Delay problem

[lloyd778]

Hi all, my first post on this great site, so be gentle with me...
I need to embed a program in the Olimex PIC I/O board. It has 4 Inputs and 4 relay Outputs. I am using a 16F628A. Using PBP. I use several of these boards in my little welding shop and always seem to have the same problem with Basic language programming. The relay response time when the input changes state is affected by the Pause command. I want to turn on a vacuum, pause, turn on a light, pause, turn on a power feed, pause, turn on a saw. I flip the switch on -vac comes on followed by the other relays OK. But there is that darned delay of up to 3 seconds at the beginning of each cycle. When the switch is turned off the saw MUST shut down immediately. But there is that darned delay again. The more Pause I include in the program the more delay I get at the beginning of each cycle. I can program the same hardware in Ladder Logic and not get the delay but I want to use PBP. Please tell me what the fix is. It's usually simple, I know, but 6 Saturdays have been invested with little result.
My latest (cleaned up) incantation:

pause 50
define OSC 20
CMCON = 7 ' digital I/O
TRISA = %00010000
TRISB = %00111001

counter var word

loop:
toggle portb.5 'Cycle on/off Power-On LED
if portb.0 = 1 then 'Switch is Off
gosub sub1
else
portb.0 = 0 'Switch is On
gosub sub2
endif
goto loop
sub1:
low 11 'Turn Off SAW immediately
gosub delay
low 10 'Turn Off power feed
gosub delay
low 9 'Turn Off Light
gosub delay
low 8 'Turn Off Vacuum
goto loop
sub2:
high 8 'Turn On Vacuum
gosub delay
high 9 'Turn On Light
gosub delay
high 10 'Turn On Power Feed
gosub delay
high 11 'Turn On SAW
goto loop

delay:
counter=32
repeat
pause 50
counter=counter-1
until counter=0
return

end

As I said, this works, but when I flip the switch off I really need the saw to stop immediately. Thanks to all of you. lloyd778

[Melanie]

Well isn't the important part NOT to have any delays?

loop:
	if portb.0 = 1 then	' Switch is OFF
		gosub sub2 
		else		' otherwise it's ON
		gosub sub1
		endif
	Goto Loop

sub1:
	low 11	 		' Turn Off SAW immediately
	low 10 			' Turn Off power feed
	low 9 			' Turn Off Light
	low 8 			' Turn Off Vacuum
	Return

sub2:
	high 8	 		' Turn On Vacuum
	high 9 			' Turn On Light
	high 10 		' Turn On Power Feed
	high 11 		' Turn On SAW
	Return

end

And if you want a blinky Light as well (which now introduces a maximum 10mS delay in this example)...

	counter=0
loop:
	if portb.0 = 1 then	' Switch is OFF
		gosub sub2 
		else		' otherwise it's ON
		gosub sub1
		endif
	counter=counter+1
	If Counter=>100 then
				' approx 1 second toggle
		toggle portb.5
		Counter=0
		endif
	Pause 10
Goto Loop

sub1:
	low 11	 		' Turn Off SAW immediately
	low 10 			' Turn Off power feed
	low 9 			' Turn Off Light
	low 8 			' Turn Off Vacuum
	Return

sub2:
	high 8	 		' Turn On Vacuum
	high 9 			' Turn On Light
	high 10 		' Turn On Power Feed
	high 11 		' Turn On SAW
	Return

end

Why not also ALIAS your Ports, so they're easier to program... at the start you declare your aliases...

LED var PortB.5

then in your program you can write Toggle LED instead of Toggle PortB.5

The bonus is, if you then decide to move the LED to a different port/pin, you make your change on ONE line of your program, and hey-presto, it doesn't matter how many times you've used LED, they all get reassigned.

Likewise alias, VACUUM, POWERFEED, LIGHT and SAW and you can then go...

Low SAW
Low POWERFEED
Low LIGHT
Low VACUUM

which makes fare more easier program understanding...

[lloyd778]

Thank you for your reply. I do need the delays. If I turn on all the tools at once I will blow a fuse. I need the vac to stay on a few seconds after the saw shuts down to collect the dust. The blinky light just lets me know that it's getting power and to remind me of the hot mains connected to the relays(and lately I've been using it to see the cycle time). Blinky light is not so important but a few one second pauses without the latency would be so nice. How can I get a pause in the main program without the delay at the beginning of the cycle?

[lloyd778]

I organized it up a bit. The blinky no worky, so I went back to the simple toggle. I aliased everything that I could. Looks better but works the same. Any suggestions?


'* Name : relay4.BAS
'* Author : lloyd778
'* Notice : Copyleft
'* : No Rights Reserved
'* Date : 7/12/2006
'* Version : 1.0.25(+/-)
'* Notes : for Olimex 4 relay board (PIC I/O) 16F628A
'* Relay board incantation #25 at least
' Use of chicken bones and water buffalo entrails show no
' substantial improvement so far.

pause 50
define OSC 20
CMCON = 7 ' digital I/O
TRISA = %00010000
TRISB = %00111001
LED var portb.5
Saw var porta.3
Light var porta.1
Feed var porta.2
Vac var porta.0
Switch var portb.0
counter var byte
counter1 var byte

loop:
toggle led 'Power LED shows cycle time
if switch = 1 then ' Switch is OFF
gosub sub1
else 'otherwise it's ON
gosub sub2
endif

Goto Loop
sub1:
low saw
gosub delay
low feed
gosub delay
low light
gosub delay
low vac
goto loop
sub2:
high vac
gosub delay
high light
gosub delay
high feed
gosub delay
high saw
goto loop

delay:
counter=32
repeat
pause 50
counter=counter-1
until counter=0
return

end

[Melanie]

So you put your delays in the turn-on and NOT in the turn-off routines. You won't blow a fuse switching OFF.

btw... your code is shot! If you call a GOSUB then you terminate the subroutine with a RETURN (see my example), you don't exit back with a GOTO.

All that happens is you fill up your stack with unpredictable results.

[niels]

I organized it up a bit. The blinky no worky, so I went back to the simple toggle. I aliased everything that I could. Looks better but works the same. Any suggestions?

Your problem is in Sub2. The delays you are using are preventing the switch from being read. What you want to do is check the status of the switch inside the delay routine. If you see the switch go off, jump to Sub1. You need to keep checking the status of the switch - and the easiest place to do this is inside the delay routine itself.

[lloyd778]

Yes, that was exactly my problem all along. Thank you niels.

[Archangel]

' Use of chicken bones and water buffalo entrails show no
' substantial improvement so far.

You needed BLACK CAT BONES, and some HIGH JOHN THE CONQUERS ROOT AS WELL! OH AND A CHICKEN FOOT TOO! In liew of actual working code.

As a woodworker I say; Good Idea ! :-)

Edit: in retrospect, I think this device should be configured as a slave to the power tools magnetic power switch, Darn those sharp cutters, I think I would not trust a PIC with my fingers!

[niels]

I would not trust a PIC with my fingers!

I'd trust a PIC- the real question is would you trust the code. A big red mechanical 'kill-power' button in series with the saw wouldn't be a bad idea.