LogixPro Door Simu

[Rengas]

Hello everyone,

I have attached my printout of my Logixpro door simulation.
Its all working fine but the only thing im having problems with is when the door is going up and i press the close button it closses when it shouldnt. Nothing should happen.

I appreciate your ideas on how to correct this. Thanks

 

[Lancie1]

Rengas,

Did you read the instructions for LogixPro Door Opener Exercise 4? (Probably not. I have not met a student here yet who actually read and studied the instructions for their project). The Exercise 4 instructions advised the use of "flag bits".

The utilization of Binary or Integer Table bits to Flag specific conditions within your program would be appropriate.

Heck, Mr. Bill Simpson even told you WHICH bit to use for the flag! (However, if you use TWO flag bits, you can do the Motor Up with one rung, and the Motor Down with one rung.) Set up your very FIRST rung to look like the attached picture. Also your motor output rungs are much too simple. You need to use the Motor Up and Motor Down Limit Switches to prevent door overtravel. Avoid using Latch and Unlatch for the motor outputs. That only leads to trouble and extra logic to unlatch the bits. What if you don't get a motor unlatched? It could suddenly take off running the next time that power is restored.

In case you can't get a copy, here is an excerpt (for educational purposes as allowed by copyright law) from the ProSim Student Instructions:

Student Programming Exercise #4:

In this exercise we want you to add one final touch which will possibly extend the life of the door hardware. Starting and stopping the door motion obviously puts a strain on the door hardware, but reversing the direction of the door without giving it a chance to fully stop causes an even greater strain. We want you to modify your program to prevent the possibility of immediate reversal. As we don't need much of a delay, the following additional criteria should suffice:

• If the door is currently opening, pressing the Close Switch will immediately halt movement. Door movement will remain halted when the switch is released.
• If the door is currently closing, pressing the Open Switch will immediately halt movement. Door movement will remain halted when the switch is released.
• Once movement is halted, and all push buttons have been released, then door motion in either direction can once again be initiated by pressing the appropriate Open or Close button.
• The utilization of Binary or Integer Table bits to Flag specific conditions within your program would be appropriate. Also, the retentive OTL and OTU instructions may be utilized freely at your discretion.

Hint: If you review the foregoing criteria carefully, you should note the the motor should only be permitted to start after a specific set of conditions have been met. The conditions being that the motor is stopped, and all switches are released.. Since this same set of conditions will apply to both the door opening, and door closing operations, this may be the ideal time to use flagging.... By flagging, I mean that you will use a bit in the PLC memory (such as B3:0/0) to indicate that a specific condition, or set of conditions exist.

Example: You might add a new rung to the beginning of your program, and insert instructions to test that the motor is stopped, and all switches are released... Latch bit B3:0/0 True (ON) if so, and name it something like "Ready-To-Start".... Now you can add an XIC instruction addressed to this "Ready-To-Start" bit to both your existing Motor UP, and Motor Down control rungs, and this will confirm that the motor may be started.. Of course you will need to unlatch the "Ready-To-Start bit once the motor is started.

BTW: Almost any unused bit may be used as a flag, but since RSLogix has set aside the B3: memory area, and this memory area displays in binary format by default, it's commonly used for this purpose.. N7:1/12 would work however, but the N7 area is normally used as place for storing integers as this memory area is displayed in decimal by default... Additionally, it is sometimes possible to use an Operator Panel lamp as flag if the conditions suit.

 

[Rengas]

Thanks for taking the time out to read and reply my post. I'll try it out.
Thanks again.

 

[Lancie1]

Let me know if you have questions. Notice that I have Unlatched the Flag Bits on Rung 000. That means on the rung for each motor output (Motor Up and Motor Down), you will need to Latch one of those bits. Using this method, you should be able to perform all of the specified functions with about 7 logic rungs total (counting the important END statement).

 

[Rengas]

I appreciate your help. I haven't been able to do re program the door
because iv been very busy at work. My shift can span between 12 to 14
hours and im shattered when I get home and I have to repeat that 5 days a week.
I will let you know as soon as iv done it.

Thanks again.

 

[Lancie1]

Rengas,

I know what you mean about your work schedule. I once worked 12-hour days 7 days a week for 3 years. I was able to retire early but I still don't know if it was worth the physical wear and tear.

 

[Rengas]

I appreciate you checking on my progress.
Just got home and its 2300 hrs. It looks like I cant
do a thing tonight.

Im hoping everythinh works out because im doing this electrical/electronic
course so I can get out of this long hours trucking job.
I know nothing about electronics or plcs but hope
to get through the course.

Thanks for chexking again.

 

[Lancie1]

I know nothing about electronics or plcs but hope to get through the course.

