Selecting The Control Method; Cooling Coefficient; Heating And Cooling Control; Manual Operation - Omron E5AK User Manual

CHAPTER 4 APPLIED OPERATION

4.1 Selecting the Control Method

J Heating and
cooling control
F Dead band
Output
Heating
side
0
Set point
F Cooling coeffi-
cient
F Manipulated vari-
able at stop
Switching with

Manual operation

4--2
When selecting the control method, set the parameters according to the
following table. (Parameters are factory-set to heating control.)
Parameter
Control output 1
Control
Method
Heating control
Control output (heat)
(Standard)
Cooling control
Control output (heat)
(Standard)
Heating and cooling
Control output (heat)
control
For details on how to assign outputs, see 3.3 Setting Output Specifica-
tions (page 3-6).
• When heating and cooling control is selected, the "deadband" and
"cooling coefficient" parameters can be used.
The dead band is set with the set point as its center. The dead band
width is the set value of the "dead band" parameter (level 1 mode). Set-
ting a positive value produces a dead band, while setting a negative
value produces an overlap band.
Dead band: dead
band width = positive
Cooling
side
PV
If the heating and cooling characteristics of the control target greatly
differ, preventing satisfactory control characteristics from being
obtained by the same PID parameters, adjust the proportional band (P
at cooling side) using the cooling coefficient to balance control between
the heating and cooling sides. In heating and cooling control, P at the
heating or cooling side is calculated by the following formula:
Heating side P = P; Cooling side P = cooling coefficient ¢ P
• In heating and cooling control, the manipulated variable output that
is output when controller operation is stopped is dependent on the set
value of the "MV at stop" parameter (level 2 mode) in the same way as
for standard control.
• However, note that in heating and cooling control, the manipulated
variable at the cooling side is treated as a negative value for the sake
of convenience. When the manipulated variable at STOP is a negative
value, the manipulated variable is output to only the cooling side, and
when a positive value, the manipulated variable is output to only the
heating side. The factory setting is "0". If the controller is operated
using the factory setting, the manipulated variable is not output to
both the heating and cooling sides.
When the overlap band is set, the bumpless function that operates when switch-
ing between manual and automatic operation may not work.
Control output 2
assignment assignment
-
-
Control output (cool)
Output
Heating
side
0
Set point
Direct/Reverse
operations
Reverse operation
Direct operation
Reverse operation
Overlap band: dead
band width = negative
Cooling
side
PV