Re: Rewriting SSA. Is This A Chance For GNU/Linux?

On 4/7/25 17:59, c186282 wrote:

On 4/7/25 4:39 PM, -hh wrote:

...
I had one project some time 'way back in the 80s where we were troubleshooting a line that had a 1960s era analog control system, and one of the conversations that came up was if to replace it with digital. It got looked into and was determined that digital process controls weren't fast enough for the line.
>
Fast-forward to ~2005.  While back visiting that department, I found out that that old analog beast was still running the line and they were trolling eBay for parts to keep it running.

    Hey, so long as it works well !

It did, so long as there were parts for it.

On another visit ~2015, the update:  they finally found a new digitally based control system that was fast enough to finally replace it & did.

    What was the thing doing ?

It was running a high speed manufacturing line.  If memory serves, roughly 1200ppm, so 20 parts per second.
For a digital system that's a budget of ~50 milliseconds total processing time per part, which one can see how early digital stuff couldn't maintain that pace, but as PCs got faster, it wasn't really clear why it remained a "too hard".
That seemed to have come from the architecture.  Its a series of linked tooling station heads, with each head has 22? sets of tools running basically in parallel, but because everything was indexed, a part that went through Station 1 on Head A, then went through Station 1 too on Heads B, and Station 1 on C, 1 on D, 1 on E, etc ...
The process had interactive feedback loops all over the place between multiple heads (& other stuff), such that if head E started to report its hydraulic psi was running high, that was because of an insufficient anneal back between B & C, so turn up the voltage on the annealing station...and if that was already running high, then turn up the voltage on an earlier annealing station.
But that wasn't all:  it would make similar on-the-fly adjustments for each of the individual Stations too, so if Tool 18 on Head G was complaining, they could adjust settings on Tools 18 on Heads ABCDEF upstream of G .. and HIJK downstream too if that was a fix too.
It must have been an incredible project back in the 1960s to get it all so incredibly figured out and well balanced.
The modernization eventually came along because the base machines were expensive - probably "lost art" IMO - but were known to be capable of running much faster, and it was finally a modernization to have it run faster that got over the goal line for digitization.  I think they ended up just a shade over 2000ppm; I'll ask the next time I stop by.
-hh