Honeywell UDC2500 ユーザーズマニュアル

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Monitoring and Operating the Controller 
104 
UDC2500 Universal Digital Controller Product Manual 
4/07 
4.11   Accutune  III 
Introduction 
Accutune III (TUNE) may be used for self-regulating and single integrating processes. 
This autotuning method is initiated on-demand, typically at initial start-up. 
There are no other requirements necessary, such as prior knowledge to the process 
dynamics or initial or post tune process line-out to setpoint or manual output. 
Also, the setpoint value is not required to change in order to initiate the tuning process, 
but the controller must be in the Automatic mode to start tuning.  The process need not be 
in a static (lined out) state and may be dynamic (changing with a steady output). 
Configuration check 
Make sure: 
• TUNE has been enabled see to Subsection 3.6 - Accutune Set Up Group for details. 
Tuning indicators 
“TUNE” will flash in the upper display until tuning is completed. 
Operation 
The “TUNE” (Accutune II) algorithm provides user-friendly, on-demand tuning in this 
controller.  No knowledge of the process is required at start-up.  The operator simply 
initiates the tuning while in the automatic mode. 
Once Accutune III has been enabled in the TUNE setup group, either “SLOW” or 
“FAST” tuning may be used.  Which one is used is selected via the lower display during 
normal operation. 
For the SLOW selection, the controller calculates conservative tuning constants with the 
objective of minimizing overshoot.  If the controller determines that the process has 
appreciable dead time, it will automatically default to use Dahlin Tuning, which produces 
very conservative tuning constants.  The SLOW selection may be useful for TPSC 
applications, as it reduces any “hunt” problems for the motor. 
For the FAST selection, the controller calculates aggressive tuning constants with the 
objective of producing quarter damped response.  Depending upon the process, this 
selection will usually result in some overshoot.  For this reason, it may be desireable to 
enable the FUZZY tune selection. See Section 4.12. When Fuzzy tune is enabled, it will 
work to suppress or eliminate any overshoot that may occur as a result of the calculated 
tuning parameters as the PV approaches the setpoint. 
The TUNE process will cycle the controller’s output two full cycles between the low and 
high output limits while allowing only a very small Process Variable change above and 
below the SP during each cycle. “TUNE” flashes in the upper display until tuning is 
completed.