Jay R. Jeffreys, P.E.


PID, APC August 1, 1998

Looks may not be deceiving after all

Maybe I spent too many years working for a PLC vendor, or maybe I'm just skeptical. When it comes to a factory-floor control system, though, I'm more likely to be impressed by reliable, predictable behavior than by fancy screen displays.The people at Wonderware Corp. (Irvine, Calif.) have consistently delivered good graphical user interfaces for the application programmer as well as the e...

By Jay R. Jeffreys, P.E.
PID, APC June 1, 1998

Graphical programming for analog control

If it's true that just any old picture is worth a thousand words, then a detailed picture of a regulatory control strategies must be worth quite a few words of machine code, right? That certainly seems to be part of the design intent behind the control system software development package known as Gello, available from RTP Corp.

By Jay R. Jeffreys, P.E.
System Integration May 1, 1998

Structured programming for Quantum PLCs

As a system integrator I suppose I should love relay ladder logic. It lets me write long strings of code with no apparent structure which only I can maintain and extend. There is no greater sense of job security than knowing that clients must call me back in any time something goes wrong with the code.

By Jay R. Jeffreys, P.E.
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