PLC Parking Garage Program

It looks good.

Your instructions about the yellow light say "...If the number of parked vehicles in the garage is 23 or 24, the green light is turned off and a yellow light flashes continuously ".

On rung 4 for the Yellow Light, take another look at your comparison "CTA0 < K23". Don't you want the yellow light to be ON when there are 1 to 2 spaces left (CTA0 = 23 or 24)? That would mean that you should look at when CTA0 >= K23 and < K25 ( or CTA0 >= K23 and <= K24).

Parking Garage Program HELP???

Hello everyone,

I have been trying to finish my PLC parking garage program and project for the last several days. I have just two more days until i have to demonstrate my project to the class via webcam. If you have anything to say about my program that you think will help me Please send me a post or message I will be greatly appreciative of any constructive criticism you have. It is down to the wire now so every hour counts. Thank you for all of the help so far and I really mean that. When I switch the PLC on and set it to run the Y0 light lights up but none of the other I/O lights light up. When I push the green NO pushbutton nothing happens. The green light should light up when I press the green pushbutton. Then I should be able to push the blue button and get the PLC to count up. What could I have wired wrong to get this outcome? I will be grateful for any insight to what I have done or forgotten to do in this project.
I am going to try and post some pictures to help you see what I have done. I will also post my latest ladder logic program for your perusal.


Sincerely,

Craig yarges

Looking at your pictures, I think maybe you are calling the "green light" the light on the Pushbutton, not the Y0 output for your Green stack light.

The Pushbutton lights will only go On if you wire them up. If you want the Pushbutton lights to go ON when you press a button, then you need an extra N.O. contact on each pushbutton. Then add additional wiring to those, adding 2 power leads, to the extra contact and to one side of the pushbutton light, to cause the pushbutton light to go ON, and also leave the 2nd contact wired as an "X" Input to the PLC.

If there is only 1 contact on each pushbutton, then you have to use an Output from your PLC (controlled by the Pushbutton Input) to turn on the Pushbutton light ONLY when the pushbutton is pressed. That means you would need about 4 extra Outputs on your PLC and a bunch of extra wires going from the PLC back to the pushbutton enclosure.

If you want the wiring details for your pushbutton lights, you will have to give us the brand and catalog number for each light. That appears to be a standard industrial-type pushbutton unit, so you should be able to find a wiring diagram for the pushbutton and light units from the manufacturers web site.

Reading between the lines, I gather that you did not make any wiring diagrams before you started. Now you are paying the price for that shortcut.

See the attached picture for a schematic diagram of a typical Lighted Pushbutton.

Parking Garage Program

Hello Lancie1,

I have the Pushbutton lights wired so that they are on constantly as soon as I turn on the power. What I was trying to say is that the program should start when I press the green button and the green light on the stack light should light up then. But when I try to run the program the only thing that happens is the Y0 LED indicator light on the Direct Logic D0-05 DR-D Plc lights up. I have the switches contacts wired with one side of them hooked together and wired to the C0 common. Next I wired the other side of each the switch to X0 green switch, X1 red switch, X2 blue switch and X3 clear switch respectively. Then I wired the stack light outputs Y0 green light, Y1 yellow light and Y2 red light and I wired the black wire from the lights to C2. Then I wired the power supply output positive to the PLC + and the power supply negative to the PLC -. Then I have the power supply input wired to a power cord with a 1A fuse on the load input. The power cord ground is wired to the ground input of the power supply and the other wire is wired to the neutral input of the power supply. I hope that this explains my wiring to you and that maybe you or someone can shed a little light on what is wrong.

Sincerely,

Craig Yarges

I don't know the specifics of this PLC (AB tried and true, here), but does it matter if your inputs/outputs are sinking or sourcing? I know that the PLC's we used in school (MicroLogix 1200 C) had sinking inputs and sourcing outputs (or maybe it was the other way around?), which gave me a bit of trouble.

Edit:
After a little further review, could it be that your model of PLC (D0-05-DR-D) has relay contacts? If so, then the PLC will not provide its own power to the lights, you have to do that yourself, the PLC just opens and closes a set of contacts like a relay, hence the whole "relay contacts" deal.
Sorry if there is anything that I am misunderstanding.

Sincerely,
Conor

Parking Garage Project

Hello SandwichMagic,

I think I remember the PLC manual saying something about sinking and sourcing the I/O's. I was also wondering if I needed to have power to the lights but was not sure how to connect the power to them correctly? Do you know how to add power to the output of the PLC? I have never done this before and could use any help you have to offer. I am going to read the PLC manual and see what it says about sinking and sourcing the I/O's. I have never connected a PLC before so this is my first one. How do you connect a power source to the output circuit of the PLC?

Sincerely,

Craig Yarges

So yeah, after looking up your plc, I do believe the specific model you have does have relay outputs. So just like any other relay, all they do is open and close a contact. So it is time to break out a multimeter. You need to see which terminals of your output are connected to which. I imagine that your common connects to the other ones surrounding it, so you should be open from your common to y0, y1, y2, and you should have 0 ohms of resistance from your common to whichever output you are firing. Once you have established that, to hook up the lights, you would pull negative power from your power supply, and connect the common of your stack lights (i believe you said this was black, previously,) to the positive side of your power supply. This will mean that when the output is fired, the contacts close, and you get a complete circuit, and your light works.

So secondary questions.
Do your inputs work? as in do the lights come on when the buttons are pressed? i haven't been able to look at your program in detail, (and if i did, im not sure how much i could get out of AD stuff), but i think that with some of the other more experienced (read: wayyyyy better) members on your side, i think that you will be fine in that department. But yeah, make sure that your buttons work, if not, we will see what we can do about that as well.

By the by, if any senior members see anything wrong with my post, Please correct me if you have the time. It's all about learning, after all.

All the best,
Conor

Parking Garage Program Project

Hello everyone,

I forgot to mention that I am using a "LES-302AW-RYG Patlite Stack Light" to output the signals through. I think I have everything wired correctly except for wiring a power source for the outputs. I am trying to find out exactly how to do that right now so if anyone out there knows how to accomplish this with my Direct Logic DR-05 DR-D PLC then please send me an email? I will be working all night to get this running because I have to demonstrate the project working as described in the instructions for tomorrow evening at 5:00 pm Pacific time zone.

Sincerely,

Craig Yarges

Hello Everyone,

I just saw your reply and will get to work right away. I really appreciate the advice and will be working on this until I get it to work tonight.

So Thank You everyone!!

I will post a reply when I have some new information to post.

Sincerely,

Craig Yarges

SandwichMagic said:

Do your inputs work? as in do the lights come on when the buttons are pressed?

Click to expand...

Oops, that was very vague. What I meant was do the indicator lights come on when you press your buttons?

Hello SandwichMagic,

The only thing that happens when I power it up is the Y0 output light on the PLC comes on.

Okay, that is a start, that means your program is working as intended, just waiting for input and trying to drive output. So if you press the buttons does anything happen?

Parking Garage Program Project

Hello Everyone,

I have wired the Patlite stack light like you said and am about to try and see if it works. I will post after I get the PLC connected and downloaded and then see what happens?

Sincerely,

Craig Yarges

Parking Garage Program

Hello Everyone,

I am happy to report that at least I have a green light on my stack light lit up. I now have to try and get the program working because when I tried it it did not switch to the yellow and then the red when I pushed the push button for 23, 24 and twenty five cars entering the garage. But the green light lit up before I pushed the green button to start the program. So I am not sure what to do next? I have attached a copy of my program to this post for any help I can get. Thank you.

Sincerely,

Craig Yarges