Accutune Set Up Group - Honeywell UDC3500 Product Manual

Configuration

3.7 Accutune Set Up Group

Introduction
Accutune III automatically calculates GAIN, RATE, and RESET TIME (PID) tuning
constants for your control loop. When initiated on demand, the Accutune algorithm
measures a process step response and automatically generates the PID tuning constants
needed for no overshoot on your process.
The Accutune III set up group offers these selections:
Fuzzy, Fuzzy Overshoot Suppression: When enabled, this configuration will suppress
or eliminate any overshoot that may occur as a result of the existing tuning
parameters, as the PV approaches the setpoint.
Tune, Demand Tuning: This tuning cycles the output to the output limits causing the
PV to oscillate around the SP value. This tuning does not require the process to be at
lineout (stabilized) and may be moving. The tuning process is initiated through the
operator interface keys or via a digital input (if configured). The algorithm then
calculates new tuning parameters and enters them in the tuning group. Tune will
operate with PIDA, PIDB, PD+MR and Three Position Step Control algorithms.
SP, SP Tuning: When activated in automatic control, the output makes an output step
in the direction of the SP and starts measurement activities to calculate the tuning
parameters based on the PV response. In order to work properly, this tuning requires
that the process be at lineout (stabilized) for a period before SP Tune is initiated.
SP tuning continuously adjusts the PID parameters in response to setpoint changes.
You can select tuning on minimum setpoint changes of 5 % up to 15 % span.
Perform SP tuning after you have configured the controller. SP Tuning does not
operate with the Three Position Step Control algorithm.
Tune + PV or SP + PV, PV Tuning: The (TUNE) Demand Tuning or the (SP) Setpoint
Tuning portions of these selections work as stated above. PV Adapt will occur during
Process Variable (PV) disturbances (0.3% span or larger) which result from non-
linearities, process dynamics, load changes, or other operating conditions. When this
condition exists, the controller monitors the process response for 1 and 1/2 process
cycles around the setpoint to determine whether there has been a true process change
or a momentary upset.
Process retuning occurs as the process dynamics are learned. When the process is
being learned with possible retune, a "t" is shown in the upper left display digit.
Simplex Tuning is used when a Simplex Control Algorithm is configured and uses the
current SP value and alters the output over the Output Limit Range.
Duplex Tuning is used when a Duplex Control Algorithm is configured. To perform a
Duplex Tune, Two Local Setpoints must be configured per the Control Group in
Section 3.17.
See Section 4.10 for additional information.
62 UDC3500 Universal Digital Controller Product Manual 10/05