Tag Archive: control+valve+dynamics limit+cycles process+dynamics PID+performance

Dec
11

Getting a Kick Out of Stick-Slip Compensation

Last week, we discussed the deadly and sticky situations of some control valves. I once thought a variable speed drive (VSD) was the solution until Bob Heider pointed out that some VSD packages may not be as sensitive as a well designed throttling control valve. A VSD resolution may be 0.4% whereas a sliding stem …

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Dec
04

Deadly Deadband

A control valve isn’t doing much to help a control loop deal with the minute by minute onslaught of disturbances if it does not respond to the controller’s output. Yet there is normally nothing in a control valve’s specification form to insure the control valve actually moves. A step forward has been the ANSI/ISA standard …

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