Driving Out the PLC

Moose

Because the variety of wire sizes had to be considered, this operation was a two-step deal. The operator had to reprogram the PLC to work with the materials at hand. The new controller eliminates that particular job of the operator; and in that sense, is a great addition/replacement of the original system.

And this is because such decisions are not the job of PLCs. A PLC is basically a start/stop controller with parameters that determine the starting and stopping situations. For their purpose, they are simple and efficient, and easy to programme.

In many, if not most, of the areas in which PLCs are used, having the sophistication of decision-making based upon extenuating circumstances would just be adding unnecessary equipment and expense.

So, when the title of the blog reads "Driving Out The PLC", I have to ask what would be gained from getting rid of them?

Mark

Yes,

your statement are 100% right. Few years back for taking the signals from one place to another place we have lot of cables we are used. But now days we have lot of communication systems. These communication systems are works with PLC. Based on this communication system We don't use more cable for transferring the signals.

Meaning no disrespect to anyone but it sounds as if the original installation was perhaps lacking. I don't see why an operator would have to do manual calculations when you have a computer right there, the PLC. Maybe it was an older, very simplistic PLC but I have designed traverse winders with PLC's in which all that is required is to enter material width, gap width (space between material), and a few others that in this case would probably never have to be adjusted. There are no calculations or look-up tables required by the operator, just entering physical constraints on what they want.

I see nothing wrong with the way that it was implemented and it may be a better solution for this manufacturer then a PLC based solution. But it certainly could have been done with a PLC with the same results.

Shawn

Shawn33

The way I understood the blog, there were several different diameters/types of wire for several different applications being manufactured. The PLC was used in the control process for manufacturing the cable.

Until they installed some kind of computer-run remote installation robot to determine which molds/insulators/etc. to draw/run the wiring through every time the line was changed to accommodate some customer's wiring specifications, a setup person had to be employed to do that job. After that, the process for each type of wire was similar enough that the PLC just ran the manufacturing machinery.

With the new system, the customer order specs are probably just punched in on a keyboard somewhere, and the line is automated to self-adjust according to a software program that can have infinitely more complicated decision-making possibilities/combinations/parameters than a PLC would normally be employed to make, PLUS run the production line. The range of possibilities and automation requirements formerly undertaken by their line set-up person would make the new system much more desirable than the old PLC for that purpose.

Anyway, that's what I understood from Moose's blog.

Mark