Re: The joy of FORTRAN

On 3/9/25 1:35 AM, rbowman wrote:

On Sat, 8 Mar 2025 22:57:22 -0500, c186282 wrote:
 

    A good question ... are 'solid state' relays always "better" ?
    Admittedly no contacts to wear out and quicker. DID encounter a
    situation once where the delay was a GOOD thing, made it possible to
    test a critical condition before the entire relay chain was engaged.
    Maybe not the best design strategy, but what was, was.

 We used a lot of octal base 120 VAC ice cubes. One problem as solid state
devices started to appear was the voltages and currents involved looked
like dry circuits as far as the ice cubes were concerned.
 https://www.trafficsignalmuseum.com/pages/ef15.html
 There are photos of a stepper toward the bottom of the page. They were
popular for industrial controls. Later models had pieces that you could
snap onto the cams rather than breaking pieces off that saved
disassembling the entire thing to replace a cam if you screwed up.
 Anyway hitting a limit switch would actuate the solenoid lifting the
massive lead weight which would then drop rotating the drum one position
bringing you to the next state.
 The company I worked for at the time went to a new design of vertical
hydraulic press where the ram was in free fall until it hit a limit
switch, closing a pilot operated check valve. Then the ram would be pumped
down at a slow speed. In theory. It worked fine in our shop. When we set
it up at the GE plant they filled it with hydraulic fluid that resembled
squirrel piss. On the trial run the ram hit the limit switch, the stepper
barely twitched, and the mold closed at full speed. Not good.
 I added a relay that was fast enough to react to the limit switch and
would then actuate the stepper. After that fiasco we went entirely to
relay logic and skipped the stepper.

   I've seen big mechanical 'steppers'. They have
   their uses. However there ARE alternatives and
   modifications.
   "Mechanical" systems have DELAYS - this can be
   good, made use of. Alas attempts to 'improve'
   them without proper understanding can also be
   a disaster. It's all designed as a "system",
   and 'upgrades' don't always get the nuances.

Footnote: years later and at another company we had a contract to build
the controllers for the sequenced runway landing lights and I got to meet
the stepper again. Since the GAO recently said the FAA is years behind
modernizing I'm thinking those 50 year old steppers are still thunking
away.

   Likely TRUE !!!
   Old tech is still everywhere. Alas the number of
   people who UNDERSTAND it and its reasons are now
   fewer and fewer.
   Kinda like those sci-fi things about old societies
   that run on tech that's near magic ... but nobody
   knows how it all WORKS anymore. First little flaw
   and it all crumbles. Back to sticks and stones IF
   you're lucky.