Condair Dual 2 manual.pdf

9 Appendix
9.1 Notes on humidity control
9.1.1 Notes on humidity control with the internal PI controller
The internal PI controller of the Condair Dual Hybrid Humidifier
The controller built into the Condair Dual Hybrid Humidifier is a so-called PI
controller (proportional-integral controller). The PI controller interprets the
analog signal as the actual humidity value captured by a sensor and
controls the humidification capacity via the “proportional range” and “integral
time” parameters.
– Proportional range (P-range)
The proportional range is used to smoothen the control characteristic.
The larger the selected P-range, the smoother the control characteristic
will be. However, this results in a permanent control deviation (from the
preset nominal value), proportional to the bandwidth of the P-range.
Note: Minor deviations may be compensated by optimal coordination
with the integral time parameter.
– Integral time
The integral time setting determines the period allowed to balance the
deviation of the control (due to the P-range) and to reach the nominal
value. The greater the integral time setting, the longer it takes to reach
the nominal humidity (providing better accuracy).
The smaller the integral time value, the faster the nominal humidity will
be reached (reduced control accuracy).
Controller settings
No general advice can be given on how to adjust the built-in PI controller
of the Condair Dual Hybrid Humidifier (P-range and integral time settings)
because every control distance (distance between humidifier and measuring
spot) presents a particular degree of difficulty in terms of adjustment.
However, the following rules may be used as a guideline when adjusting the
PI controller:
• Always start from the factory settings.
• In case control requires fine-tuning:
• Change values in small steps only.
• Always modify the P-range first.
• Never alter the P-Range and integral time settings simultaneously.
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