Table of Contents
Appendix F
PID Function Blocks
Troubleshooting an
Autotune Process
PID Application Example
326
You can tell what is going on behind the autotune process from the sequences of
control output. Here are some known sequences of control output and what it
means if autotune fails. For the ease of illustrating the sequence of control output,
we define:
Load: 50
Step: 20
Output Sequence 1: 50 -> 70 -> 30
Sequence Condition
Process value reached 'first peak' and
'second' peak in time
Output Sequence 2: 50 -> 70 -> 50
Sequence Condition
Process value not able to reach
'first peak'
Output Sequence 3: 50 -> 70 -> 30 -> 50
Sequence Condition
Process value not able to reach
second peak
Output Sequence 4: 50 -> 70
Sequence Condition
Process value not able to reach First
peak in time
Water In
Water Level
The illustration above shows a basic water level control system, to maintain a
preset water level in the tank. A solenoid valve is used to control incoming water,
filling the tank at a preset rate. Similarly, outflowing water is controlled at a
measureable rate.
Autotune Result
Action for Autotune Fail
Likely successful
NA
Autotune Result
Action for Autotune Fail
Likely unsuccessful
Reduce Deviation or Increase Step
Autotune Result
Action for Autotune Fail
Likely unsuccessful
Increase Deviation or increase Step
Autotune Result
Action for Autotune Fail
Likely unsuccessful
Increase ATDynamSet
Tank
Rockwell Automation Publication 2080-UM002K-EN-E - March 2019
Water Out
- Quick Links:
- Micro830 Controllers
- Micro850 Controllers
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