag)
         Value : Resolution;
         ZeroVal : real;
         MaxVal : real;
         Slope  : real;
         procedure Init( ATag : String12; AValue :
Resolution;
            Min, Max : real );
         procedure PutValue( AValue : real );
         function GetValue : real;
         end;

DOutput = object(Digital)
          end;

Pump = object(DOutput)
       FlowRate : real;
       procedure Init( ATag : String12; AStatus : boolean;
                       AFlow : real );
       function Flow : real;
       end;


DInput = object(Digital)
            Setpoint  : real;
            Reading   : real;
            procedure PutSetpoint( NewSetpoint : real );
            end;

HiSwitch = object(DInput)
           procedure Init( ATag : string;
            ASetpoint : real;
            AReading : real);
           procedure PutReading( NewReading : real );
           end;

LoSwitch = object(DInput)
           procedure Init( ATag : string;
            ASetpoint : real;
            AReading : real);
           procedure PutReading( NewReading : real );
           end;

FSwitch = object
          State : boolean;
          procedure Init( InitState : boolean );
          procedure On;
          procedure Off;
          function IsOn : boolean;
          function IsOff : boolean;
          end;


function HtToPSI( Height : real ) : real;

function FlowToDeltaHt( Flow : real ) : real;

var
   Quiet : FSwitch;

implementation

procedure Tag.Init( ATag : String12 );
begin
     TagNumber := ATag;
end;

procedure Digital.Init( ATag : String12; AStatus : boolean
);
begin
     Tag.Init( ATag );
     Status := AStatus;
end;

procedure Digital.PutStatus( AStatus : boolean );
begin
     Status := AStatus;
end;

function Digital.GetStatus : boolean;
begin
     if (Status = ON) and (Quiet.IsOff) then
        writeln( f, TagNumber, ' is ON.' )
     else
        if (Quiet.IsOff) then
           writeln( f, TagNumber, ' is OFF.' );
     GetStatus := Status;
end;

procedure Pump.Init( ATag : String12; AStatus : boolean;
AFlow : real );
begin
     Digital.Init( ATag, AStatus );
     FlowRate := AFlow;
end;

function Pump.Flow : real;
begin
     Flow := FlowRate;
end;

procedure Analog.Init( ATag : String12;
          AValue : Resolution;
          Min, Max : real );
begin
     Tag.Init( ATag );
     Value := AValue;
     MaxVal := Max;
     ZeroVal := Min;
     Slope := (Max-Min)/(MaxR-MinR);
end;

procedure Analog.PutValue( AValue : real );
begin
     if AValue > MaxVal then
        AVAlue := MaxVal
     else
        if AValue < ZeroVal then
           AValue := ZeroVal;
     Value := Round((AValue - ZeroVal)/Slope);
end;

function Analog.GetValue : real;
begin
     GetValue := Slope*Value + ZeroVal;
end;

procedure DInput.PutSetpoint( NewSetpoint : real );
begin
     Setpoint := NewSetpoint;
end;

procedure LoSwitch.Init( ATag : string;
            ASetpoint : real;
            AReading : real);
begin
     Tag.Init( ATag );
     DInput.PutSetpoint( ASetpoint );
     PutReading( AReading );
end;

procedure LoSwitch.PutReading( NewReading : real );
begin
     Reading := NewReading;
     if Reading <= Setpoint then
        Status := true
     else
        Status := false;
end;

procedure HiSwitch.Init( ATag : string;
            ASetpoint : real;
            AReading : real);
begin
     Tag.Init( ATag );
     DInput.PutSetpoint( ASetpoint );
     PutReading( AReading );
end;

procedure HiSwitch.PutReading( NewReading : real );
begin
     Reading := NewReading;
     if Reading >= Setpoint then
        Status := true
     else
        Status := false;
end;

procedure FSwitch.Init( InitState : boolean );
begin
     State := InitState;
     if State = false then  { If we want output}
        Rewrite( f )      { Open file f }
     else
        begin
        Rewrite( f );     { Open file f }
        Close( f );       { and close it }
        end;
end;

procedure FSwitch.On;
begin
     if State = false then
        begin
        State := true;
        Close( f );
        end;
end;

procedure FSwitch.Off;
begin
     if State = true then
        begin
        State := false;
        Append( f );
        end;
end;

function FSwitch.IsOn : boolean;
begin
     if State = true then
        IsOn := true
     else
        IsOn := false;
end;

function FSwitch.Isoff : boolean;
begin
     IsOff := not IsOn;
end;

{ HtToPSI converts a height (of a column of water) into a
pressure.
  The math is pretty simple:  A column of water 2.31 feet
high exerts
  a force of one pound per square inch at the bottom. }

function HtToPSI( Height : real ) : real;
begin
     HtToPSI := Height/2.31;
end;

{ FlowToDeltaHt converts a flow into (or out of) our system
into a
  change in height in the tank.
  The math is as follows:  Divide the flow, in gpm, by 7.48
gal/cu.ft.
  to get the number of cubic feet pumped per minute.
Divide this
  number by the volume of 1 vertical foot of the tank,
which is
  the radius squared times 'pi' (15*15*3.1416). }

function FlowToDeltaHt( Flow : real ) : real;
begin
     FlowToDeltaHt := Flow/(7.48 * 706) ;
end;

{ initialization code }
begin

Assign( f, ParamStr(1) );

Quiet.Init(OFF);

end.

{ Listing 3-1 }