Very Basic Step Controller

novolts

Senior Member
Hi Guys

Below is a very basic program which suits my needs

On the site where I work there are 8 boilers

Some of the boilers lock out because they all try to fire up at the same time

So I am putting a time delay in between the boilers firing up to prevent boilers locking out

I am a qualified electrician so I know what precautions and I need to take

Using basic commands is it possible to condense the program code
Code:
main:
if pinC.2 = 1 then gosub Heaton
goto main ; else loop back to start 

Heaton:
high C.1   ;Boiler Number 1 on

pause 5000 ;wait 5 seconds

high C.0   ;Boiler Number 2 on

pause 5000 ;wait 5 seconds

high C.7   ;Boiler Number 3 on

pause 5000 ;wait 5 seconds

high C.6   ;Boiler Number 4 on

pause 5000 ;wait 5 seconds

high B.7   ;Boiler number 5 on

pause 5000 ;wait 5 seconds 

high B.6   ;Boiler number 6 on

pause 5000 ;wait 5 seconds
high B.5   ;Boiler number 7 on

pause 5000 ;wait 5 seconds

high B.4   ;Boiler number 8 on

pause 1000
  
low C.2

end
thanks for reading the post
novolts
 
Last edited by a moderator:

sghioto

Senior Member
You could use a "gosub delay" after "high C.1" and each time an output goes high. Still have the same number of lines of code though. Question, why are you changing input pin C.2 to an output with the line "low C.2" at the end of the program and how does the program no when to recycle after all 8 burners are on? There is no "return " command. Just asking.:confused: Also requires the "endif" command after "gosub Heaton"

Code:
[COLOR=#000000]main:[/COLOR]
[COLOR=#000000]if pinC.2 = 1 then 
gosub Heaton
[/COLOR]endif
[COLOR=#000000]goto main ; else loop back to start 

[/COLOR]Heaton:
high C.1
gosub delay
etc,
etc,
high B.4
pause 1000
low C.2
end


delay: pause 5000
       return

Steve G
 
Last edited:

techElder

Well-known member
I've been in lots of industrial businesses on repair jobs. I would hate to run across this gadget of yours. Personally, I would have disconnected it.

What you need is 8 or 10 industrial time delay relays set to different delay settings.

Your program needs lockouts and places to interrupt the sequence.

What happens when the power cycles and you aren't there?
 

hippy

Technical Support
Staff member
Using basic commands is it possible to condense the program code
This would save some 50%+ of program memory at the expense of using EEPROM -

Code:
Eeprom ( C.1, C.0, C.7, C.6, B.7, B.6, B.5, B.4 )
For b0 = 0 To 7
  Read b0, b1
  High b1
  Pause 5000
Next
 

novolts

Senior Member
Thanks Guys
Texasclodhopper
I fully take on board what you say but perhaps I have not made clear what I wish to do

I have 8 boilers that all try to come on at once and some lockout because of the drop in gas pressure

Each boiler has fuse protection

I am putting a delay in between the boilers firing up

Once the boilers fire up all safety devices will still operate

So if the boiler goes to overheat the overheat thermostat will activate
likewise lockout will operate if the flame is interrupted in anyway

The relays will be in series with the fuses

Kind regards
Novolts
 

jims

Senior Member
This would save some 50%+ of program memory at the expense of using EEPROM -

Code:
Eeprom ( C.1, C.0, C.7, C.6, B.7, B.6, B.5, B.4 )
For b0 = 0 To 7
  Read b0, b1
  High b1
  Pause 5000
Next
Hippy... I didn't realize that the PE6 EEPROM command would interpret C.1 as the pin number 9...etc. Should be useful in the future. Thank you, JimS
 

premelec

Senior Member
@novolts - I'm not quite following - there is a pressure drop if all boilers fire at once but NOT if they are running at the same time? Or you need to have only a few on at once... ? Sounds like a gas piping problem :)
 

novolts

Senior Member
Hi Premelec
Greetings from sunny Glasgow Scotland

I thank you for taking the time to reply to my post

I appreciate this is a forum for picaxe and I don't want to upset fellow members with questions other than programming
As I said previously I am a maintenance electrician recently I arrived on site and 5 boilers out of 8 had locked out
I reset the 5 boilers and immediately they all tried to fire up at once ( they are atmospheric boilers ) and locked out again

I reset the boilers one at a time I waited until boiler 5 fired up and then I reset boiler 6 and waited until that fired up and repeated the procedure for boilers ,7,8

The boilers ran the rest of the day with no further lockouts ,the boilers reached temp and switched off with the thermostat and fired back up when the temperature dropped
I had a fellow engineer check the standing gas pressure and it was satisfactory with no boilers on ,but when the 8 boilers tried to fire up at once the pressure dropped

The boilers are supposed to be staggered through software its a computerised system that was installed in a hurry a few years ago and has a few bugs that need to be resolved until the issues are resolved I would like to stagger the boilers firing up to prevent lockouts
I again apologise to any members whom I have bored with this post,however premelec took time to offer myself advise and I appreciate premlec feedback and the same for the other members who have replied to my previous posts on this matter
thanks to all
kindest regards
novolts
 

premelec

Senior Member
Thanks... I'm interested in control systems, plumbing and electronics :) It would be interesting to know what drops the pressure but as you say not very apropos to this forum... maybe a gas capacitor [that's a tank...] would solve the initial surge drop... anyhow good luck with it and thanks for the info. Post a picture of the humble PICAXE sequencing many big BTU boilers when you get it running well. And per Tex keep those safety circuits all working...
 

techElder

Well-known member
Novolts, for your gas pressure problem, do what you would do with a low voltage problem ... Get " bigger wire " or in this case add bigger pipe for the supply or add more pipes. I've seen things like that where they add boilers, but keep using the same supply lines.
 

novolts

Senior Member
Tex
there is absolutely no chance of that happening the person in charge of the boiler upgrade 7 years ago would not listen to the concerns of minds far superior to that of mine
he has since been promoted twice a still does not listen to advice
I don't want to appear rude Tex, as you have probably forgotten more than I will ever know but I don't want to use this forum for anything other than picaxe and I certainly don't want to upset senior members like your goodself
who I rely on for good sound advice
kind regards to all
novolts
 
Top