Irrigation

This may sound like a dumb question to all of you experienced programers out there but ... where can I buy Siemens LOGO's from besides Ebay and direct order. I work for an irrigation company in Nebraska and I am trying to get some PLC's put into the main control panels. I worked with the micrologix and LOGO both in college and feel that the LOGO is a better choice due to simplicity and cost. If anyone has any advice please reply or e-mail.

Many thanx,
Lucas

I'm not trying to change your mind, but your evaluation criteria might be a little off. There is a lot more to selection than simplicity and cost - it those are your only two criteria, sooner or later, you'll be sorry.

SOme other questions to be answered:

What tech support is available in your area? This is a very improtant question, don't underestimate it.

What is the availability? Is there a local distributor? (Nothing worse than being down for a week because someone wanted to save a buck)

Is the local distributor service oriented? The local AB distributor here is very service oriented and they know their stuff. The local Modicon distributor is no more help than a rock, and not much smarter. (Not surprisingly, he doesnt sell many units either) I have both kinds of machines so I have to deal with both. What are the distributors like? It matters, and it matters a lot.

Is there someone else (an integrator?) in the area that knows the PLC you choose who can bail you out if you get in a real bind?

There are other excellent PLCs as well that may be easily available in your area with a good local distributor who knows his stuff. Just b/c there isn't a Siemens or AB distributor nearby does not mean there is not a Mistusbishi, GE, Omron, Modicon distributor.

Lucas,

What are your specific requirements?

As Alaric mentioned previously, there are many possibilities available to you.

What level of support will you require? Some companies sell on a direct basis, some require you to go through distribution only.

When selecting a product, you are selecting a partner. You will need to take into consideration:

- Cost of software
- Level of support; warranty; phone support
- Hardware

Not all manufacturers are created equal.

Hope this helps...looking forward to learn more about your needs.

Please note that I am a representative for a PLC manufacturer.

God Bless,

I am not partial to smart relays so would not suggest using a LOGO or another brands counterpart. These days you can buy a PLC for less than most LOGO type controllers. One company that you can order online that has a $99 PLC (and more) is www.automationdirect.com. They also have numerous other components that may be of interest.

As Alaric stated dont look at price first, look at what will fit the applications the best. Note that AB also has the PICO which is basically the same thing as the LOGO, they also have a 10 point Micrologix for $99 with free software http://www.ab.com/plclogic/micrologix/1000/
AB also offers online shopping.

Stephen mentioned being a rep for a PLC company, the website is www.entertron.com They offer a micro plc with free software plus several other items in this area.

If you can work with surplus items (new or used items at half price) then take a look at www.plccenter.com

I would also suggest you talk to the local distributors to see what they can offer.

If you do not have a local distributor then I'll echo Ron's recommendation to look at automationdirect.com. As long as you dont have any heavy floating point math their small end PLCs might be just right for you - and they have excellent phone tech support. Replacement parts are just 24 hours away.

On the other hand, I was one of the first big promotors of the "Smart Relays", when Moeller (K-M) first introduced the "easy" relays. I have gotten somewhat away from this, but have engineered up some wild units in recent years, since the advent of the expansion modules and psuedo "networking".

But then, I am a big fan of some micro plcs, too!

Having down countless irrigation panels of all sorts over the years, I think that I too would favor the small PLC. Ron has mentioned the ones that I would.

The small Allen Bradley unit is just that, small. But it might fill your application, specially for 110 volts. Most irrigation projects that I have seen are a little light on voltage, out in the fields, with way too much way too small wire.

Entertron's Smart Pak series of small plc's come in 12 and 24 volt DC versions, with relay outputs. Software and Tech Support are free. A variety of options, including analog, are available. I have wrote several programs for engine and pump controls for this model. I think that you will find it well suited. These would be my first choice. Their warranty is hard to beat!!! I haven't needed it yet. Their products take their fair share of abuse. I help with a machine using one of their larger plc's that is located in Canada. It is older, and the control panel has been on a couple of other machines. It has held up quite well!

I have wrote a couple programs for the little AB unit for pumps, but it is not conducive for engine controls.

I was able to do some with the Automation Direct units several years ago, but ran into some problems with acceptance by a couple of customers. I found the programming on their DL05 not to my liking, but I was spoiled at the time using GE products.

I like the GE micros, but they are higher in price, plus the software is extra. You can get around the software issue though, with a Tool Box Kit from a local good distributor. If none is available, I can put you in contact with one in the midwest.

regards.....casey

When I joined this forom I was Omron and AB fan.Here I read about AD.

I never used local support here in Israel.
AD book are very clear and understandable.
also the support over the phone is great, add on line seminar and the support of this forum.
From other hand if you are not so patient
get something local where you can get support and help close to your location.or on site.
You need to decide how much time and money you want to spend for that.

Stephen,

I've got an application that may be forthcoming. Do you have any lit on your line of PLCs?

Thank you.

thank you for the help

First,
thank you all for the helpful informationt that you have given me,

Second,
my application is relativaly simple, I am simply trying to replace about 3 timers and 4 cube relays, nothing to challenging for any unit I wouldn't think.

the reason I talked about the LOGO's and Micrologix is because that is what I worked on in college and what I am familiar with, I am willing to learn any new program though if I can find a distributer in my area. Also I am still in touch with my instructors from college and they offer me advice if I get myself in to deep. So thank you all again for the help and hopefully I can find some good info on the websites some of you have listed for me.


Great thanks to everyone,

Lucas

Has anyone automated a irrigation pivot with a plc and used an endcoder to get the direction of the pivot?
Thanks

Andrea with a quadrature encoder that would be a simple task. Depending on how sophisticated your need, the plc and encoder can show direction, speed and how many times it has rotated in a specific direction over a given time period. Depending on the application it could be setup using 360 degrees and rotated in different methods...ie from 100 to 300 degrees and back to 100 degrees, a swivel action ....JUST DEPENDS, the only limits are your imagination and the Law of Physics.

I have not done this in an irrigation system but I have done something similar for a (sort of) water display.

I don't know anything about a endcoder, So I am wondering, can you set the endcoder up that if in 4 360 revolutions it would give me a 1 360 turn? What i am trying to say is, if the pivot is facing north and it would make a 360 deg turn but the endcoder had ro make 4 revolutions or 10 revolutions can I work it this way, or is it 1 to 1
Thanks

CropCop,

Without changing the focus of this thread, I will be brief.

All information is available on line at our web site. Link in my signature.

There is a product recommendation form that you can complete and email to us.

I have also sent you a private message.

I look forward to working with you.

God Bless,

Irrigation controller

Lucas hi,
I don't want to spoil your fun,but you can buy a ready made irrigation controller.
Go to http://www.galcon.co.il/index.asp

Steve

Andrea encoders have different pulses per revolution therefore you use what is needed, in some cases the encoder may turn multiple times before the "device" turns one revolution....the specifics depend on the application. Encoders come in different ppr, you use what will offer the best resolution for the application. In your swivel example all you mentioned was direction, a quadrature encoder has an A and B output which determines direction, the one leading gives direction. Speed or position is determined by the count.

A good encoder info site is http://www.motion-control-info.com/tech_support.html

Motion control info; http://www.motion-control-info.com/

This page offers a basic explanation http://www.motion-control-info.com/encoder_design_guide.html