ExperTune has released a new software wizard to help process engineers optimize the control strategy of level control loops in all types of process vessels. The wizard uses the design experience of Greg Shinskey.Level loops present a unique challenge to process control since the control objective varies widely, from tight level control in reactors to averaging level control in surge tanks.Whatever the performance requirement, whether it be a complex application like a hot vapor by-pass, or a simple surge tank, the new ExperTune Level Wizard guides engineers through choosing and implementing the best level loop control strategy for each individual need. The wizard: 1.
Identifies the goals for the level loop 2. Chooses the level control strategy that matches the plant's goals 3. Finds the best P, PI, or PID parameters to meet those goals 4.
Provides built-in user guidance (see figure below).The wizard pays for itself quickly by: · Forcing the controls to adhere to the operational objectives, maximizing profits · Maximizing surge usage for smoother response to upsets, keeping critical quality variables on target · Savings in cost, better quality, safer operations, increased throughput, and more consistent quality.ExperTune Level Wizard optimizes level loops with the following level control goals:
- Fast and accurate control of level to setpoint, with and without derivative control action.
- Averaging level, where the purpose of the tank is a surge vessel to smooth flow upsets.
The result is the fastest possible recovery back to setpoint in the face of upsets.
In this case, the vessel is used to reduce the effects of upstream disturbances.
The goal is that one unit feeding a second should disturb the second as little as possible.
--Averaging level with P action only - level is floating, maximizing the use of the surge vessel to smooth flow upsets.
--Averaging level with P and I action - level floats and slowly returns to setpoint.
Averaging level techniques may use tank volume.
Using simple test data, the ExperTune Level Control Wizard automatically determines tank volume and controller settings.ExperTune Inc.Lake Country Research Center1020 James Drive, Suite AHartland, WI 53029-8305voice: (262) 369-7711FAX: (262) 369-7722Website: www.expertune.com
