Dimmer

[HenrikOlsson]

Reven,
I've not used that circuit or code you are reffering to but by just looking at your waveforms it seems that the triac is triggered at the same phase angle in case 1, 2, 3 & 4.

The triac only needs a short pulse on the gate and will then hold itself 'on' untill the AC-line crosses zero, at which point it will turn 'off'. That short pulse should be delayed a certain amount of time from the zero crossing.

On your scope pics the triac seems to be triggered exactly 1div from the zero crossing in all cases except full on and full off.

/Henrik Olsson.

[Acetronics2]

Hi, reven

Henrik is right ...

Here, the pulse length is not the thing to be variable.

but you must vary the time between zero voltage detection and triac gate firing ...

Long time = weak light
short time = full light

remember once the triac is turned on it stays turned ON until current becomes null.


Alain

Here, you had programmed a ... DC Dimmer !!!

[Reven]

I think you have right...
As Henrik says ,now the triac is triggered at the same phase angle in all cases.
I must change my code to put the pulse position in a variable.
Thanks all of you!
I will inform you about my progress!




BTW, take a look at the code,bacause I checked it many times and I could not find where the problem is.

http://www.picbasic.co.uk/forum/atta...0&d=1103787743

Thanks again,
Reven

[Acetronics2]

Hi, Reven

Just understand what the interrupt routine does instead of should have done ...

""
' ACDetect
' --------
'
' Interrupt routine called by ACLine (GP4) pin state change
'
disable
ACDetect:
if ACline==1 then ' Check for rising edge of AC signal
if triacdelay > 0 then
Triac=1 ' Activate TRIAC

Alain's : ;;; No,No,No ... here we have to wait for ( Maxdelay - Triacdelay ) !!! THEN fire the Triac for, say, 20µs ... then let things quiet.

if FullBright==0 then ' In case Brightness flag is not set
pauseus triacdelay ' do the selected delay
triac=0 ' Disable TRIAC
endif
else
triac=0
endif
endif
INTCON.0=0 ' Clear GPIF (interrupt on GP4 change)
resume
enable

""


*** This part of program smells to have been taken from a heather using burst mode dimming ...

Sorry, Steve ... je t'aimais bien ( avec la musique de circonstance ... )

Alain

[mister_e]

mmm, sorry all. something should be wrong in what i posted. I used that program in various app and it worked... let me the time to return at home(Next week) and i'll compare the posted version and what i use...

Many thousands of appologies.

[mister_e]

Can't wait to return home... use the following ACDetect routine instead.
this should work.

disable
ACDetect:
if ACline==1 then 
    '
    '    Rising edge of AC signal
    '    ========================
	if triacdelay then              ' A delay is set by user
                                        '  
	    if FullBright==0 then       ' Full Brightness flag is not set
            pauseus maxdelay-triacdelay '    do the selected delay
            triac=1                     '    enable TRIAC	    	
            else                        '
    	        triac=1                 ' Full Brightness flag is set
                                        '    enable triac
            endif                       '
                                        '
        else                            '
    	    triac=0                     ' No Delay set by user... disable Triac
        endif                           '
    
    else                                
    '
    '    Falling edge of AC signal
    '    =========================
        if fullbright==0 then triac=0   ' Disable the Triac on falling edge of 
                                        ' Ac signal
    endif
INTCON.0=0 ' Clear GPIF (interrupt on GP4 change)
resume
enable

Yeah i know you can also use Pulsout and forget the Falling edge detection... as you wish. Both will work.

