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Executing Heating and Cooling Control Section 4-4
4-4 Executing Heating and Cooling Control
4-4-1 Heating and Cooling Control
Heating and cooling control operates when a cooling control output has been
allocated to one of the outputs. For example, to set heating and cooling con-
trol for ch1, allocate “cooling control output for ch1” to one of the outputs.
• When heating and cooling control is selected, the “dead band” and “cool-
ing coefficient” parameters can be used.
• Refer to 3-4 Setting Output Specifications for allocation methods for heat-
ing and cooling control.
• The default allocation is “heating control output.”
Dead Band The dead band is set with the SP as its center. The dead band width is set in
the “dead band” parameter in the adjustment level. Setting a negative value
produces an overlap band.
Default is “0.0 EU.”
Cooling Coefficient If the heating and cooling characteristics of the control target differ enough to
prevent satisfactory control characteristics from being obtained using the
same PID constants, control between the heating and cooling sides can be
balanced by adjusting the proportional band (P) at the cooling side control
output using the cooling coefficient. In heating and cooling control, P at the
heating or cooling control output sides is calculated using the following for-
mula: Heating side P = P
Cooling side P = Heating side P
× Cooling coefficient
The cooling coefficient is applied to heating side P to obtain cooling side out-
put control whose characteristics (i.e., the cooling side P) differ from those on
the heating side control output.
Output Output
Heating
side
Heating
side
Cooling
side
Cooling
side
00
PV PV
SP SP
Dead band:
Dead band width = positive
Overlap band:
Dead band width = negative
Output
PV
0
Cooling side
P
Heating side
P
Heating side P × 1.5
SP
Output
0
PV
SP
Cooling side P
Output
Heating side
P
Heating Side P
× 0.8
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