User`s manual
Table Of Contents
- 535 User's Manual
- Table of Contents
- Chapter 1: Introduction
- Chapter 2: Basic Interface
- Chapter 3: Installation
- Chapter 4: Hardware Set Up
- Chapter 5: Software Configuration
- Chapter 6: Tuning
- Chapter 7: Applications
- Control Type
- Alarms
- Duplex Control
- Slidewire Position Proportioning Control
- Velocity Position Proportioning Control
- Staged Outputs
- Retransmission
- Digital Inputs
- Remote Setpoint
- Multiple Setpoints
- Multiple Sets of PID Values
- POWERBACK
- Self Tune–POWERTUNE®
- Ramp-To-Setpoint
- Input Linearization
- Load Line
- Security
- Reset Inhibition
- Process Variable Reading Correction
- Serial Communications
- Cascade Control
- Ratio Control
- Appendix 1: Menu Flowcharts
- Appendix 2: Parts List
- Appendix 3: Troubleshooting
- Appendix 4: Calibration
- Appendix 5: Specifications
- Appendix 6: Glossary
- Appendix 7: Isolation Block Diagram
- Return Procedures and Warranty Information
- 500 Series Process Controllers User's Manual
535 User's Manual Chapter 7 89
Applications
M. SELF TUNE—POWERTUNE®
The Self Tune function of the 535 consists of two distinct components, Pretune
and Adaptive Tune. These components may be used independently or in
conjunction with one another. For best results, we recommend using them
together.
Pretune
This algorithm has three versions. Choose the type that most closely matches
the process to optimize the calculation of the PID parameters. The three Pretune
types are:
• TYPE 1 Normally used for slow thermal processes
• TYPE 2 Normally used for fast fluid or pressure processes
• TYPE 3 Normally used for level control applications
Pretune is an on-demand function. Upon initiation, there is a five second period
during which the controller monitors the activity of the process variable. Then
the control output is manipulated and the response of the process variable is
monitored. From this information, the initial Proportional Band, Reset and Rate
(P, I and D values) and dead time are calculated. When using TYPE 2 or TYPE
3 Pretune, the Noise Band (NOISE BND.) and Response Time (RESP. TIME)
will also be calculated.
In order to run this algorithm, the process must fulfill these requirements:
• The process must be stable with the output in the manual mode;
• For tuning a non-integrating process, the process must be able to reach
a stabilization point after a manual step change; and
• The process should not be subject to load changes while Pretune
operates.
If these conditions are not fulfilled, set the Adaptive Tune to run by itself.
Adaptive Tune
Adaptive Tune continuously monitors the process and natural disturbances and
makes adjustments in the tuning parameters to compensate for these changes.
In order to make accurate calculations, Adaptive Tune needs noise band and
response time values. Pretune TYPE 2 and TYPE 3 automatically calculate
these values. These values may also be entered or changed manually in the
SELF TUNE menu. For Pretune TYPE 1, Noise Band and Response Time
parameters must be entered manually.
Figure 7.12 illustrates the relationship between Pretune and Adaptive Tune
Software Configurations
Pretune by Itself
1. Go to the SELF TUNE menu (press MENU+FAST)
2. Set the TYPE parameter to PRETUNE.
3. Set the PRETUNE type to the one that best matches the process (see above
section).
4. The next parameter, TUNE PT., appears only for TYPE 1 pretune. This
parameter sets the PV point at which the output will switch off. In thermal
processes, this will help prevent overshoot. The default is AUTOMATIC.
CAUTION!
Disable Adative Tuning before altering
process conditions (e.g., for shutdown,
tank draining, etc.). Otherwise, the 535
will attempt to adapt the Tuning
parameters to the temporary process
conditions.
Adaptive Tune can be disabled via
digital input (if applicable—see Digital
Inputs in this chapter), or via menus:
1.Go to the TUNING menu.
2.Go to parameter ADAPTIVE.
Change the value to DISABLED.