new member,logixpro student

[ijr900]

Hello all ,this is my second posting but the first one was lost in the eithernet.I am working my way through the prologix plc simulator and will be posting some of my completed projects soon.my name is Ian Robinson,i am an electrician living in the uk.hope to hear from you.ijr900here is the door sim that i did

 

[randylud]

Code looks good, does it work? I use this one for my students all the time and it drives them crazy. Welcome to the forum!

 

[ijr900]

hello randylud, yes the programme works ok.I was a bit worried about posting it,but then if someone wants to lift it they would only be cheating themselves.You say that you have used this sim for your students,do they use a different ladder to get the same result,is there a correct way

 

[randylud]

There are many ways to program this door sim, and all those that work are acceptable. The best way is always the cleanest, simplest way in my estimation. I do use LogixPro in my PLC course that I teach and find it quite useful in getting students ready for the real thing. Have you worked on the exercise #4 of this sim? It involves using a "flag" approach to operating the door. Good luck, and keep coming here for advice or just interesting reading.

 

[ijr900]

logixpro student

hello ranylud,been away for a while,did not try ex4 of the door sim will come back to that one.have done the silo sim ,left me a bit burnt out but am now picking up where i left off.hope to keep the momentum going this time,will be coming back to the site for advice soon no doubt.thanks Ian

Robinson

 

[randylud]

You should avoid using output instructions in series as you have in your rung 001. LogixPro will allow you to do that but most PLC programming software, especially AB before the ControlLogix platform. So, keep up the good work and remember, the program just tells the PLC how you want things to happen. Keep the program simple, straight to the point and you will come out ok. If you want a program to compare your work to, let me know and I will post the door sim with all the bells and whistles.

 

[Webhead]

I do use LogixPro in my PLC course that I teach and find it quite useful in getting students ready for the real thing. Have you worked on the exercise #4 of this sim?

Is this LogixPro something on this website??? My wife is a software/web developer and curious about PLC programming. I've been doing PLC for quite a few years and don't feel like dragging a PLC home for her to play with. But if she can play with it on the web with some tasks to complete she can see how it works.....

 

[randylud]

No, LogixPro is not available on this site but is available here: http://thelearningpit.com/ and I would highly recommend you getting a copy to see how powerful it really is. If you need more info or help, just holler.

 

[craig_avanzar]

randylud,
I have been working with the LogixPro and you mentioned using flags to operate this simulator. I'm self taught so when I didn't know about the flags I went on with the idea of coming back to it later. If at your convienence you could give me some pointers they would be greatly appreciated. I have this done w/o flags and can post all of my work.
Thank you,

Edit: I didn't mean to step on this thread but thought it might be helpful to the OP as well.

 

[Lancie1]

Hello, Ian

Welcome and congratulations on the successful Door Simulator. Do you want comments and criticism on your programs? I assume that you would not have posted it if you didn't want other opinions. Note I said "opinions". That is all they are.

Your Rung 0 Branch 2 O:2/4 Unlatch and Rung 1 O:2/1 Solenoid have Outputs embedded where normally you only want to use Inputs or contacts from Outputs.

Your Rung 0 looks pretty complicated even for Exercise 3, using the Selector Switch. I think you are putting to much emphasis on the motor.

Beginners may overlook the fact that the PLC is controlling the WHOLE machine, not just the motors. Thus it is often assumed that if a motor is not spinning then the machine is not in RUN mode.

Do you remember this instruction from the LogixPro Exercise 1?

The RUN light will remain energized as long as the system is operating automatically.

I do not believe that your program keeps the RUN light on as instructed, but only when the motor is on or the solenoid is on.

On most machines, the machine can be and often is in RUN mode, even if there are no motors running. It may be simply waiting for something to happen. Does that mean it is inactive? Put another way, because a bus is sitting at rest in the street, would you assume that it would not run over you if you walked in front of it? Not by a long shot. The system is still "running", even though it may not be moving at the moment.

TIP: Think about making Rung 3, Output O:2/2 a "System Run" light. Then think about how it would simplify some things if you moved the Start and Stop functions from Rung 0 to Rung 3. Suddenly when you hit Start, the system goes into RUN mode, output O:2/2 goes on, when you hit Stop, output O:2/2 goes off. Now all you need in Rung 0 (to tell the motor if the machine is in Run Mode or not) is a contact from O:2/2. This one action should simply Rung 0 a bunch.

Another way to simplify Rung 0 is to use only 3 parallel branches, one each for Selector Positions A, B, and C. That is all you should really need, with the O:2/2 contact for "System Run" controlling the Selector Switch branches.

