Author Topic: Mini plc,,,using avr(atmel)  (Read 6390 times)

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Offline jayris

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Mini plc,,,using avr(atmel)
« on: July 17, 2012, 11:28:55 pm »

plc cost is high,,,this is alternative,,,,any one try this?





http://www.waltech.com/site/index.php/open-source-projects
 

Offline olsenn

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Re: Mini plc,,,using avr(atmel)
« Reply #1 on: July 18, 2012, 12:34:09 am »
This looks like it will be fine if you aren't looking for high speed logic and need to drawl a lot of current through the ouputs. This design will almost certainly be limited to the switching speed of the relays. I guess the real question is what do you need it for?
 

Offline Spikee

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Re: Mini plc,,,using avr(atmel)
« Reply #2 on: July 18, 2012, 01:20:34 am »
The industry uses plc because they are reliable , so they wont be cheap.
It depends on your application but you probably don't need a plc for it  , a simple microcontroller whit some relays , ssr will be sufficient.
Freelance electronics design service, Small batch assembly, Firmware / WEB / APP development. In Shenzhen China
 

Offline Bloch

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Re: Mini plc,,,using avr(atmel)
« Reply #3 on: July 18, 2012, 10:55:05 pm »
plc cost is high,,,this is alternative,,,,any one try this?




http://cq.cx/ladder.pl
Quote
Of course a microcontroller with this software can't do everything that a PLC will. Most PLC environments offer more features and predefined blocks than my tool does. The PLC hardware is better too; usually the inputs and outputs are designed to withstand incredible electrical abuse. You can get a PIC16F877 on a carrier board for ten or twenty USD, though, and you'll pay a fair bit more for a PLC with the same capabilities.

So far I have received very few bug reports compared to the number of people with questions or feature requests. There is still great possibility for defects, especially in the targets for microcontrollers that I do not physically have (and therefore cannot test). Certainly do not use LDmicro for anything safety-critical, or anything that would break something expensive if it failed.


No i have not and will not use it for "work"


PLC is getting much cheaper today. If you are willing to look some of the "new" players on the market. Pls ask if you want more info on the plc i use at work.

 

Offline bilko

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Re: Mini plc,,,using avr(atmel)
« Reply #4 on: July 18, 2012, 11:07:02 pm »

plc cost is high,,,this is alternative,,,,any one try this?





http://www.waltech.com/site/index.php/open-source-projects

It's probably OK for home or 'hobby' work but in industrial applications it is a non starter.
This is because in industry, machinery must run 24/7, spares must be easily available. Most organisations want to standardise on one universal system that can cater for tiny projects to complete factory automation. They do not want to re-train for each quirky system that appears.

So it really depends what you want to do, getting customer acceptance is virtually nil because of the lack of support and spares. Using it in a school would be OK as it would give users a taste of limited PLC progamming.

 

Offline Bloch

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Re: Mini plc,,,using avr(atmel)
« Reply #5 on: July 18, 2012, 11:31:56 pm »
Using it in a school would be OK as it would give users a taste of limited PLC progamming.


That like learning to do assembler on a windows PC.


I know that ladder still is in the IEC 61131 but pls. learn ST, SFC and FBD.
 

Offline bilko

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Re: Mini plc,,,using avr(atmel)
« Reply #6 on: July 19, 2012, 02:01:42 pm »
Ladder is still the easiest for maintenance electricians to troubleshoot.
Reducing down time is the goal for most industrial facilities, its OK writing fancy code in ST, FBD e.t.c. but if it requires an expert to diagnose a problem then its very expensive to industry.

On the other hand, well written code written in ST and FBD should be as good as the PLC internal functions. No need to debug that code because it should have already been debugged.

I would consider using the ldmicro  in home or personal projects, but in industry, no way.

 


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