Improve Process Dynamics with Powerful
"What If…" Tools
The Loop Simulator is a software package that simulates complex control loop dynamics for
single loop, cascade, and feedforward systems. It can be used as a stand-alone simulator
or used in combination with our Advanced PID
Optimizer. Loop Simulator supports over 400 different
industrial PID controllers and other advanced control
algorithms.
Loop Simulator supports your control loop inquiries by enabling easy comparison of control
schemes and tuning via simultaneous side by side plotting. Thus you can test control
schemes for robustness and stability before you download them. And you can train offline
without risk to your process.
Simulates industrial:
Try different tuning for the same process. Screen
shows response using the four sets of tuning categories
automatically calculated by the Loop Simulator using one of over 400
controllers available.
Simulate industrial control loops with any combination of:
- Over 400 industrial
controllers
- Customize your own PID controller
- Model predictive controller (Dahlin, IMC or Vogel-Edgar)
- Smith Predictor (up to second order with lead)
- Output limits and saturation
- PV filter (shows true PV and filtered)
- Hysteresis
- Measurement and valve noise
- Digital sampling effects
- Gain
- Dead Time
- Any number of integrators
- 2 lead times
- Over 20 lags
- Inverse response
- Overdamped, underdamped
Response Plots for Single Loop
Time response plots
- Closed Loop (Automatic)
- Setpoint Step
- Setpoint Pulse
- Setpoint Ramp
- Load Step
- Load and Setpoint Step
- Open Loop (Manual)
- Controller Output Step
- Controller Output Pulse
- Controller Output Ramp
Frequency Plots
- Process Only
- Controller Only
- Controller With Process
- Controller With Inverse Process
- Combined Open Loop (to PV)
- Closed Loop to Setpoint
- Closed Loop to Load
Robustness Plot
Unique to ExperTune, robustness plots show the trade-off between fast response and
sensitivity to the process changing.
Cascade
Cascade control can very often improve control loop performance by a factor of 3 to 10.
Loop Simulator helps you tune and analyze cascade control loops. From the model of the
process, obtained from PID Tuner/Analyzer, Loop Simulator provides optimal tuning for:
- Inner controller
- Outer controller (inner controller connected—dependent on inner controller tuning)
- Outer controller (inner controller bypassed)
Should you use cascade control? See the benefit of using cascade control - view responses
with and without the inner controller present.
Response plots for Cascade
- Closed Loop (Automatic)
- Outer Controller Setpoint Step
- Outer Controller Setpoint Pulse
- Outer Controller Setpoint Ramp
- Load Step Before Inner Process
- Load Step Before Outer Process
- Outer Open, Inner Closed
- Inner Controller Setpoint Step
- Inner Controller Setpoint Pulse
- Inner Controller Setpoint Ramp
- Load Step Before Inner Process
- Open Loop (Manual)
- Inner Controller Output Step
- Inner Controller Output Pulse
- Inner Controller Output Ramp
- Advanced - Bypass Inner Controller
- Setpoint Step
- Setpoint Pulse
- Setpoint Ramp
- Load Before Inner Process
- Load Before Outer Process
Frequency plots for Cascade
- Outer Loop
- Process Only
- Controller Only
- Controller With Process
- Controller With Inverse Process
- Combined Open Loop (to PV)
- Closed Loop to Load (after Outer Controller)
- Closed Loop to Load (before Outer Process)
- Inner Loop
- Process Only
- Controller Only
- Controller With Process
- Controller With Inverse Process
- Combined Open Loop (to PV)
- Closed Loop to Setpoint
- Closed Loop to Load
- Advanced - Bypass Inner Controller
- Process Only
- Controller Only
- Controller With Process
- Controller With Inverse Process
- Combined Open Loop (to PV)
- Closed Loop to Setpoint
- Closed Loop to Load
Robustness plots for Cascade
- Outer Loop
- Inner Loop
- Advanced - Bypass Loop
Feedforward
Loop Simulator calculates, and simulates responses using feedforward compensation.
Feedforward control can have a return on investment that can be directly proportional to
the improved recovery from upsets. The closer the feedforward system can keep the loop at
setpoint, the closer you can run to a constraint, quality variable, or key ingredient
addition.
For example, with addition of a key ingredient you may want to add just enough, but not
more, to reach specification. Better control to setpoint lets you get closer to
specification saving on the key ingredient. In another example, reactor yield may be
higher closer to a temperature limit. Past the limit, the reaction goes unstable, but the
closer to the limit, the higher the yield. The better control, the closer you can operate
near the limit. Feedforward may help in both of these examples to maintain the process
variable at the setpoint.
Working in conjunction with ExperTune's PID Tuner/Analyzer, Loop Simulator finds the best
feedforward compensator to use. From process, data PID Tuner/Analyzer identifies the
feedback and feedforward models. Enter the models into Loop Simulator and click the
"Suggest Values" button on the compensator page. Simulation quickly compares response
with and without the feedforward compensator. In practice, ExperTune
recommends to start with the compensator gain and lead reduced by a factor of 2.
Response Plots for Feedforward
- Closed Loop (Automatic)
- Setpoint Step
- Setpoint Pulse
- Setpoint Ramp
- Load Step
- Load and Setpoint Step
- Open Loop (Manual)
- Controller Output Step
- Controller Output Pulse
- Controller Output Ramp
Frequency Plots for Feedforward
- Process Only
- Load Process Only
- Compensator Only
- Controller Only
- Controller With Process
- Controller With Inverse Process
- Combined Open Loop (to PV)
- Closed Loop to Setpoint
- Closed Loop to Load
- Compensator and Process With Load Process
Robustness Plot for Feedforward
Unique to ExperTune, robustness plots show the trade-off between fast response and
sensitivity to the process changing.
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