 

[randylud]

randylud,
I have been working with the LogixPro and you mentioned using flags to operate this simulator. I'm self taught so when I didn't know about the flags I went on with the idea of coming back to it later. If at your convenience you could give me some pointers they would be greatly appreciated. I have this done w/o flags and can post all of my work.
Thank you,

Edit: I didn't mean to step on this thread but thought it might be helpful to the OP as well.

Craig,
Welcome in the thread and all input is valid and appreciated. When I mentioned flags earlier to IAN, I was speaking about the 4th exercise that asks for the door to stop moving either up or down when the opposite direction button is pressed. Normally, if you follow the outline that Bill Simpson lays out for the exercises, you will get through #3 and find that if you push the up button when the door is going down, it will stop and immediately go up. So, exercise #4 is about getting this not to happen. Using a "flag" is just a term that some programmers use to indicate the bit that tells one rung that something else has occurred in another rung. So, this is not the only way to do the operation for the 4th exercise but it is clean and simple. That is always desirable from a programming standpoint. I have a copy of this complete program that I would be happy to send you if you like. Just to compare to your own.

 

[craig_avanzar]

randylud,
Thankyou for the offer and yes I'll take you up on it. If you could just PM me with it and I'll start work on it right away. My job allows me time to do this.

 

[AlexKall]

Finished a Step 7 project so I thought I would take a few minutes to lern something about AB (Logix is AB right? ) so I got the demo and made Door Ex #3. Really hard when you're used to another program like Step 7 and GX IEC. Pretty interesting! I have used a simular training program for Mitsu plc.

My program is in the BMP (sorry couldn't get it to jpg) file below

EDIT: More then 8 years ago, was involving F1 if I remember it right

 

[Lancie1]

Hello, Alex,

Welcome to PLCS.net. Your program looks like it will work. Here are a few comments.

Rung 000: The Stop and Motor Down contacts need to be in series with the LS1 contact. Suppose the Open pushbutton sticks in the closed position? You could not stop the door even by holding down the stop button. If you move the Stop button so that it breaks the entire rung, then your program will be safer. This comment applies to the Close button in Rung 002 also. I like to put the Stop button immediately to the right of the left power rail, to remind me not to put anything in parallel with the STOP function. STOP should always perform the stop function, no matter what else happens.

Rung 004: Consider using LS1 and LS2 to control the Ajar Lamp, instead of contacts from the Open and Shut Lamps. Always use the most direct possible indicator, the switch closest to the action. What if somebody later changed your program and inserted some conditions on the Open or Shut Lamp rungs? Suddenly your Ajar lamp would not work correctly. It would not matter much here, but the principle should be followed consistently. In many cases it will cause some problems.

 

[AlexKall]

Welcome to PLCS.net. Your program looks like it will work. Here are a few comments.

Thank you very much! I've been no more then a friendly stalker on here but thought I would get out of my dark spot and say a few words before I get back in to the dark spot again that I like so much. That dark spot has alot of good reading!

Rung 000: The Stop and Motor Down contacts need to be in series with the LS1 contact. Suppose the Open pushbutton sticks in the closed position? You could not stop the door even by holding down the stop button. If you move the Stop button so that it breaks the entire rung, then your program will be safer. This comment applies to the Close button in Rung 002 also. I like to put the Stop button immediately to the right of the left power rail, to remind me not to put anything in parallel with the STOP function. STOP should always perform the stop function, no matter what else happens.

Point taken, I did not notice that failure of saftey when I breifed through my program and that is a big misstake, especially in the closing of the gate as if the button do get suck and there is no way to stop it (of course there should be a ESTOP ) and someone could be crushed/injured and as the wisdom of life say: If it can be done it will be done, sooner or later

Rung 004: Consider using LS1 and LS2 to control the Ajar Lamp, instead of contacts from the Open and Shut Lamps. Always use the most direct possible indicator, the switch closest to the action. What if somebody later changed your program and inserted some conditions on the Open or Shut Lamp rungs? Suddenly your Ajar lamp would not work correctly. It would not matter much here, but the principle should be followed consistently. In many cases it will cause some problems.

That I was aware of, just a quick thing (I know that it would be just as quick using the Inputs but as I had the O: address in my head and it was time for lunch

Will defenetly remember the first comment as that is a real serious flaw and I can picture myself seing someonegetting injured it is something that sticks in memory. Don't do "håll kretsar" (sorry don't know the propper name in enligh) this way unless I'm stuck with an extreemly simple plc as this way is somewhat flawed (my opinion) as it is rather simple to get stuck in two "Executions" at the same time if you make a simple misstake. And when presured of deadlines it's easy to oversee things

EDIT: Can't thank you enough taking time and going through it. Also is there any better way of using inernal addressing then N7:x/x?

EDIT2: Rewrote it and hopefullt it can make sense now. Brain is to tired now to make much sense and I'm sorry about that. Still 1 hour and 10 minutes till the day is at it's end, unless something unexpected rolls in through the office