Timer Questions

Archiver

I'm used to PLC programming where you can use delay on or off timers
while the rest of the code is still executing, with the stamp and the
pause command everything stops, is there any way to run a timer while
code is still being executed, or would I have to use a external timer
like a 555 or 556 ?? Also could I use a real time clock to cause
daily events?? Thanks.

Archiver

You could use a 555 or a real time clock (RTC) module. There is an
application note on the Parallax web site about using the DS1302
RTC. The problem with both of those solutions is that the basic
stamp can't handle interupts so your code will have to poll either
the timer or the RTC.

--- In basicstamps@yahoogroups.com, "todd22827" <todd@s...> wrote:
> I'm used to PLC programming where you can use delay on or off
timers
> while the rest of the code is still executing, with the stamp and
the
> pause command everything stops, is there any way to run a timer
while
> code is still being executed, or would I have to use a external
timer
> like a 555 or 556 ?? Also could I use a real time clock to cause
> daily events?? Thanks.

Archiver

RTCs are easy to connnect and will give you infinitely more flexibility in
your projects. Our web site has code for at least two (DS1302, PCF8583).

-- Jon Williams
-- Parallax


In a message dated 6/1/2003 12:32:00 PM Central Standard Time,
todd@s... writes:

> I'm used to PLC programming where you can use delay on or off timers
> while the rest of the code is still executing, with the stamp and the
> pause command everything stops, is there any way to run a timer while
> code is still being executed, or would I have to use a external timer
> like a 555 or 556 ?? Also could I use a real time clock to cause
> daily events?? Thanks.



[noparse][[/noparse]Non-text portions of this message have been removed]

Archiver

Hi Todd,

I use PLC's too, but I like Stamps better.
The PLC timers are nice though.

When I need a delay instead of doing a pause xxxx
I will pause for 1 count, go look at the other things that need looking at
and then come back the delay.

This code waits for a process delay, while looking at two status inputs. If
the inputs change the program jumps. If not a small delay happens, and starts
over again.

x = 0
'PDD = a user delay setting
Man_Fire_1:
'
if Plasma_Start = 1 then Plasma_Off 'Look for the start command to go
away
if Motion_In = 1 then Man_Fire_1 'Look for Machine Motion to go away
X=X+1 'Wait for Pierce Delay
pause 1
if x < PDD then Man_Fire_1

Next_Code_Section:

This code is used for starting a Plasma Cutting Torch
I look at the 2 signals (Plasma-Start & Motion_In)
If they are still true then I
Pause 1
Increment the counter
Test the counter to see if it has counted up high enough.
If it has then it drops to the next code section.
If not then it goes to the start of the section and checks
everything again.

This is crude timing but for things under a few seconds it is quite accurate.
You can fine tune the value of PDD for better accuracy if needed.

With this code you can watch stuff and wait at the same time.
I like to call it Waiting Faster.

Hope this helps.

Alan Bradford
Plasma Technologies





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