[Reven]

First, I write something like this:

' Interrupt routine called by ACLine (GP4) pin state change
disable
ACDetect:

if ACline=1 then ' Check for rising edge of AC signal

pauseus triacdelay ' do the selected delay
Triac=1 ' Activate TRIAC
pauseus 20
Triac=0 ' Disable TRIAC

endif


INTCON.0=0 ' Clear GPIF (interrupt on GP4 change)
resume
enable



and because I use half wave signal from the AC line on GP4, finaly something like this:


' Interrupt routine called by ACLine (GP4) pin state change
disable
ACDetect:

if ACline=1 then ' Check for rising edge of AC signal

pauseus triacdelay ' do the selected delay
Triac=1 ' Activate TRIAC
pauseus 20
Triac=0 ' Disable TRIAC


'send a second pulse to triac,after 10ms, like the full wave
pause 10
Triac=1 ' Activate TRIAC
pauseus 20
Triac=0 ' Disable TRIAC


endif


INTCON.0=0 ' Clear GPIF (interrupt on GP4 change)
resume
enable





Again, thanks all of you!
Reven

[FromTheCockpit]

Can't wait to return home... use the following ACDetect routine instead.
this should work.

disable
ACDetect:
if ACline==1 then 
    '
    '    Rising edge of AC signal
    '    ========================
	if triacdelay then              ' A delay is set by user
                                        '  
	    if FullBright==0 then       ' Full Brightness flag is not set
            pauseus maxdelay-triacdelay '    do the selected delay
            triac=1                     '    enable TRIAC	    	
            else                        '
    	        triac=1                 ' Full Brightness flag is set
                                        '    enable triac
            endif                       '
                                        '
        else                            '
    	    triac=0                     ' No Delay set by user... disable Triac
        endif                           '
    
    else                                
    '
    '    Falling edge of AC signal
    '    =========================
        if fullbright==0 then triac=0   ' Disable the Triac on falling edge of 
                                        ' Ac signal
    endif
INTCON.0=0 ' Clear GPIF (interrupt on GP4 change)
resume
enable

Yeah i know you can also use Pulsout and forget the Falling edge detection... as you wish. Both will work.

Very interesting thread I must say. I am trying to do the same and have added DT_INTERRUPTS to manage the ac detect....But my lamp is not dimming at all, also when in the code 'triacdelay=0', my lamp does not go off........ Can someone spot the error please.

INCLUDE "DT_INTS-14.bas"     ; Base Interrupt System
INCLUDE "ReEnterPBP.bas"     ; Include if using PBP interrupts
Include "modedefs.bas"
@ __Config _XT_OSC & _WDT_ON & _PWRTE_ON & _MCLRE_OFF & _BODEN & _CP & _CPD

TriacDelay                  var Word
maxdelay                    var word

Triac	var	PortA.1 ' Output to TRIAC gate
ACLine	var	PortA.2 ' Input for the FullWave rectify AC line
Buz		var PortC.2

TRISA = %001100
TRISC = 0
CMCON = 7
ANSEL = 0
OPTION_REG = %11000000  ' RAPU = off, PS WDT
PORTA=0
PORTC=0

ASM
INT_LIST  macro    ; IntSource,        Label,  Type, ResetFlag?
        INT_Handler    INT_INT,  _ACDetect,   PBP,  yes
    endm
    INT_CREATE               ; Creates the interrupt processor
ENDASM

@   INT_ENABLE   INT_INT     ; enable external (INT) interrupts

Triac=0            ' disable Triac Gate
triacdelay=0  ' Set delay to minimum

while 1

pause 3000
high buz: pause 500 : low buz
triacdelay=8000     : pause 10000 :high buz: pause 50 : low buz 
triacdelay=5000     : pause 10000 :high buz: pause 50 : low buz 
triacdelay=4500     : pause 10000 :high buz: pause 50 : low buz 
triacdelay=4000     : pause 10000 :high buz: pause 50 : low buz
triacdelay=3500     : pause 10000 :high buz: pause 50 : low buz
triacdelay=0 : pause 7000

wend

ACDetect:
	if triacdelay > 0 then
			if triacdelay=8000 then
				triac=1 ' Activate TRIAC
			else
				maxdelay=8000-triacdelay
				pauseus maxdelay
				triac=1
				pauseus 50
				triac=0
   	     	endif
    else
 		     triac=0
    endif
@ INT_RETURN

P.S. I am using full wave with few high value resistance connected to phase and zeners to drop the voltage further.