Honeywell EN2H-0221GE51 R0808 service manual Modulation of P part Xp, Modulation of sample time Ta

SDC / DHC Hydraulic Components

Activation of The modulating burner stage is activated when the heat generator modulation temperature has dropped below the set nominal temperature by

more than 1 K. The burner is enabled through the burner relay. As soon as the heat generator temperature crosses the switch-off level the burner is deactivated, in contrast to the mixed heating circuit parameters.

Adjustment Adjustment to the setpoint temperature is realised through the conventional 2-point output (activating the burner) and an additional 3-point output for modulating the actuator in the burner. The temperature is registered by the heat generator sensor. In contrast to mixed heating circuit control, no end position function is assigned to this actuator. The control algorithm is running continuously.

Minimum burner run The burner remains in operation for the duration of the set time minimum burner runtime irregardless of temperature-based

switch-off conditions.

Minimum and If the heat generator maximum temperature is exceeded or the maximum heat generator minimum temperature is undershot, the same

temperature limit functions apply as with conventional heat generators.

7.1.9Modulation of P part (Xp)

Function The proportional part Xp defines how a step change of the setpoint effects a change of the corresponding actuator according to the new setpoint.

Example:

With a max. heat generator temperature of 70°C, the actuator in the modulating burner must cover a temperature differential of 50 K (starting from a room temperature of 20°C). This corresponds to a control deviation of 100%. The set value is calculated as follows:

Xp (%)/K x 50 K = 100% or Xp = 2%/K

7.1.10Modulation of sample time Ta

The sample time is a controller-internal quantity which defines the time interval between two subsequent actuator pulses in the presence of a control deviation. Shorter sample times allow finer adjustments.

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