What is your real goal: (1) to learn enough about Electronics and PLCs to be able to work in that field (a nice long-term goal that could get you a job); OR

(2) Do you just want to just get through the course (a short-sighted goal that will get you a grade but maybe not a better job)?

Usually the results depend on the amount of effort expended. When I was a college student (2 different times for 2 different fields), I had to give up a lot of other activities in order to buckle down and study. I have never been able to get something for nothing. Studying efficiently is a skill, and I think most youngsters never learn how to do it. Distractions are a problem. To study and learn, you must find the right place that can be closed off from noise, music, phones, text messages, television, and with a sign on the closed door that says "Bother me and you die!" I know a bunch of you will say "Hey wait a minute, music (or TV, or whatever your poision happens to be) helps me to concentrate." Sorry, you are fooling yourself. Many studies and tests have been done that shows otherwise: the more distractions, the less you will learn.

 

[Rengas]

I have no social life I have no distractions, no time for tv. I know I have to
give up something to gain something but after working 5 day week
and in excess of 60 hrs and having 1 day in college I only have a day left
which I cram all my assignments and my run around for the week into.
Its not been enough. Im even checking this forum from my fon when im working.
I wud like to get good grades in all my subjects including plcs then apply for a job then gain
experience that way. At the moment every little time I have I try to study. I intend doing an electrician
course when I finish this one as most of my classmates are qualified electricians which helps.

 

[Rengas]

Im trying to learn everything and as much as I can. No matter
how hard the conditions are. Its my only way out which is why
im here.

 

[Lancie1]

Its my only way out which is why I,m here.

I understand. Now what can I help you with? PLCS? Electrical controls? Wiring? Financial? How to save money? How to live on a budget?

If school and training are your only way out, then you need to bump it up to "Prime Importance" and bump the work down a notch. Maybe your employer would allow you to be a part-time worker and only work 30 to 40 hours a week. That would give you some time each night to hit the books. If you are going to do both work and school, you have to decide which is the most important, and let the other slide.

How many hours would you have to work to proivde enough money to "live on" and go to school? That is how many hours you need to work right now, no more than that. By "live on", I mean the basic necessities such as shelter, food, educational fees, and transportation to work and to school. All other activities, such as entertainment, new clothes, and eating out, need to be stopped until you finish your training. Get rid of your cell phone and the associated fees. You can get by without it, and will have more time.

 

[Rengas]

I dont do any of those. Im vegan. Im already down to the bones in
financial terms. My plan is to do more studies during vacation from college.
I find Plcs very interesting and is one of the areas I may specialize in. I didn't even know
what plcs were until I started the electrical/ electronic course. I understand its equivalent
to university year 1. For the time being ill take things at a slower pace. I will find and cut my working
hours .

 

[Rengas]

Hahaa! everyone would want to be assisted with money. You wonna send me some? That would be very nice. .
Im working on how to cut my working hours. Im earning less now than 4 years ago due to the recession which is part of the problem. I would struggle to earn less than i currently do and i doubt if my bosses wud let me do any less hours than im currently doing. I'm now paying for the expenditures i made during the boom economic years. For now i have to try harder as the course is only for 2 years.

 

[Lancie1]

One good way to think about the LogixPro Door Simualtor Exercise 4 is "how to you use one pushbutton to do 2 or more functions"?

Answer: You have to look at the situation by time slices or events. If the door is STOPPED, how can I get it to CLOSE? But if the door is going UP and I hit CLOSE, how can I make it STOP? In other words, how can I use the CLOSE button to do two functions (at different times)?

In the same way, how can I use the OPEN button to do two functions at different times?

There are many methods, and I know of 3 very different ways to write this program, using 2 flags, using 2 flags and 2 alternators, and using state tables and a "state" program where you define all possible states.

 

[Lancie1]

I can't tell you how to get more money, but I can help you find ways to make what you have go farther. Bartering (swapping work or objects for the things you need) is one way, but it requires some time that you don't have. Another way is to avoid services that you can do without (phones, cell phones computer access, satelite TV, movie channels, any kind of entertainment. I go to the library once a month and check out both books and movies. I often buy used books at the library for 50 or 75 cents (that have been removed from the library shelves due to age). Yes they are old, but so am I. Some of these books seem modern to me even though the library thinks they are too old to be of interest! If I have not read it, then for 50 cents I can be entertained for several nights.

I am reading one old book now about the alien spaceship crash at Roswell, New Mexico in 1947 - very interesting eyewitness accounts which were later covered up by the US Army and FBI. I can't figure out why they thought it necessary to try to hide this incident. Maybe it was so they could learn the alien technology without sharing it with another country. One of the eye witnesses at the crash scene described finding "wires" they he took home and found that light would travel through them. That was mostly unknown technology in 1947. Many years later, about 1970, out popped fiber-optic cable from the military-industrial complex. How much of our technology is really home-grown, and how much has been imported from other beings?