Honeywell EXCEL 5000 User Manual page 188

ALPHABETIC REFERENCE
74-5577–33 (US)
EN2B-0184 GE51 R0518 (Europe)
The following figure illustrates this relationship.
Parameter P10 (optimum stop factor) weights the influence of the control difference
on the characteristic curve. If Parameter P10 is zero, EOV calculates early
shutdown based on OAT only.
Adaptation of Factors
For the advance calculation of the switch-on point in heating/cooling operation, EOV
uses a model of controlled operation. In the heating mode, Parameter P4 (high-
speed preheat factor) defines this model. The factor indicates how much time is
required to overcome a control difference of 1K. In the cooling mode, Parameter P8
(high-speed cooling factor) defines this model.
The two modes require different curves because cool-down and heat-up occur at
different rates. For example, in a factory, the factor for rapid cool-down is always
larger than the factor for rapid heat-up because cooling down by 1K takes longer
than heating up by the same amount. This effect is because the heat from machines
supports heating up, while it works against cooling down.
EOV can adapt both factors automatically to the actual circumstances. This
adaptation occurs when you select New start or Enable for the Factor Adaption field
in the internal parameters dialog box. EOV adapts the factors with decreasing
weighting, that is, the new factors calculated after the first optimization may change
P4/P8 significantly, the factors calculated after the second optimization somewhat
less, and so on. After the first successful optimization, EOV sets Parameter P11 to
zero. This setting corresponds to Adaption enable. You can prevent or interrupt
adaptation by setting the Adaption button to disable (P11 = 1).
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EXCEL CARE CONTROL ICONS