PLC Program

[L D[AR2P#0.0]]

Here's my crude implementation of CC's ladder logic from post #43. Run the exe and click on X0 and X1 to start the ball rolling.

Without some sort of visualisation, this will take for ever

 

[ceilingwalker]

Forgive me if someone else has asked this and I just missed it but, are you ramping and soaking to temp or are you 100% output until temp is reached? Also, are you using T/C's for temp reading/control?

 

[silva.foxx]

Forgive me if someone else has asked this and I just missed it but, are you ramping and soaking to temp or are you 100% output until temp is reached? Also, are you using T/C's for temp reading/control?

... this is only make-believe...


homework... if you like. But the guy is trying


@LD wrt post #43... agreed... it don't work... but how do you do that?

 

[silva.foxx]

@LD wrt post #43... agreed... it don't work... but how do you do that?

sorry... post #46


.

 

[silva.foxx]

We're up to 50 posts!!!

 door sw       

--] [----------]/[----------(m0)  Start Oven



  m0                        kt50

--] [-----------------------(t0)  Warning start time



  m0           

--] [----------]/[----------(m1)  Warning start on



  m0              

--] [----------] [----------(m2)  Heating



                            kt300

---------------] [----------(t1)  Heat time



  m0           

--] [----------] [----------(m3)  Heat complete



  m0           

--] [----------] [----------(m4)  Warning end



                            kt100

---------------] [----------(t2)  Warning end time



  m0           

--] [----------] [----------(m5)  Cooling



                            kt150

---------------] [----------(t3)  Cooling time



  m0                      

--] [----------] [---+------(m6)  End Oven

                     |

 door sw             |

--] [----------] [---+  



                 

------------] [----]/[------(y0)  Red lamp



                   

--] [--+-----------]/[------(y1)  Amber lamp

       |

       |

--] [--+



  

--] [-----------------------(y2)  Green lamp





                 

------------] [----]/[------(y3)  Heater On

You're going to have to fill in the blanks!

 

[OkiePC]

My opinion of what Chris needs for a breakthrough:

A) Build real hardwired circuits:
---Simple motor start stop station with a normally open PB, a normally closed PB and a motor starter (or relay).
---Forward and Reverse start stop station with same as above plus one more relay or motor starter and electrical interlocks.
---Two motor start stop station where motor 1 must run for five seconds before motor 2 starts.
---Add to above circuit a pressure switch (or another normally closed PB) that will stop both motors and reset the timer.
---Two motor circuit with start and stop buttons, motor 2 must start 10 seconds after motor 1 is running and must run for 30 seconds after motor 1 stops.

B) A real PLC and the above exercises.

Then the double coils and other logical misunderstandings will instantly vanish when you go from electrical motor controls to ladder logic, and building more and more complex programs will go much easier.

No offense to Chris if I have misjudged his skills and experience...I have seen this type of training make the "light bulb turn on " for many a mechanic or novice electrician who was totally or partially lost with PLC programming.

There is no substitute for trial and error with real working equipment in front of you, and learning how to hard-wire relay logic, especially timing relays, is very educational for someone starting out.

Paul

 

[leitmotif]

This has been in the back of my mind and only became apparent to me when Okie wrote it up.

I heartily endorse this kind of thinking and would paraphrase / condense thus
You must understand the whole system in order to understand how the controls are supposed to make the system work.

I second the recommendation

Dan Bentler

 

[L D[AR2P#0.0]]

@LD wrt post #43... agreed... it don't work... but how do you do that?

sorry... post #46


.

A few lines of code using Delphi. I expect a similar result can be achieved with Excel using VBA

procedure TForm1.Timer1Timer(Sender: TObject);
begin
//Rung 1
M3.Checked:=M3Coil.Checked;

M1Coil.Checked:= (X0.Checked or M3.Checked) and X1.Checked;

//Rung 2
M1.Checked:=M1Coil.Checked;

If T1Count > 0 then T1Count:=T1Count-1;
If M1.Checked and not T1RisingEdgeStore then T1Count:=500;
T1RisingEdgeStore:=M1.Checked;
T1Coil.Checked:= (T1Count>0);

//Rung 3
M1A.Checked:=M1.Checked;
M3A.Checked:=not M3.Checked;
M2C.Checked:=M2Coil.Checked;
T1.Checked:=not T1Coil.Checked;

M2Coil.Checked:= (M1Coil.Checked or (M2Coil.Checked and not M3Coil.Checked)) and not T1Coil.Checked;



//Rung 4
M2A.Checked:=M2Coil.Checked;

If T2Count > 0 then T2Count:=T2Count-1;
If M2Coil.Checked and not T2RisingEdgeStore then T2Count:=3000;
T2RisingEdgeStore:=M2Coil.Checked;
T2Coil.Checked:= (T2Count>0);

//Rung 5
M2B.Checked:=M2Coil.Checked;
M3B.Checked:=M3Coil.Checked;
T2.Checked:=T2Coil.Checked;

M3Coil.Checked:=(M2Coil.Checked or M3Coil.Checked) and T2Coil.Checked;

//Rung 6
M3C.Checked:=M3Coil.Checked;

If T3Count > 0 then T3Count:=T3Count-1;
If M3Coil.Checked and not T3RisingEdgeStore then T3Count:=1000;
T3RisingEdgeStore:=M3Coil.Checked;
T3Coil.Checked:= (T3Count>0);

