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7-12
Chapter 7. PARAMETER SETUP
• Heat/cool control dead zone
The figure below shows the heat/cool output control operation:
Note (1)
On heat/cool models, this parameter sets how the relationship between heat-side
output and cool-side output should be processed with respect to the MV resulting
from PID operation.
Note (2)
Constants
oL
and
oH
functions as follows:
Note (3)
When MV is greater than or equal to 50%, the PID set on the heat side is switched
to.
When MV is less than 50%, the PID set on the cool side is switched to.
Note (4)
PID set selection is carried out by setting values or by external switch input.
Heat side PID set No.
Cool side PID set No.
PID set No.
selection
Note (4)
Note (3)
Constants
P, l, d, rE
PID operation
(reverse action fixed)
PV
SP
Heat side PID
set No. constant
oL, oH
Cool side PID
set No. constant
oL, oH
Heat-cool
output operation
Dead zone
Heat side output
Cool side output
Note (2)
Note (1)
MV
(Result of PID operation)
MV
50%
Dead
zone
Cool side
output
Heat side
output
100%
0%
Dead zone < 0
MV
50%
Cool side
output
Heat side
output
Dead zone = 0
MV
50%
Dead
zone
Cool side
output
Heat side
output
Dead zone > 0
Control output values
100%
0%
Control output values
100%
0%
Control output values
MV
100%
Cool side
output
Heat side
output
100%
0%
Cool side
oH
Heat side
oL
Heat side
oH
Cool side
oL