plc programmer needed

tomz

I hope I'm posting in the right spot.
I am working on an Idea and I could use a plc programmer in the Stockton, Ca. area.
Example of what im trying.
Say you had a log splitter, and you had an electronic indicating pressure switch/ transmitter installed in the hydraulic port to read pressures.
Say you are splitting soft pine all day and your pressue is 500psi, now you put oak in it and the pressure spikes to 800 psi. Can a plc stop the splitter and sound an alarn say @ 650 psi.
I hope I make sence.
I dont know much about this stuff, but would like to talk with someone in my area.
You can e-mail me @ tbmenuitem20@gmail.com
Thanks

pacman

I'm not in CA, but I can answer the question.

Yes.

Exact configuration would depends on the how adjustable you want the pressure 'limit'

If it needs to be adjustable then you would need a PLC with one analogue input (for the pressure input) and one digital output {for the switching/alarm) + perhaps some sort of display to show the pressure and allow the adjustment. This is provided you want to adjust 'stuff' by PLC, some transmitters have the ability to adjust trip points on the instrument.


If the pressure was just a set point (didn't need to be adjusted or can be adjusted on the instrument) then a pressure switch {set for 650 bar} could be used


Depending on what else you need to do, ANY shoebox PLCs would eat this application - many would be massive overkill.

A hydraulic switch, a motor contractor, a yodalert and a contact block would would probably do the same thing - and may be much cheaper....



HTH.

Paul

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Post Edited (pacman) : 5/17/2010 2:01:52 AM GMT

tomz

Thanks Paul
Would it also be possible for a plc to pick up a normal operating pressure, say after 5 cycles of the ram and program itself to shut the splitter down if a pressure spike comes along during normal operations?
I need to have variable operating pressures, but would like to auto set my cuttoff pressures if possible.( like say the unit could calibrate itself after so many seconds or ram strokes)
I do understand that going the plc route may cost more, and I have read a plr may work as well.
The equipt. this is going on is in rugged use constantly as well.
Thanks again for your time
Tom

tomz

One thing I forgot to mention. I have a Noshok brand switch, it is a series 800, If some one wants to have a look at the specs on thier website to see if this can be used in this app. that would be great.
Thanks

erco

@Paul: Is a yodalert related to a snipe? Dunno nuttin' bout no yodalert... but now I know I need one.

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·"If you build it, they will come."

pacman

@erco: I'd be more needing a Darthalert .

Seriously (for those that don't know) a yodalert is a very loud type of siren - yodalert is a more 'generic' name - a PDF of a typical unit is here www.signaltech.pl/files/file/yo-3-5-en.pdf.

That's not to say that simple buzzer wouldn't work in this application (just I think of all industrial applications that use a buzzer/siren/hooter/whatever as a yodalert)

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
=================
The future is in our hands.
Which way to the future?
=================

Post Edited (pacman) : 5/17/2010 2:02:59 AM GMT

pacman

tomz said...
Thanks Paul
Would it also be possible for a plc to pick up a normal operating pressure, say after 5 cycles of the ram and program itself to shut the splitter down if a pressure spike comes along during normal operations?
I need to have variable operating pressures, but would like to auto set my cuttoff pressures if possible.( like say the unit could calibrate itself after so many seconds or ram strokes)
I do understand that going the plc route may cost more, and I have read a plr may work as well.
The equipt. this is going on is in rugged use constantly as well.
Thanks again for your time
Tom

Getting more complex, so a PLC is starting to sound like a better fit (though nothing precludes just instruments and wiring at this stage, especially seeing at the instrument has the ability to have set-points programmed into it).

However, a simple PLC with some sort of screen could do all sorts of other stuff. One of the guys on the forum even has a unit that could perhaps be used Peter Jakacki www.cescom.com.au/products/products.html.

You could have a screen that allowed you to select the type of log (and this would then govern the set-points), display the last {say} 5 'log split' pressure values, how long it's allowed to be 'outside' of the set-point, total operating time, time, date, all sorts of good stuff...

Depends on the budget and your specification. We could built it for less than $200.00 or more then $20,000.00.

Think about what it needs to do, and how the operator interacts with it - then we can come up with some more 'better' solutions....

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=================
The future is in our hands.
Which way to the future?
=================

kf4ixm

Check out DirectAutomation plc's, i've used alot of these in the past and are relativley cheap compared to allen bradley's.

the microbricks should do what you need, found here...

http://www.automationdirect.com/adc/Shopping/Catalog/Programmable_Controllers/DirectLogic_Series_PLCs_(Micro_to_Small,_Brick_-a-_Modular)/DirectLogic_05_(Micro_Brick_PLC)/PLC_Units

you can add either a 4-20ma input card or a 0-5vdc input for your pressure input, depending on the sensor you use. they also have operator interfaces avaliable for changing setpoints or diplaying other data. they also have sensors avaliable too, if you like one-stop shopping.

tomz

Wow!
I have been looking forever for answers, and I will check out these suggestions.
Please remember, I have no biz trying this plc stuff myself, I really could use a buddy in this field ( I thank you all )
Since this app. needs very few functions, could I get by using a plr?
Tom
This stuff makes my teeth hurt, in a good way.(he he)

kf4ixm

As far as i know, there isn't a plr that has analog i/o. if you use multiple pressure swiches for the different pressures, you could use a plr. i would advise against changing the setpoint on a pressure switch alot as it can be very inaccurate and fail over time. analog i/o on a plc would be the way to go.

tomz

Thanks kf4ixm
I will only use one pressure switch.
Would a plc be able to pick up on an operating press. and adjust itself to switch off hyd. pump when press. spikes to say 10% over normal op. press.?

kf4ixm

yes, a plc can do that with an analog pressure sensor, all you have to do is program your logic to control a relay on the plc to open once a certain pressure setpoint is sensed. for the hydraulic pump, i would have the relay output control a motor contactor to operate the pump, as most plc internal relays can only handle a couple of amps. you can program multiple setpoints also with simple switch inputs for your different pressure setpoints, say switch input one would be for 500psi max, another for 650psi max, etc.

tomz

Thanks again Kf4ixm
Do you think I could find some help at the local collage?
Should I check with the Mech. eng. dept.?

kf4ixm

yes, you could check with a local college, see what they have, or if you know someone in industrial maintenance with a strong control electronics background at a factory nearby you, they could probably help you out too. Good luck!