Re: [CAD_CAM_EDM_DRO] PLC's and industrial automation

> The wrinkle is that the size of each of the custom pieces was known
> only shortly before, by a process futher down the line. Therefore, the
> requirements were to be (dynamically) sent via ethernet to the pc
> doing the cutting. I presume an advanced PLC could do this (read
> from an ethernet, and change its behaviour appropriately), but I
> don't have any experience with PLC's.
>
> OK - lets hear from the PLC experts (maybe a short tutorial).
> What is all this 'ladder logic' stuff? Is it programmed serially
> into a static memory? ... or ?
>
> Doug Fortune
> http://www.cncKITS.com

Ladder Logic: Think of a programming language that only allows you to use
statements like IF, OR, AND, NOT and THEN. To make it even better, all of
this happens in an endless DO loop. Now, each time the PLC does a loop it
reads the state of the inputs and does its IF-OR-AND-NOT thing and THEN
updates the outputs.

Well, I sorta kinda left a few details out, like timers, counters and a few
other helpful thingies. Learning it is like staring at one of those optical
illusions. Its just nonsense until BAM! and you get it.

I think your cutting example could be done with the $159 version of the
DL-05. These things are amazing. We put one in a machine once because it
was cheaper than buying eight separate relays - bought it just for the
built-in relays. I decided to eliminate the SSRs on my CNCpro interface
board for the same reason.

Doug Harrison