Honeywell EN2H-0221GE51 R0808 service manual Integral action time Tn

SDC / DHC Hydraulic Components

7.3.4.10.1.2Integral action time Tn

The integral part (adjustment time) determines the dynamic behaviour of the controller and thus the time required by the controller to adjust for the actual control deviation. The adjustment time is independent of the amount of deviation.

Example:

With a sudden flow temperature control deviation of 10 K (e.g. when the system switches from reduced to daytime operation) and an I-part setting of 7 minutes, the controller will adjust for the new (10 K higher) flow temperature after the set time.

NOTE The adjustment time can be determined through the Ziegler- Nichols method. The mixed heating circuit is closed, initially, and the heat generator is taken to the maximum temperature for the heating circuit concerned. As soon as half of all consumers at the circuit to be measured have been opened, the mixer is fully opened from cold condition (room temperature) by means of the relay test function. The heat-up curve, i.e. the temperature progression over time following this action, shows an inflection point. The crossing of the tangent through that point and the time axis is the delay time. This value multiplied by the factor 3.3 is the optimum integral action time for this heating circuit.

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