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PLC for use on a house? How could you use it? 2

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bdn2004

Electrical
Jan 27, 2007
794
Like the previous poster asked...I've often thought about buying a PLC just to learn the basics of programming, there is nothing like hands-on.

And there is also nothing like having a goal in mind. I often thought about monitoring my fence so that I know if somebody opens it...and then kick on a camera,...put a power monitor on my service... .

Any other ideas? The place I work has Allen Bradley everything.
 
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Check out automation-direct and their click PLC's. They also have some inexpensive current transformers and other sensing devices. I work at a Rockwell and Mitsubishi plant and I like their stuff, but cannot afford to buy the software and hardware for home projects. The click PLC software is free and the hardware cannot be beat for the price. Take a look.
 
Hello!

If you need a PLC system you could try some compact PLC(like S7-200 from Siemens,CP1 from Omron,MicroLogix from Allen Bradley) but the price could be 1000 euro with HMI.

The cheapest way is to try a programmable logic relay like Logo from Siemens,Pico from Allen Bradley,Easy from Moeller-Eaton...The price is about 100-200 Euros.

Best regard!
Venix
 
Perhaps make a home security system?
 
I have a cabin in the mountains that my kids and friends use during the winter. Problem was everyone forget to turn down the heater, turn off the water, etc. Utility bills got high, I had some stuff around, so I used a Micrologix 1200, a modem I had, and other bits and pieces. I can call the cabin, turn up the heat so when the wife and kids go up it's not too cold inside, fire up the hot water, turn on the water, etc. Was a nice project, my son learned a little about what some of the "junk" in the garage can do, my wife stopped complaining about said junk after she saw the bills the next winter.

I don't think it would be a viable project if you had to pay full price for everything, but between Ebay and some industrial surplus houses you might find enough to put something together to learn with and provide something you can really use.
 
you could also use a plc to trend pressures and temperature in your place as well. Would give you some practice with analog signals too.

 
A colleague is setting up a multiple zone temperature control in his house. He is using an RTD on each floor and controlling his burner, a couple circulation fans and water circulation around his radiators.
 
Thanks for all the good ideas...links to exact types of parts to buy (temp sensors, ct's, power monitor's etc) would be even better!
 
I have over the years attended several workshops where small PLCs are provided in the workshop price. I used one as a "glorified" sprinkler system controller, another one for my holiday light displays. I have a lot of fun with it.

My latest acquisition is a new Siemens S7-1200 micro PLC with a small touch panel (Siemens is promoting these heavily right now, look for workshops where you can get a PLC + HMI for around $300). I plan to use it to control an old VFD I have running my water feature (fountain / pond). My plan is to rig it with a hidden prox sensor so as people get closer, the speed increases and if they get too close, it randomizes to the point of possibly getting them wet!


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This guy's review of the linked book tells of all the good ideas the author demonstrates in his book.

The book details how to automate using a PLC with Visual Basic. I would think VB would have a lot more opprotunity to make the home automation user friendly instead of using ladder logic to interface with it.

"As a home monitor the PLC will monitor the following digital inputs: front doorbell pushbutton, rear doorbell pushbutton, front door open sensor, rear door open sensor, first floor HVAC system on, second floor HVAC system on, water pump on, and mail box open sensor. In addition to the discrete digital inputs, five temperatures will be monitored (outside air, crawlspace, first floor, second floor and Great Room) and water pressure of the water pump will be monitored. Two PLC outputs will be used to drive a horn and turn on a blower fan under the control of the Visual Basic program."

 
Check out automation-direct and their click PLC's. They also have some inexpensive current transformers and other sensing devices. I work at a Rockwell and Mitsubishi plant and I like their stuff, but cannot afford to buy the software and hardware for home projects. The click PLC software is free and the hardware cannot be beat for the price. Take a look.

I bought one for a project at work, it was extremely cheap (as PLCs go) and it was a cinch to program. I downloaded the *free* programming software and had my program written in just a few hours. It was simple. :)

The software is great, I'd say it's better than anything from Rockwell. Or GE, or Siemens...

And a few weeks ago, I received a registered letter from AutomationDirect informing me of some serious programming errors in the Click software and that I needed to download the newest version and reload my software using it.

I've rarely been notified before about a software/firmware problem let alone getting notified via registered letter!

Usually the only time I'm made aware of a problem is when I have to escort the factory reps to do some "midnight upgrades". :)

And who else has a PLC for 69 bucks?
 
jraef

Interesting approach; wonder which seminar it was you took? There seem to be as many S7 ones as there are competing PLC's.

I've starting in on finding a PLC to sequence/control a backup power system in a house -- about 10 inputs and 10 outputs. (The last time I even looked at the field, they were built with TTL, so it's been a while.)

It would be nice if the system would let me remote several of those at the far end of an Ethernet connection.

 
I used a Modicon 984A some years back. I had four 800 series remote I/O drops located in various buildings around my property. I used it for a burglar alarm, a lawn sprinkler system, swimming pool control, hot tub control, water heater control and various other uses such as flood light, fencing/gate control. List price, this system would have cost in the tens of thousands of dollars. When I wanted to sell the house, I had to convert all of the systems to more "normal" individual control schemes so that they could be maintained by the new homeowner.

Bob
 
>When I wanted to sell the house, I had to convert all of the systems to more "normal" individual control schemes so that they could be maintained by the new homeowner. Bob

My Dad ran into the same situation with a solar house controller he built in the mid-1980's. The solar mechanics were copied from a colleague's house. The colleague made his own 'embedded' solid state controller, basically thermocouple inputs, TTL timers, real time clock and outputs all laid out on a printed circuit card. He had a learning curve when lightning took out board after board.

My Dad did his controller in discrete relay logic, a few timers and some then-current HVAC components (a time-of-day/day-of-week set-back thermostat, a couple capillary bulb thermostats, electric actuators).

The colleague died, his estate went to sell the house and could not get a nibble with its unique, one-of-a-kind heating controls. The estate eventually hired my Dad to replace the original embedded system with a replication of his discrete HVAC/relay logic controls.

No local heating/AC firm would touch the embedded system. A couple have since done work on the replacement discrete relay logic.

 
danw2, I believe that!
No way the average HVAC, burglar alarm, lawn sprinker techs or the average electrician would have any idea on anything like this. It's great when you have it for yourself, but it takes a real interest in these systems to have them in a home. Unless you can afford to pay someone like us to maintain it! LOL! Maybe Madonna needs a system.....

Bob
 
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