NewBee needs help!!!!

I'm new to PLC programming and need some help. I'm a member of the Reading Company Technical & Historical Society and we're dedicated to preserving the Reading Railroad. we have an HO modular layout that we exhibit at public venues. we're reproducing Hershey Park, in Hershey PA, in HO scale. my job has been to build an operating HO version of the kissing tower ride. I have managed to do that. to control the whole park we are going to use an AB SLC 500 fixed 1747-L30a PLC, 1746-IB16, and 1746-OW16. I have the unit, software, cables, etc. and it works. I have managed to program 9 ride routines. start a timer (load ride), start ride, start a timer (ride duration), stop ride, start again.

I'm having problems programming the kissing tower. I have a lower limit sw. I:1/1, an upper limit sw. I:1/3, a hoist motor (to raise the cabin) O:0/0, and a reversing relay O:0/1 (to change motor polarity). this is what needs to happen:
bottom limit sw closed I:1/1, then start load timer T4:0.
load timer done T4:0/dn, then latch and turn on hoist motor O:0/0.
top limit sw closed I:1/3, turn off output and start ride timer T4:1.
ride timer done T4:1/dn , turn on and latch reverse relay O:0/1 and hoist motor O:0/0
start again.

this is what I programmed:
0000 I:1/1 T4:0

0001 T4:0/dn _________ O:0/0
O:0/0 * not I:1/3

0002 I:1/3 T4:1

0003 T4:1/dn ___________O:0/0
O:0/0 * not I:1/1 _______O:0/1

lines 0000, 0002, and 0003 work great! in 0001 O:0/0 won't turn on???? the only way I can get it to work is by changing O:0/0 in line 0001 to a different output say O:0/2. if I do that then I have to run a jumper wire between the 2 outputs. seem weird that this won't work.

anyone have an idea???
frustrated,
thanks in advance,
Bob..............

Is O:0/0 being used elsewhere in the program (turned off, when your logic is trying to turn it on?). If you post your PLC code, others may be able to diagnose faults a little easier

kiwi sparky is correct. You cannot make the same output true at more than one place in the program, unless using OTL instruction. I have never found this to be a good practice, but have seen it done successfully.

The best alternative is to make different memory bit (B3:0/0, B3:0/1) then OR these bits in another rung to make the desired output.

HI,
Thanks for your reply!

O:0/0 is only used on lines 0001 and 0003. I would like to post the code but I don't know how to do that. I'm using RSLogix 500 V6.00. I tried to copy the code and paste it here but it put a lot of weird stuff with it. if you could please tell me how to post it, I will do so.

SOR XIC I:1.0/1 TON T4:0 0.01 1800 0 EOR SOR BST XIC T4:0/DN NXB XIC O:0.0/0 XIO I:1.0/3 BND OTE O:0.0/0 EOR SOR XIC I:1.0/3 TON T4:1 0.01 3200 3200 EOR SOR BST XIC T4:1/DN NXB XIC O:0.0/0 XIO I:1.0/1 BND BST OTE O:0.0/0 NXB OTE O:0.0/1 BND EOR

in the mean time I will play around with the OTL instruction. I'd like to try the B3 but I don't understand how to use that yet. I haven't gone that far in the training course I have. I've just used basic input and output instructions.

thanks again for your help with this. you never learn unless you ask questions.
thanks,
Bob...............

That is the problem you cant use the same output twice in a program.

two methods easiest is to zip the RSS file them click go advanced on your post the other is to use a PDF99s.exe to convert the RSS file to pdf them, follow the same procedure as above

Instead of using O:0/0 at 0001 and 0003 use B3/0 and B3/1 respectively. Make a new rung
SOR BST XIC B3/0 NXB XIC B3/1 BND OTE O:0/0

Hi Chuck,
I'm sorry to say this but I don't know how to do the B3 bits. I've never done anything with them. could you explain it to me? I've also attached the code I have now if you wish to look at it.

bobc1957 said:

Hi Chuck,
I'm sorry to say this but I don't know how to do the B3 bits. I've never done anything with them. could you explain it to me? I've also attached the code I have now if you wish to look at it.

