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Can I replace PLC with microcontroller for project

Minder

Apr 24, 2015
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A PLC has essentially a micro controller as its core, the difference is that the PLC has all the I/O conditioned with Opto modules etc.
Another nice feature of a typical PLC is that the (ladder) logic can be displayed on a PC screen and the (on/Off) condition of each I/O can be seen.
You could however make up I/O using Opto22 modules etc.
A micro should be equally as efficient, if not more, as a PLC has an update time taken to update all I/O conditions table.
M.
 

Nanren888

Nov 8, 2015
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Some PLCs do a lot of conditioning of inputs for you. For example, you tell it that you only want to create an event when some signal changes beyond a particular amount, or out of some control zone.
Some also have support for various commonly-used functions.
The standards define multiple ways to programme them, ladder logic, structured text, often something that looks like microcontroller assembler, but runs on a virtual processor.
That hardware signal conditioning that Minder mentioned, opto isolation and often filtering is often really useful.
So, in a similar way to Minder's answer on the hardware signal conditioning, nothing that one can't implement oneself, but often a PLC is a very convenient way of doing it all with a minmimum of work.
There are some really small PLCs by the way.
 

Bluejets

Oct 5, 2014
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Old pc system that I use for a crank grinder for miniature engines.
Might be useful for reference so you can get some idea of the complexity of starting from scratch so to speak with a uC.
 

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Minder

Apr 24, 2015
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A PLC should be perfectly capable,
The operation appears to be a point-to-point procedure which is well within the capability of a PLC.
An issue often appears when servo positioning is required, especially if interpolated moves are required.
Some PLC's have add-on modules to take care of this, but gets expensive.
M.
 

Minder

Apr 24, 2015
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It' seems PLC is not efficient for the project
If your concern was because I mentioned the relatively lower I/O refresh rate for the PLC, it would inconsequential, especially in this application.
M.
 
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