//Rung 7
M3D.Checked:=M3Coil.Checked;
M4.Checked:=M4Coil.Checked;
T3.Checked:=T3Coil.Checked;

M4Coil.Checked:=(M3Coil.Checked or M4Coil.Checked) and T3Coil.Checked;

//Rung 8
M3.Checked:=M4Coil.Checked;

If T4Count > 0 then T4Count:=T4Count-1;
If M4Coil.Checked and not T4RisingEdgeStore then T4Count:=1500;
T4RisingEdgeStore:=M4Coil.Checked;
T4Coil.Checked:= (T4Count>0);

if M1Coil.Checked then Amber1.Color:=clYellow else Amber1.Color:=clBtnFace;
if M2Coil.Checked then Red.Color:=clRed else Red.Color:=clBtnFace;
if M3Coil.Checked then Amber2.Color:=clYellow else Amber2.Color:=clBtnFace;
if M4Coil.Checked then Green.Color:=clGreen else Green.Color:=clBtnFace;

T1Value.Caption:= inttostr(T1Count);
T2Value.Caption:= inttostr(T2Count);
T3Value.Caption:= inttostr(T3Count);
T4Value.Caption:= inttostr(T4Count);
end;

 

[L D[AR2P#0.0]]

Chris - do you have any programming experience with anything else ?

 

[Chris Corkhill]

Program

silva.foxx

I think I've exhausted your's and everyone else's patience, for that I apologise

As you can no doubt gather I've had no previous experience with PLC's or any other kind of programming. I was given this as an assignment to be handed in and demostrated on Tuesday coming complete with typical paperwork ie..instruction lists etc for the program.
Your help and guideance (and patience) has been great, and to all the guys & girl who have posted comments I say a big thank you !! I've had my head in books most of the week, and slowly it's becoming clearer, although I'm under no illusions I'm not the finished article yet by some way.

I've attemted to fill the blanks, I hope some of its correct, I'm working on the thought process of input = output.... maybe this is wrong ?

Thanks once again everybody, you have my upmost respect

 

[Chris Corkhill]

no, i have no previous experience.. this is really hard to grasp i'm finding

 

[leitmotif]

It's help I require not lesson in morality..

Chris I do not think I have seen anyone change their attitude so fast. Smart people are able to adapt so you should take this as a complement. The knowledge and ability you have gained in the last several days is also amazing.

Do I correctly assume this assignment if for a non PLC course?
What course is this for?
Dan Bentler

 

[silva.foxx]

Chris... you've not exhausted anyone's patience.

wrt your attempt to fill-in-the-blanks. You're almost there.
I've left in the correct bits. You've added a 'stop' input that the task description doesn't ask for. We'll come to that once you've completed the blanks...

 door sw         

--] [----------]/[----------(m0)  Start Oven



  m0                        kt50

--] [-----------------------(t0)  Warning start time



  m0           t0

--] [----------]/[----------(m1)  Warning start on



  m0                

--] [----------] [----------(m2)  Heating



               m2           kt300

---------------] [----------(t1)  Heat time



  m0           t1

--] [----------] [----------(m3)  Heat complete



  m0           m3

--] [----------] [----------(m4)  Warning end



               m4           kt100

---------------] [----------(t2)  Warning end time



  m0           t2

--] [----------] [----------(m5)  Cooling



               m5           kt150

---------------] [----------(t3)  Cooling time



  m0           t3           

--] [----------] [---+------(m6)  End Oven

                     |

 door sw             |

--] [----------] [---+  



            m2       

------------] [----]/[------(y0)  Red lamp



  m1                 

--] [--+-----------]/[------(y1)  Amber lamp

       |

       |

--] [--+



  m5

--] [-----------------------(Y2)  Green lamp





                     

------------] [----]/[------(y3)  Heater On

Attached is a Notepad file. Adapt it then copy and paste the contents into a post between the ladder tags (see -||- up top next to the highlighted ABC). Saves you printing out and scanning each time!

 

[Chris Corkhill]

leitmotif (Dan Butler)

You assume correct, the course I am studying is a Higher National Certificate (HNC) in Instrumentation & Process Control. PLC's is just one module of the course out of 10. We just have a 1 1/2 lecture a week and are often left to our own devices. Sort of teach yourself if you like. This website has been a huge help and you guys comments. Without it I'd have been stumped. Thanks all.

Chris

 

[Chris Corkhill]

 

door sw       

--] [----------]/[----------(m0)  Start Oven

  m0                        kt50

--] [-----------------------(t0)  Warning start time

  m0           t0

--] [----------]/[----------(m1)  Warning start on

  m0           t0  

--] [----------] [----------(m2)  Heating

               m2           kt300

---------------] [----------(t1)  Heat time

  m0           t1

--] [----------] [----------(m3)  Heat complete

  m0           m3

--] [----------] [----------(m4)  Warning end

               m4           kt100

---------------] [----------(t2)  Warning end time

  m0           t2

--] [----------] [----------(m5)  Cooling

               m5           kt150

---------------] [----------(t3)  Cooling time

  m0           t3           

--] [----------] [---+------(m6)  End Oven

                     |

 door sw             |

--] [----------] [---+  

            m2     t0 

------------] [----]/[------(y0)  Red lamp

  m1               t2

--] [--+-----------]/[------(y1)  Amber lamp

       |

   m4  |

--] [--+

  m5

--] [-----------------------(Y2)  Green lamp



             m2     t1 

------------] [----]/[------(y3)  Heater On