How do I fix this?

[gar]

161228-2412 EST

PLC is an acronym for Programmable Logic Controller. Invented in 1968. See http://library.automationdirect.com/history-of-the-plc/ .

Fundamentally it is a special purpose computer with a resident program that interprets a special programming language that allows the application program to be viewed as one would view a relay ladder logic diagram.

Gaging equipment I built in the fall of 1971 for a Buick differential assembly line had the machine controlled by a Modicon 084 and thus also interfaced with my gaging equipment.

I believe that the term PLC is tightly linked to Ladder Logic and today with added functions. But still generally viewed as ladder logic.

I don't believe the name PLC should be associated with some other computer language that is not based on ladder logic. Doing so just muddies the definition of PLC. Embedded or special purpose computers with some other name should be applied to such systems. My gaging equipment of 1971 was a special purpose computer with its own programming language and was in no way a PLC.

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[zbang]

I believe that the term PLC is tightly linked to Ladder Logic and today with added functions. But still generally viewed as ladder logic.

I don't believe the name PLC should be associated with some other computer language that is not based on ladder logic. Doing so just muddies the definition of PLC.

I'm with you there, and having delved into far too many computer languages (30? 40?), I've never run across one called "PLC". (There are PL/I and PL/M, but those are rather uncommon now.)

 

[iwire]

Call it what you want, I will still call them a type of PLCs because that is what they do.

I don't see the choice of language used as meaning much

A human is still a human regardless of what language they speak.

 

[Johnnybob]

The older software uses the old 9 pin ports that are no longer on most laptops. The USB to SERIAL conversion from AB was about $450. Worth the money if you have need.

I have a USB-Serial adapter from "BLACK BOX" that cost about $20. I used it a couple weeks ago to get my laptop online with a PLC-5/20. Be happy to sell it for $400, what with mark-up and what not:angel:

 

[Johnnybob]

Correct, when I replaced photo-1 the LEDs on it and the input at the PLC changed state instantly when blocked and unblocked with my hand.



As I did explain above now with photo1 replaced when a bin breaks the beam of photo2 all motors stop and cannot be restated until the bin is removed from the beam.

Previous to my arrival and replacement of photo1 the machine was delivering bins nonstop and breaking the beam of photo2 had no effect on the machine.





I do not know.



Photo 2 changed state but had no effect on the machine previous to the replacement of photo1

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Which was why I asked about that limit switch. If PE 2 now stops it,maybe it's waiting for a bin to be offloaded fron the conveyor before loading another?

 

[Johnnybob]

Could you edit this image to show the locations of the photo eyes in question? It sounds like they would be to the infeed of the vertical conveyor. If so, is it possible that the bin stops @ P.E. #2 until a bin passes by a photo eye at the bottom so the machine knows the vertical conveyor is empty?

This is the first time I've been able to see this picture, and it makes a little more sense. If I missed something and reppeating a question, I appologize, but is it possibly waiting for another bin to load? As in, load a bin, it clears PE 1, then stops at PE 2, if you make PE 1 does it start again?