Pdf: Control Loop Foundation Batch And Continuous Processes

A disturbance is measured before it affects the PV. For example, measuring a change in inlet flow to a heat exchanger and pre-adjusting the steam valve. Combining feedback + feedforward is the gold standard for continuous processes.

More advanced than gain scheduling. The controller continuously re-identifies process dynamics and adjusts its own parameters in real-time. This is used for highly non-linear batch reactions (e.g., polymerization). control loop foundation batch and continuous processes pdf

Used for slow processes (e.g., reactor temperature). An inner "slave" loop (flow) responds faster than an outer "master" loop (temperature). This isolates disturbances before they propagate. A disturbance is measured before it affects the PV

Instead of modulating a valve continuously, you cycle a valve on/off. The ratio of on-time to off-time (duty cycle) determines the average energy input. Common for electric heaters in batch jacketed reactors. More advanced than gain scheduling

Tune for minimum overshoot (especially for temperature-sensitive biological batches). Derivative action is more useful here than in continuous processes because it helps anticipate the "knee" of a temperature ramp. Part 5: The Common Pitfalls (And How to Avoid Them) Regardless of whether you are in batch or continuous, the same foundational errors plague engineers. Avoid these:

The master engineer knows when to apply gain scheduling (batch) versus cascade control (continuous). But the foundation remains: