(5) A column distillate receiver has a relatively constant amplitude level oscillation (a) The amplitude of the oscillation is relatively constant for a given tuning (b) The amplitude and period of the oscillation increases as the controller gain is decreased* (c) Actual readback of level valve position indicates the minimum change in valve position routinely …
Tag Archive: controller+tuning loop+performance process+control process+dynamics valve+dynamics valve+response valve+positioners
Feb
08
Actual Control Valve Scenarios – Part 2
(1) A compressor shuts down (a) The first out sequence indicates the compressor tripped on high speed (b) A precipitous drop in suction flow followed by a rapid 1-2 second oscillation in suction flow preceded the speed deceleration from compressor shutdown (c) The readback of actual surge butterfly position indicates the valve closed before the …
Feb
01
Actual Control Valve Scenarios – Part 1
Have you seen a loop more oscillatory in automatic than in manual? Is the problem loop interaction, aggressive controller tuning, or a sticky-sloppy valve? If you have a digital positioner with position readback on a throttle valve supplied by a control valve manufacturer, you have a chance of figuring out if the valve is the …
