A plea for help...and mentor

[mordred]

Wth regards to Rons earlier post concerning the destinations being the same you can easily set SQO n12:10's destination top O:0.1
SQO n12:20 to O:0.2
SQO n12:30 to O:0.3
however you should only have to set n12:20 and n12:30 to O:0.1
this should allow you to run both systems independantly. as it was the n12:20 and n12:30 destinations was overwriting the destination address on n12:0 and n12:1
you will also need to clear destination O:0.1
this is done for destination O:0.0 on rung 000 ladder 2,

 

[Ron Beaufort]

Greetings Damian,

maybe this is something that you don’t want to hear ... but ... are you SURE that you want to stick with the SQO (sequencer) idea for your program? ... before you answer, you might want to take a look at this post in a recent thread ... the problem centered around an existing program which used an SQO instruction to “sequence” three vacuum pumps ... after all was said and done, it turned out that the best approach was to scrap the original program and use one without the SQOs ... just skimming through the original posts should give you an idea of what you’re up against here ...

if you’re interested in the approach I used in writing the new program, then try to come up with a detailed “program specification” something like the one I gave in the quote box ... the basic idea is to describe the system hardware ... and then tell how the system is supposed to act in normal operation ... and then describe how the system should respond to all of the “what if” scenarios that you can come up with ... once we have that detailed program specification and a complete list of all of the system’s inputs and outputs, then we can really get serious about nailing down a program for you ...

anyway ... I’d suggest that you take a look at the way the vacuum pump program is laid out and see if you think that something along those lines might work out better for you in the long run than the SQO approach ... now I’m NOT saying that the SQO approach won’t work for you ... with enough time and effort I’m sure that it will ... but ... SQOs are best suited for a process that has many steps that occur in a TOTALLY predictable sequence ... (analogy: think about a music box ... it ALWAYS plays the same notes in the same order) ... the fact that your program has to switch between multiple SQOs to control the very same output bits indicates that your sequence does not always follow the same pattern ... so maybe there is a better way of writing this program ...

 

[harryting]

Ron got the right idea. I was going to reply with the same thought.

For a beginner, or even an experienced PLC troubleshooter, the SEQUENCER instruction is hard to figure out. Again, this is fairly simple system with discrete outputs. Using a SQO is more trouble than it's worth, IMO.

Damian, take a look at the two way of doing simple sequence in the logic I sent to you. It might be easier to do it that way. You had the right idea with the "pesudo code" you posted. Try to come up with a SINGLE document in word or excel with sequence step informaton, interlock, input/output, and also a P&ID. After that, we can help you better. Ladder Logic is easy to learn, figure out what to do with the equipment is hard part, PROGRAM the system in plain ole English first.

 

[damianjones]

Good Morning All,

That program was currently in the PLC. I have no interest in keeping it. In fact I would rather have a program that I can easily follow. The program specs are pretty simple:

To start by pressing either startpb1 or startpb2: Turn on the main blower first, if the sensor senses a problem flash both lights, wait 10 minutes then shut down

Turn on System1: start with airlock1, wait 1 minute, turn on blower1. if airlock1 sensor senses a problem flash system1_light wait 5 minutes then shutdown system1 by stopping blower1 wait 1 minute stop airlock1. (main blower stays on)

Turn on System2: start with airlock2, wait 1 minute, turn on blower2. if airlock2 sensor senses a problem flash system2_light wait 5 minutes then shutdown system1 by stopping blower2 wait 1 minute stop airlock2. (main blower stays on)

To shutdown press either stoppb1 or stoppb2: Turn off system1 and system2 on then main blower last

Maybe this is too simple an approach? Is there anything I'm missing?

Thank you all,

Damian

 

[mordred]

No the sequence in and of itself is easy to fifure out. There really isn't too much in the code to deal with. One question though is. Do you want both systems to run independantly of each other?. Either way will work on the logics. Ron is correct concerning the SQO instructions. As you original code showed, there were too many random events that could cause improper sequences. I beleive I've posted most of the problem areas in my previous posts

 

[damianjones]

Hi Mordred,
Yes I would like them to work independently of each other. Actually since there are two start/stop push buttons. I would like either one to start the corresponding system...starting with the outside blower when the user presses the remaining start button the program should some know (if possible) that the outside blower has been started and not try to restart it.

Likewise when shutting down, the first stop button pressed shuts down the corresponding system (but the outside blower stays on) only after the remaining stop button is press does it not only shutdown the corresponding system but also shuts down the outside blower.


Does that make sense?

Thanks for listening to my ravings,

Damian

 

[mordred]

The senser for the main blower which If I'm correct is O:0/2
is this senser a proximity switch checking for rotation of the fan?
If so then if there is a problem that fan you would probably want to deenergize that fan immediately rather than wait 10 minutes. Could you please confirm. I am currently working on rewriting the old program and need a confirmation on the blower that stays on during both sides of the system.

 

[damianjones]

the sensor that will be used is a current senser which will go on the main blower motor. This is a directive from the owner and I don't have much choice about it. There was an auger senser where o:0/2 is currently located. We are ordering the sensor today hopefully.

The wait was requested by the maint supervisor. He wants to check the system before it shuts down. I suspect after the system is is for a while he will let it go to a more automatic shutdown.


I hope I answer your questions. Give me a call or your telephone number and I'll call you if needed.

Damian
715.427.5255

 

[mordred]

Well I've done about all I have time for. I've essentially rewrote the entire code in a basic level format. As I do not have any means to simulate the program. You will have to check it over. I cannot be positive I have all the right states (N/C vs N/O) and I may have missed some needed resets on the timers and latched inputs and outputs. This however will get you started without the SQO instrctions. I will hopefully have more time tomorrow but I will post what I have right now hoping that some of the many experts here can help point out my mistakes.
ROUGH DRAFT ONLY. noticed one step I forgot already I forgot to completely delete ladders 3 and 5

 

[mordred]

her is the program again with ladders 3 and 5 removed

 

[damianjones]

Hi Mordred,

Thanks for the program! I'll take a look and see if I can decifer what is going on.


Thanks all

Damian

 

[mordred]

keep min mind that it is by no means complete. However it should be a lot easier to follow than the original. I may or may not have time to work on it further today.

 

[mordred]

here is a copy of the final working program for you to test. I couldn't test the alarms please remember to remove the two forces on the alarms hopefully this is what your after. You will also need to switch the processor back to micrologix 1200. I had to convert it in order to write this as my company is too cheap to buy rs simulator

 

[damianjones]

Hello Everyone,
It's Damian. First of all I want to thank everyone who tried to help me accomplish this mission. Coming from a programming background you would think I could pick this up and run with it. Alas that is not the case.
So I put the project on the back burner and promptly forgot about it.
Since then I have put in a entirly new network. I went from an old Novel 5 network to a Windows 2003 which included email collaboration system. I put in a new Cisco IP telephone system with spectralink i640 wireless IP phones. Those are the highlight, but I've done bunch of other stuff also.
Sad to say this project remains as it was when I left it. With Mordred's program in the PLC, but not running. Everything it ran I got an error and I gave up.
What I would like to offer is a mere pitance for someone to champion this cause and write the program for me.

You can PM and I'll give you my other contact details and we can negotiate a price. I will answer any questions needed for complete. This money is coming from my own pocket..those who can't do - pay.

Let me know if anyone is interested.

Many Thanks,
Damian

 

[davidg68124]

IF you send me all the items from all the earlier posts in one tidy zip file, I can have it done for you quickly.


Looking for a little christmas cash. Not much, just a little. email me at [email protected] and we can work out the details.

David