PID Loop Tuning

In your recent "How Software Tools Simplify Loop Tuning" article [Control Engineering, Nov. 1997, p. 89] you imply that ExperTune connects only to PLCs. ExperTune has a DDE connection that connects directly to Fisher/Provox (via SIU, HDL), Honeywell TDC systems (using GUS workstations), and Bailey DCS (via SIU).

John Gerry

In your recent "How Software Tools Simplify Loop Tuning" article [ Control Engineering , Nov. 1997, p. 89] you imply that ExperTune connects only to PLCs. ExperTune has a DDE connection that connects directly to Fisher/Provox (via SIU, HDL), Honeywell TDC systems (using GUS workstations), and Bailey DCS (via SIU). For single-loop controllers ExperTune also has a standalone data acquisition unit, that periodically samples analog values of process and control variables directly from the controller's I/O ports.

You fairly assess that "ExperTune does all the work." You did not mention that ExperTune has advanced analysis available: power spectra and auto/cross correlation, Bode plots, and first or second order filter design.