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  #21  
Old 06-02-2007, 11:46 AM
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Still clueless, but I'm getting better.

Bolt--from the viewer's perspective in your picture, which way does that gate move? Closer/farther to the viewer, with the ends riding on the wall?
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  #22  
Old 06-02-2007, 12:10 PM
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It occurs to me now that this is simple for me because I do it every day; if anyone looks through the code and has questions feel free to ask and I'll try to answer them
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  #23  
Old 06-02-2007, 12:24 PM
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Wow, mark, you really have really put some effort into this, I really appreciate it. What does this setup need as far as a gate location signal?

Dubby, yes, the gate comes towards the picture taker, on the tracks on the wall. It is currently at about the 70 foot mark, with 120 being behind it.

Thanks for all the input, guys, this has gone alot faster and with more responses than I expected it too. Always a good site.
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  #24  
Old 06-02-2007, 12:38 PM
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In this program I assumed that location would be given via multiple switches (one at 60, 50, 40, etc). Now the switches could be photo eye, or prox, or even wobble; the PLC doesn't care or know, its just looking for its inputs to turn on and off.

It could be re-done for a linear pot easily enough as well if you decide to go that route.
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  #25  
Old 06-02-2007, 12:53 PM
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I pretty much follow your ladder, I've been around/installed/tweaked PLC's, but I aint no programer. I have a guy in California that built the PLC's for some of our other automation, and he sends out new chips for any major re-engineering of the cycles. But this guy is crazy busy and hard to get a hold of, so I wasn't really looking to go to him on this one. Little did I know that there was a resident PLC guy right here! We may need to get together on this sometime and hammer it out completely, and then figure out a form of compensation for you.

Well I am going to have a closer look, and see if proximity switches are going to be effective or not. They would have to come from above, as to avoid them being in reach of cows.

I assume a hand/off/auto switch could be easily implemented in this design.

I think I am going to have to rewire a considerable portion of this, the fan starters are currently +/- 200 feet away, thermostats run them that are 100 feet away, and I don't feel like running 1000 feet of wire to make it work! But this is all starting to come together in my head, and it should work great.
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  #26  
Old 06-02-2007, 01:05 PM
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Quote:
Originally Posted by Bolt View Post
I pretty much follow your ladder, I've been around/installed/tweaked PLC's, but I aint no programer. I have a guy in California that built the PLC's for some of our other automation, and he sends out new chips for any major re-engineering of the cycles. But this guy is crazy busy and hard to get a hold of, so I wasn't really looking to go to him on this one. Little did I know that there was a resident PLC guy right here! We may need to get together on this sometime and hammer it out completely, and then figure out a form of compensation for you.
No worries, glad to help and I'm sure we can get together at some point if needed, but I'm also pretty sure this is something you'll be able to get done pretty easily - excellent first ground up PLC project really... you may find you don't use the guy in CA as much after you get this done; you'll probably just start doing the PLC work yourself once you see how easy it is :evil:

Quote:
Originally Posted by Bolt View Post
Well I am going to have a closer look, and see if proximity switches are going to be effective or not. They would have to come from above, as to avoid them being in reach of cows.
Another possibility would be a laser range finder... probably cost prohibitive, but might be worth looking into.

Quote:
Originally Posted by Bolt View Post
I assume a hand/off/auto switch could be easily implemented in this design.
Shouldn't be too difficult, but it'll probably put us over the 100 byte limit for the free version of the programming software. Currently its got an on/off switch, but no hand. If you do want to do hand/off/auto then in hand will you want to be able to run each nozzle and the fan all independently?

Quote:
Originally Posted by Bolt View Post
I think I am going to have to rewire a considerable portion of this, the fan starters are currently +/- 200 feet away, thermostats run them that are 100 feet away, and I don't feel like running 1000 feet of wire to make it work! But this is all starting to come together in my head, and it should work great.
You could also take temp control into this program, get a temp sensor connected to the PLC, and then do away with the existing thermostats...
course that's more code and more troubleshooting...

