J&E Hall JEHSD-0600-M-3, Техническое руководство

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Issue: 01.05.2017 Page 24
Control Logic
Parameters for neutral zone compressor control
As well as the decrease and increase differentials, 4 time parameters are preset, two for each zone,
which represent the maximum and minimum time to reach the request, equal to 0% or 100%, for the
decrease and increase respectively.
Example: the decrease/increase times (minimum and maximum) represent the time needed to change
from maximum to minimum capacity and vice-versa, and not the time between the
deactivation/activation of the individual device. For example, in the case of 4 devices with the same
capacity, an increase time of 180 s means that one device is activated every 45 s.
In the situation shown in the figure, the request sent by the controller decreases/increases slowly as
soon as the controlled value is outside of the Neutral zone, while it decreases/increases quickly the
further the controlled value moves away from the Neutral zone; in this way the response of the system
is faster when further from steady conditions.
Note: When using fixed times, the maximum and minimum must be set to the same value. In this case,
the request sent by the controller decreases/increases constantly inside the deactivation/ activation
differential.
1. Preset loading and unloading time
2. Preset time interval for loading and unloading compressor