Overlap/Dead Band Function - Mitsubishi Electric MELSEC iQ-F FX5 User Manual

4.10

Overlap/dead Band Function

In the heating-cooling control, the temperature process value (PV) significantly changes due to a slight heating or cooling
control output when the heat produced by a controlled object and natural cooling are being balanced. Consequently, an
excessive output may be implemented.
The temperature where the cooling control output starts can be shifted using this function; consequently, whether control
stability is prioritized or energy saving is prioritized can be selected.
Overlap
The overlap refers to the temperature area where both of heating control and cooling control are implemented. In the
temperature area where both heating and cooling output overlap, both of the outputs negate each other, and so the control
gain becomes moderate. Consequently, the variation amount in the temperature process value (PV) for the output becomes
small, improving control stability.
If establishing an overlap area, set a negative value in the "Overlap/dead band setting".
Manipulated value
(MV)
100%
Heating output value
0%
Dead band
The dead band refers to the temperature area where neither heating control output nor cooling control output is implemented.
When the temperature process value (PV) is stable within this area, output is not implemented for a slight change in the
temperature, resulting in energy saving.
If establishing a dead band area, set a positive value in the "Overlap/dead band setting".
Manipulated value
(MV)
100%
Heating output value
0%
Setting method
Configure the settings as described below.
[Navigation window]  [Parameter]  Target module  [Module Parameter]  [Application Setting]  [Heating/cooling
control setting]  [Overlap/dead band setting]
4 FUNCTION
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4.10 Overlap/dead Band Function
Cooling proportional band
(Pc)
Heating
proportional band
(Ph)
Cooling output value
Set value (SV)
Overlap
Heating
proportional
band
(Ph)
Set value (SV)
Dead
Band
Process value (PV)
Cooling
proportional
band
(Pc)
Cooling output value
Process value (PV)