One other thought would be one of these:
http://web4.automationdirect.com/adc...Graphic_Panels

or one of these:
http://web4.automationdirect.com/adc...ls_(all_sizes)

The first one has free programming software; the second can be made to do all sorts of very cool things

Last edited by markttu; 06-02-2007 at 01:17 PM.
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  #27  
Old 06-02-2007, 01:14 PM
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Mark, it might just be me but that second link didn't work - got a "this page does not exist" message.
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  #28  
Old 06-02-2007, 01:17 PM
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It should work now; misplaced )
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  #29  
Old 06-02-2007, 01:51 PM
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I'm Glad someone knows what they are talking about. Cows I think.
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  #30  
Old 06-02-2007, 02:04 PM
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Quote:
Originally Posted by markttu View Post
Shouldn't be too difficult, but it'll probably put us over the 100 byte limit for the free version of the programming software. Currently its got an on/off switch, but no hand. If you do want to do hand/off/auto then in hand will you want to be able to run each nozzle and the fan all independently?
Yeah, we may end up over 100 bytes on this by the time we are done. How much is the real version of the program?

Quote:
Originally Posted by markttu View Post
You could also take temp control into this program, get a temp sensor connected to the PLC, and then do away with the existing thermostats...
course that's more code and more troubleshooting...
That was my next question for you that I thought of after I posted, I bet one thermometer could do everything.

My solenoid valves are 24VAC, I have plenty of transformers to provide this input for the PLC and relay to the valves.

Putting some more thought into this all, I have come up with a list of scenarios, and then a novelty.

This may get to being a little lengthy and wordy:

Scenarios

Outside Temperature reaches 75°F
Fan group 1 comes on, stays on until temperature drops below 65°F, or until 1:00AM (next day), whichever comes first. Fans run 100% of the time, no interval, as long as an external signal is present (milk signal, meaning there are actually going to be cows under the fans). Milk signal will go on and off before 1:00AM, but it’s not meant to have cycle stop for the day when this happens. Also, another 24VAC signal is sent to another output, which is used elsewhere. This signal needs to have Hand/Off/Auto. Also, a H/O/A switch for fan group 1, auto being time and temperature controlled.

Outside Temperature reaches 85°F
Fan group 2 comes on (group 1 is already on) and stays on until temp drops below 80°F, or until 12:00AM, as long as an external signal is present. Fans run 100% of the time, no interval. H/O/A switch for group 2, auto being time and temperature controlled.

Outside Temperature reaches 90°F
Water cycle comes on for 1 out of 10 minutes, fan go to corresponding 9 out of 10 minute intervals. The crowd gate position determines how many of the solenoid valves are activated. This program can continue until temperature drops below 80°F or until 12:00AM. H/O/A switch, auto being time and temperature controlled. Hand mode still runs the 1/10 cycle, and gate position valve controls.

Master H/O/A switch, auto mode coming from the milk signal.

Novelties


Fan group 1 comes on for 5 seconds before fan group 2 comes on. This situation would happen many times, whenever the fans come on in the water cylce, and when they are on 100% and have turned off by interuption of milk signal.

Temperature above 80°F, opens a contact. Stays open until temperature drops below 65°F.
H/O/A switch on this.


Questions

Are there way too many
H/O/A switches to program, would it be easier to wire them externally?

Is this becoming a very difficult program? I obviously need all the parameters to be tweakable, the times and temperatures.

Would it work to use a Dell Axim as means for programing the PLC, or is this more trouble than it's worth? Believe it or not, I don't have access to a laptop. Have 3 desktops and 2 handhelds in the barn, but no laptop. The PLC is 250+ feet from a PC, and it would be a difficult run to get to it.

My current PLC's have a small LCD module with 4 buttons for programing, go into the data register, find the D/R in question, and adjust value. But this PLC is all about running a timing program after a start signal is pushed, not too many inputs involved in this one to be tweaking. I am even so cheap as to only have one module for 2 PLC's, need to kill the power, pull it out, and put in other one and re-energize, just to adjust something a few seconds.
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