PID-filter routine (2nd try).

[andywpg]

If anyone is interested, here is what I used to run the simulation (my controller has an LCD)

#CONFIG
 __config _CONFIG1, _INTRC_OSC_NOCLKOUT & _WDT_OFF & _MCLRE_OFF & _LVP_OFF & _CP_OFF 
#ENDCONFIG

DEFINE OSC 8  'LETS PBP KNOW THE OSCILLATOR IS RUNNING AT 8MHz
DEFINE NO_CLEARWDT 1 'NO WATCHDOG TIMER - FOR NOW - WILL DO OUR OWN CLRWDT


OSCCON = %01110001 '8 MHz INTERNAL OSCILLATOR, INTERNAL OSCILLATOR IS USED FOR SYSTEM CLOCK


DISABLE 'NO PBP INTERRUPTS NO PBP DEBUG

' Set LCD Data port
DEFINE LCD_DREG PORTB
' Set starting Data bit (0 or 4) if 4-bit bus
DEFINE LCD_DBIT 0
' Set LCD Register Select port
DEFINE LCD_RSREG PORTB
' Set LCD Register Select bit
DEFINE LCD_RSBIT 4
' Set LCD Enable port
DEFINE LCD_EREG PORTB
' Set LCD Enable bit
DEFINE LCD_EBIT 5
' Set LCD bus size (4 or 8 bits)
DEFINE LCD_BITS 4
' Set number of lines on LCD
DEFINE LCD_LINES 2
' Set command delay time in us
DEFINE LCD_COMMANDUS 1500
' Set data delay time in us
DEFINE LCD_DATAUS 44



  '// Set up hardware registers, ADC etc here (not shown) //

  ADValue VAR WORD                     '<---This is your variable.
  SetPoint VAR WORD                    '<---This is your variable.
  COUNTER VAR BYTE
  RUN_IND VAR BYTE




  INCLUDE "incPID.pbp"                 'Include the PID routine.

    'These variables are declared by the incPID routine but
    'the user needs to assign values to them.
    pid_Kp = $0700                     'Set Kp to 7.0 GAIN
    pid_Ki = $0080                     'Set Ki to 0.5 RESET
    pid_Kd = $0001                     'Set Kd to 0 (Derivative not necessary)
    pid_Ti = 8                         'Update I-term every 8th call to PID
    pid_I_Clamp = 100                  'Clamp I-term to max ±100
    pid_Out_Clamp = 255                'Clamp the final output to 0 to 255
	Setpoint = 230		               '<---Set desired position.
	RUN_IND = 1

START:
   	FOR ADVALUE = 225 TO 235 'TEST A BUNCH OF VALUES
		FOR COUNTER = 1 TO 10
   			pid_Error = Setpoint - ADValue     'Calculate the error
			Gosub PID                          'Result returned in pid_Drive
   			if pid_Out.15 then pid_out = 0     'IF NEGATIVE THEN SHUT OFF FAN
   			pid_Out = ABS pid_Out              'Convert from two's comp. to absolute
'  			HPWM 1, pid_Out, 10000             'Set PWM output

			LCDOUT $FE, 1, "AD=", DEC ADVALUE, " PO=", SDEC PID_OUT
			LCDOUT $FE, $C0, "RUN #", DEC COUNTER, " SETP ", DEC SETPOINT
			Pause 1000                           'Wait....
		NEXT COUNTER
	NEXT ADVALUE
	IF RUN_IND = 1 THEN
		RUN_IND = 0 
		GOTO START 'DO IT AGAIN SO THAT ITS AS IF THE TEMPERATURE DROPPED 
	ENDIF
	LCDOUT $FE, 1, "DONE!"
	DO
	LOOP 'ENDLESS LOOP
	
END