Click to expand...

Example of altering your double output coil to using B3 bits

I have only just got in from a breakdown and its 2.30 am here so i have only looked at your first 3 rungs of code with the double output coil.

I have altered these and added rung 4

Hope it helps

Its untested....

Hi Bob,

You should post a few pictures so we get a better idea of what you are doing...

Try Dave's programing ideas and let us know what is or is not working

Mark

Bob,

I find your project VERY interesting. I have always wanted to get into model railroading. I see some ways to minimize the number of rungs, and also make the loading of the two Ferris Wheels more realistic. I think a Ferris Wheel is loaded by waiting for unload, then load, moving to the next car, then repeating. When all cars are filled with new riders, the wheel then rotates for some time period. The Double Ferris Wheel could be further refined by adding a load time for each wheel.

Here is one way to add the Ferris Wheel realistic loading, and reduce the number of timers from 20 to 12, and reduce the number of rungs from 41 to 24. You still have the abilty to easily change the Load and Run time for each ride.

Hi Everyone,

first I'd like to thank you for your help. this is a neat site! I've also been very busy this weekend so I haven't had a chance to try the programs. we have the Berks Jazz Fest going on and I play bass in a church group. we'll be performing tonight so my whole day will be spent there. I'll try the programs tomorrow and let you know how I make out. I also have the kissing tower in pieces because I finished painting it a week ago. I'll try to get it together over the next 2 days and I'll upload a few pics for you to see. the rest of the module is still under construction. we wanted to make sure we could control it before going ahead with the project. we probably won't have it done till the end of the year. if you wish you can check my personal web site for updates. over the next few weeks I'll be posting pictures of the tower construction and you can see my home layout.

www.nomanerr.com

I hope that's legal to post here? once this weekend is over I'll let you know how I made out.
once again I really appreciate your help!!!!!
see ya,
Bob...........

okay, so I couldn't wait to try these! here's what happened.

Daves code for the tower works exactly the way I wanted it.

Lancie1 your version starts out right but when I simulate the tower reaching the top limit switch it keeps the hoist on till the timer cycles. BUT!!!!! your code for the other rides works great!!!!! all I'll have to do is set the timer to match the movement of the ferris wheel. this is going to blow peoples minds when they see it! I don't think it could get any more realistic.

now I have to take some time to learn how this all works.
thank you soooooo much for your help. I will keep you informed of the progress. I'm also planning to do some stuff with my home layout too. that will also show up on my web site.

thanks again. if you're ever in Reading PA let me know and I'll treat you to dinner.

Bob............

here's a picture of the comet rollercoaster we have. it's 2' x 1'. the modules we'll be building will be 8' x 3' and there will be 4 of them.

Bob,

I am sorry the Kissing Tower did not work correctly. I have looked at it again and I did not spot anything right away. Can anyone else see why my version did not work?

I will put it on the LogixPro Simulator program and see what happens.

EDIT: I think it is the difficulty with manually switching the limit switches at the right times. Try this Version 3. I tested this one, and managed also to reduce the Kissing Tower to only 3 rungs!

Hi lancie1

I tried the new code and, I don't know what you changed, but it worked.

I talked to guys in the club and they are all excited about the Ferris wheel. amazing what will turn on old farts! lol...... ANYWAYS, I was wondering if you could explain how it works and what I can adjust to match it to our model. I don't understand how you did the counting for the loading to know when to start the ride. I'm not sure how many seats are on this thing so I'll have to adjust for it. not that we need it perfect but hey, if you got it, flaunt it!

I asked about the double ferris wheel and this same routine won't work. the central support turns and there are belts hooked up that make the wheels turn. so the whole thing moves as a unit.

I'm sitting here watching the lights turn on and off. my wife thinks I'm nuts. OH WELL!

thanks again for all your help,
Bob............