Thom Stewart wrote:

Doug,

I'm an old Petroleum Worker. 60V is to capable of creating a spark hot
enough to Blow the Place up.


Yes, but these systems are (were) used in other potentially
flammable environments.


We did, however, use 25 Volt, 5 to 25 ma Instrumentation on the New
Refinery out here.


Yep been there done that too.

A Comment to satisfy ASA; I transfer out here because of my Pneumatic
Background, That is the reason for the name of my boat; "Pneuma" I had
to have an Air powered boat!! Also; Pneumatics have yet to create a
spark in an explosive environment.


Navy steam plant automation was pneumatic. That's what I
started on.

Our Instrumentation out here was basically "Rochester Analog" with
Fischer pneumatic driven control valves. Signals to "Big Blue" IBM
computer for accounting. It wasn't long before we upgraded to total
Digital, Followed rapidly to 100% Computer Control. However the same
old pneumatic valve are at the end of the control circuit.


Have you retrofitted optical position controllers on them?
They're the bee's knees, simple bulletproof and no
mechanical linkage. You can adjust the proportional band
from the control booth!

Autologging rocks. I am almost at the point where I can
simply phone in calibration from home... or from the boat!


My gang called me; "The Old Huff & Puffer" and I called them; "Wink,
Blinkers & Nodders" I called my Venture 2-22 "
"Huff & Puff"


I worked with a couple of guys nicknamed 'winken, blinken, &
nod' they liked to go hide in the plant & snooze. One of
them once get angry with me for not hunting him down &
waking him up when his shift was over.

Regards
Doug King