Pid Tuning Guide - Zener 8000 Application Manual

Application SW08020: Pump PID 2 [Advanced Pump PID Control]

PID Tuning Guide

The Proportional gain:
Prop. Band value is the proportion of input required to generate 100% at the output of the PID control. For
example H01 Prop. Band is 300.0%, the proportional gain is 100/300 = 0.333. That is 3 units of input will
generate 1 unit of output. The higher the % value, the lower the 'proportional gain'.
The integral time: The integral action adds a corrective component to reduce a constant error difference
between set point and feedback signals. The greater the error, the quicker the gain increases. The H02 Integ.
time value sets the time to 'repeat' the error difference between set point and feedback signals - This assumes
the Proportional gain is equal to 1.
A low H02 Integ. time value attempts to regulate the process variable quickly. However if excessively low, over
shooting and under shooting will be more prominent.
A high H02 Integ. time value diminishes over shooting and under shooting. However regulation takes longer to
achieve.
Guide to PID Tuning:
Step Problem
1. The plumbing is set for typical flow but the
system responds too slowly
2. The system starts to overshoot or oscillate
3. The system still responds slowly
(after adjusting H01 Proportional band )
4. The system starts to overshoot or oscillate
(after adjusting H01 Proportional band )
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amplifies the difference between the set point reference and feedback signals. The H01
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Action
1.1 Stop the ZENER 8000 & pump
1.2 Halve the value of H01 Proportional band (avoid adjustments below
10%)
1.3 Stop & restart the ZENER 8000 & pump.
1.4 Observe the time it takes to reach pressure (or reacts to changes)
1.5 Repeat if the response is slow. Keep halving H01 Proportional band
until overshoots or starts to oscillate then proceed to step 2.
2.1 Stop the ZENER 8000
2.2 Double the value H01 Proportional band
2.3 Observe the time it takes to reach pressure (or reacts to changes)
2.4 Repeat if the system still overshoots or oscillates proceed to step 3.
3.1 Halve the H02 Integral Time
3.2 Observe the time it takes to reach the pressure (or reacts to changes)
3.3 Repeat if the response is still slow (half Again) otherwise proceed to
step 4."
4.1 Double the H02 Integral Time
4.2 Observe the time it takes to reach the pressure (or reacts to changes)
4.3 Repeat if the system still overshoots or oscillates (half Again)