Productivity 2000 and Dairy Manure scraper

[Levi G]

Hi I am looking at monitoring a manure scraper to see if there is a cow down in front of it. This particular one is run on a hydraulic cylinder. The hydraulic cylinder moves in and out continuously, on the outward stroke the the cylinder moves the scraper ahead 3feet, pulls cylinder back in and repeats, when it reaches the end of scraper alley the cycle is reversed bringing the scraper back. The stroke is not controlled by the plc but by a hydraulic component.

What I would like to do is monitor each stroke and see if there is a sudden increase in pressure, as manure piles up in front of scraper the pressure goes up but only gradually. The extend pressure is about 600psi and retract about 900-1000psi loaded with manure.

Can anyone point me in the right direction as how to find the highest pressure on each stroke? THANKS

I am looking at using a Productivity 2000 for this project.

 

[Brandon_K]

Are you using this strictly for monitoring the one input? No other control? Are you using this to alert someone or to stop the cylinder?

While the P2K system is nice, it's entirely overkill for your use. You would be better served in probably every aspect (cost, space, cabinet size, program simplicity, etc) by either a analog Click, or if you need ethernet, a ethernet Click with an analog card.

Even the basic analog Click has two analog inputs, 12 bit resolution (which is good enough for a 0.5psi resolution on a 2000psi transducer).

https://www.automationdirect.com/ad..._(Stackable_Micro_Brick)/PLC_Units/C0-02DD1-D

From the program standpoint, I would do a few compare contacts and have them trigger outputs (or maybe a HMI) as needed. If you need something super basic, you're talking less than a dozen rungs of code.

 

[Levi G]

I will use the P2000 to do the cleaning of 4 alleys at certain times of the day as selected from a hmi (c-more) I prefer the p2000 over the click because it seems a lot easier to work with. (never used CLICK before)
I want the cylinder to stop if it were to sense a cow is down. I dont know of a way to determine the highest pressure when the when the cylinder is pushing and pulling. Maybe I could use a FIND MIN MAX VALUE instruction when pressure goes higher than say 700psi then use a FIRST IN FIRST OUT instruction and compare the average of the last 3 strokes to the next stroke. and then if the diff is too big then stop cylinder. Would that work?
Thanks for the help

 

[Brandon_K]

As far as the hardware, both platforms are great. In the last year we've gone through over 300 Click's with zero issue. The software is bug-free and super easy to use. We use quite a lot of P2K systems as well for more intensive tasks, if I'm using a lot of analog (P2K has far denser analog options) or I need logging.

I can typically write programs much faster with Click since I rarely need to touch the mouse, plus it's address based (vs P2K being tag based), so I can type in "C10" for a control bit, much faster than typing a new tag into Productivity.

They do have Click models with a real time clock, so you can still program based on time/day events. Programming with C-More is the same between the two since you can import the address database (do note, that you have to manually add all of the addresses if you're using C-More Micro. Micro's use a different software package that doesn't have the same range of features that the C-More EA9 software has. I use both)

I'm not trying to push you either way, but the Click will do everything you need it to do at 1/5 of the cost.

As far as your program goes, I think you're making it overly complex, in my opinion. You're dealing with a hydraulic system with known variables. You know that it's 600psi on the extend and unless something is in the way, it should never go over 1000psi. Under 1000psi and everything is happy. So I would do it in one rung. Click forces you to scale when you setup the analog input (which is fine for linear inputs, AD's SPTD25 transmitters are very linear and would be great for this application). In P2K, you'll need to add another rung for scaling. Either way, your scale would be 1:1

"Scaled analog value" > "1000" (psi) ---------------------OUT

I would probably drop a timer in there to account for any pressure spikes due something as simple as the initial valve opening, so unless the pressure is greater than 1000 for 500ms, it won't turn the rung true.

 

[Levi G]

:site:Thanks for the help. I think I will download the click software and see how it feels. I will be using C-more EA9-T7CL. Ethernet version. I`ll see if I can get a cow to sit down in front of it and see where the pressure goes to.

 

[Ron Beaufort]

just wondering - but wouldn't some type of photo-eye arrangement be easier and more reliable than monitoring the pressure? ...

I'll freely admit that I know ZERO about scraping cow manure - so feel free to ignore me ...

 

[kallileo]

That's a weird requirement that you have. We are in farming equipment and robotic milking business and I have seen many manure scrappers both hydraulic and wire rope working on farms. Usually the cows don't mind the scrapper and step over it or move away when needed unless they are lying dead in the alley. They should be lying in beds and not in the alley. So the farmer should get an advise from his veterinary.

But then such weird requirements provide us with work.

 

[Levi G]

That's a weird requirement that you have. We are in farming equipment and robotic milking business and I have seen many manure scrappers both hydraulic and wire rope working on farms. Usually the cows don't mind the scrapper and step over it or move away when needed unless they are lying dead in the alley. They should be lying in beds and not in the alley. So the farmer should get an advise from his veterinary.

But then such weird requirements provide us with work.

These cows don't sit in the scraper alley. But sometimes they will fall and cant get up anymore. Well sometimes when we bring in new heifer then these tend to sit in the scraper alley till they are trained to sit in a stall.

just wondering - but wouldn't some type of photo-eye arrangement be easier and more reliable than monitoring the pressure? ...

photo-eyes would not work as the scraper alley is about 200' long x 12'wide and cows step on and around the scraper all the time. not to mention that it would immediately get covered in manure.