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USER MANUAL – Release 1.2 of 01/01/2010
Page 99 of 191
Version: 02/03/2010
21.4 WORKING DESCRIPTION
While the controlled variable (defined on parameter ST09 for cooling mode and ST10 for heating mode)
remains inside the neutral zone nothing happens in terms of activation or disabling of compressors/capacity
steps.
If the controlled variables enters the “Compressors activation zone” of at least the activation offset (ST31) for
at least the ON Delay time (ST32) one compressor/capacity step is activated. More compressors/capacity
steps will be activated after the delay time CO04 if the controlled variable remains always inside the
compressors activation zone.
If the controlled variables enters the “Compressors disabling zone” of at least the disalbling offset (ST33) for
at least the OFF Delay time (ST34) one compressor/capacity step is disabled. More compressors/capacity
steps will be disabledafter the delay time CO05 if the controlled variable remains always inside the
compressors disabling zone.
22. NOTES
COMPRESSORS TEMPERATURE CONTROL
WORKING
COMPRESSORS WORKING INSIDE THE NEUTRAL OR PROPORTIONAL ZONE
A particular function is envisioned by rotation or forced insertion of compressors or steps during loads
working inside the neutral zone Par. CO (see resources management in neutral zone working mode) to
prevent prolonged working without interruption of continuity in compressors working mode.
Par. Maximum working time with temperature control in neutral zone of a step without insertion of
other resources with at least one step inserted
With at least one compressor on when the temperature control returns within the neutral zone the time set in
the par. is calculated. On the expiry of this time period the insertion of a compressor or partialisation step is
forced.
The step switch-on time is established by the "switch-on delay between steps parameter"
The solution is fixed in tens of minutes. The function is disabled if the value of the parameter is 0.
Par. Maximum working time with proportional temperature control of a step without insertion of other
resources with at least one step inserted
With just one compressor on the time set is calculated. On expiry of this, the insertion of a compressor or
partialisation step is forced in order to reach the set work set-point.
If there are no variations coming from the temperature control, every "Maximum working time with
proportional temperature control" will have forced insertion of a compressor or partialisation step.
The solution is fixed in tens of minutes. The function is disabled if the value of the parameter is 0.
Par. Maximum stay time in neutral zone without rotation of the resources
When the working returns within the neutral zone, the time set in the par. is calculated. On expiry of this time,
the compressor engaged is switched-off and the insertion of another compressor is forced on the basis of
rotation.
The solution is fixed in hours. The function is disabled if the value of the parameter is 0.
23. DYNAMIC SET-POINT FUNCTION
The regulator allows to modify the set-point by adding a proportional value to the 4-20 mA analogue input or
depending on the temperature of the external air measured by the probe. There are two purposes to this
function: save energy or make the unit function with particularly critical external temperatures. For this
reason, both in cooling and in heating mode, it is possible to add or subtract a determined proportional value
from parameters Sd01 / Sd02 to the set-point or of the input or external temperature.
The regulator is active if
•
the activation parameter Sd01 is different to 0 in cooling working mode
•
the activation parameter Sd02 is different to 0 in heating working mode
•
a 4÷20 ma probe is configured as input dynamic set-point or an NTC probe is configured as an external
air probe
