| Operating
Unit / Process |
What
to Control |
Why
Is It Difficult |
Which
MFA to Use |
Evaporators
Application
Sheet
Article |
Density |
Interacts with level |
MIMO MFA or FB/FF MFA |
| Level |
Interacts with density |
MIMO MFA or FB/FF MFA |
Ovens and Dryers
Request
white paper |
Outlet temperature |
Large time delays |
Anti-delay MFA |
| Zone temperature |
Multiple zones |
MIMO MFA |
| Combustion |
Optimal fuel-air-ratio |
SISO MFA |
Extruders
Request
white paper |
Density or moisture |
Large time delays |
Anti-delay MFA |
| Temperature |
Time-varying |
SISO MFA |
| Pressure |
Nonlinear |
SISO MFA |
Wastewater treatment
Application
Sheet
|
pH Control |
Large gain changes in Log scale, large delay time |
MFA pH or Anti-delay MFA pH |
| Food acid concentration |
pH Control |
High accuracy pH control |
MFA pH or Anti-delay MFA pH |
Tomato hotbreaks
Application
Sheet
|
Temperature |
Large feed variations |
SISO MFA |
| Sterilization / steam injection |
Temperature |
Large load changes |
SISO MFA |
| Food products |
Quality variables (Density, moisture, surface temp,
etc.) |
Large time delays |
Anti-delay MFA |
Heat-exchangers
Request
white paper |
Temperature |
Interactions among temperature points |
MIMO MFA or FD/FF MFA |
Cooling towers
Request
white paper |
Levels and flows |
Multivariable |
MIMO MFA or Balanced MFA |
| Cooling tunnels |
Surface temperature |
Large time delays |
Anti-delay MFA |
| Zone temperature |
Multiple zones |
MIMO MFA |
Steam boilers
Application
Sheet |
Steam temp and pressure |
Large load changes |
Robust MFA |
| Steam drum level |
Inverse-action |
3-Element Anti-delay + FF MFA |
| Combustion |
Optimal fuel-air-ratio |
SISO MFA |
