# Dear all plc experts



## McClary’s Electrical (Feb 21, 2009)

smb43432 said:


> I could really use your assistance.
> 
> Please explain how you would right this program for a parking garage.
> I will be using a micrologix 1000 controller and Rslogix 500 to write.
> ...


 
I'm certainly no expert, and it's been years since I wrote a program with RS logix to a plc5 or slk 500 or micrologox 100, but as far as I can remember, the micrologix 1000 does not have a way to keep track of the days of the week. It would be simple enough to make the counters work, and there are enough unputs to do what you want, but the days of the week have me stumped at the moment.


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## smb43432 (May 25, 2010)

I am stumped by the entire thing.. any input (pun intended) is appreciated.


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## McClary’s Electrical (Feb 21, 2009)

smb43432 said:


> I am stumped by the entire thing.. any input (pun intended) is appreciated.


 
I took a lenghtly course in programming before I would even attemp it. If you haven't been specificcally trained in RS linx and RS logix, the chance os you "figuring out" how to write the program would be about 1 in 1,000,000,000. 

What's the timeline on the project? I can get it done for you.


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## smb43432 (May 25, 2010)

I have a week. I am taking a class but we cover so much I get confused.


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## John (Jan 22, 2007)

Your first obstacle will be to having to use Allen Bradley. :whistling2:

Here is one half of the solution with some fine tuning required.




View attachment 4519


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## smb43432 (May 25, 2010)

Yes i forgot to add I can only use AB's


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## John (Jan 22, 2007)

smb43432 said:


> Yes i forgot to add I can only use AB's


AB is expensive.

Most PLC programing is the same and my example can be converted to AB easily.


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## smb43432 (May 25, 2010)

Anything that would give me an idea will help!


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## smb43432 (May 25, 2010)

What is a cc? And only 2 pb's on my controller.


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## IMM_Doctor (Mar 24, 2009)

*You cant get there from here*



smb43432 said:


> I could really use your assistance.
> 
> Please explain how you would right this program for a parking garage.
> I will be using a micrologix 1000 controller and Rslogix 500 to write.
> ...


Your PLC class is OUT OF DATE. Micrologix 1000 is a 20 year old obsolete product.

Even PLCs are doing 32-bit and 64-bit processing.

A ML1000 can only support about 100 input (sensors). A Parking garage can hold a hundreds of vehicles.

Counting cars in and counting cars out is achievable, but will CERTAINLY be corrupt in short order without any means of recovery.

A control system is only intelligent as it's eyes (sensors).

Suggestion: Fly into Baltimore, and check out the parking garage. It is the most impressive use of sensor automation for general public use that I have ever seen.

There is an ultrasonic sensor above 1000 parking spaces in a multiple level parking structure. As you approach the structure, there are LARGE visual displays that indicate EXACTLY how many empty parking spaces are available. If there are 200, you then drive up the ramp, and as you pass level 1, you can see how many may be available one each level. If there are none you procede to the next available level.

Now here is the cool part, when you elect to pull into a level with 123 emmpty spaces, you can drive very fast and look above for a green light.

Above each space there is a RED/GRREN light based on the results of the ultrasonic dector above each space.

As a Controls Engineer, this was one of the most euphoric home runs that I ever experienced. 

I flew in in out of Baltimore a few more times, and I am jealous. My airport is shyt for parking.


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## John (Jan 22, 2007)

smb43432 said:


> What is a cc? And only 2 pb's on my controller.


CC means Counter Comparison as in when the up down counter 001 = 300 it will turn on.

If you want to continue with this project, you got a lot to learn in a short amount of time. 

Something to guide you.
You need to take a course in electronics to learn the basic and, nand , nor, not, etc commands of electronics which apply to PLC programing. 

You need to work with relay logic, enough to be able to wire up a start/ stop, forward/reverse, jog circuit in you sleep. If you don't know how to do or understand relay logic doing PLC programing will be really, really, really hard. 

test: explain this control

View attachment 4524


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## smb43432 (May 25, 2010)

I understand and,not, or, and all that pretty good.

The way I read your problem.

Line 1 - if pb 1 is pressed or cr1 is on, then the timer comes on and output 1 is turned on.

line 2 - if pb2 is press and the timer is on, or if cr2 is on, then the output would come on.

line 3 - same as line 2?

line 4 - same as line 3?

line 5 - same as line 4 except the light is also an output.

How am i doing?


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## smb43432 (May 25, 2010)

*bumpity*

bump .........................................................


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## smb43432 (May 25, 2010)

John said:


> Your first obstacle will be to having to use Allen Bradley. :whistling2:
> 
> Here is one half of the solution with some fine tuning required.
> 
> ...



Does this look correct? I only have 2 days to work on this. I'm confused why are all your counters connected?


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## controls (Feb 13, 2009)

Not sure where to start... Above example is not A/B logic. That counter example has a count up , count down (CUD C001) and reset all in one. A/B you will have CTU, count up and CTD, count down counters. So, if you use a sensor or a switch to trigger a count that is what you are going to start doing. Switch or sensor is made you count up in the rung (cars entering). Cars existing, you count down CTD.For example for your total count you set your preset to 500 and accumulate the counter or count down your counter. You can set more counters for public and reserved counts. Control those with a selector switch to activate them,plus sensors... Example weekend mode is active, cars coming in count up or down. If the counter done bit is not high you should have an output for green light/indicator telling you you still have more space. If a counter done bit is high, you are full and turn on a red light?We could go on more to talk about using CMP, compare options to compare your different counters, ADD, MOV, LIM. There are many ways of doing this. Just click on the instruction palette on A/B sofware programing window, that should help you. There is a way to set clocks and setting days in the logic too.


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## controls (Feb 13, 2009)

By the way,micrologix1000 is limited, does not have CMP option or LIM that I mentioned. You may use GEQ,GRT,LES,LEQ..............Not sure about capturing the days with it either.


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## Hunter1151 (Nov 4, 2010)

Seems you want to use the rtc in the plc, but that controller does not have one, second how do you determine where the cars are going, and third I would use counters and a FIFO command because when a car leaves you want the counter to count down allowing another car to enter


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## jude (Nov 23, 2010)

this is a common PLC lab for basic allen bradley programming


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## McClary’s Electrical (Feb 21, 2009)

jude said:


> this is a common PLC lab for basic allen bradley programming


 

ok,,,post the lab work you did then:whistling2:


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## jude (Nov 23, 2010)

*car park*

Big mea culpa I did not read the full question earlier today, I have done programming courses years ago and the car park was part off the labs, we used plc 5 and the program did not include differant weekend numbers although I think you can use the s status bits as timers for day /date any way our lab from what i remember used 2 up down counters and then subtracted the acc from 200 and 500 and used n integers as destinations which using a frd and a tod can be displayed on a screen


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## tommu56 (Nov 19, 2010)

Are you stuck with the 1000?
The 1100 has a realtime clock in it 1000 does not.

Is it just push buttons or switch manually for weekends or automatic?
What type of output so you need like a lights to say full for each choice so an attendant can see it?
What type of input push button by attendant or some for of automaton?


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## Grounded-B (Jan 5, 2011)

smb43432 said:


> Does this look correct? I only have 2 days to work on this. I'm confused why are all your counters connected?


 
I'm sorry, but, how are you going to learn anything - if you are asking for the total solution? I suggest you re-take the beginning PLC course until you are very comforable with PLC logic. Then you will start to think on your own and at least have some ideas to try.


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