(4) MR (Manual reset)
With PID action “I” is automatically offset, but if “I” is OFF, it is not offset. If so, it can be offset by manually increasing/
decreasing output. This is called “manual reset.”
(5) SF (Target value function)
This function determines the strength of the overshoot preventing function when operating expert PID.
Expert PID suppresses overshoot by conducting operation for predicting and canceling the amount of overshoot by referring to
the PID value and the variation of PV value when it reached the targeted setting value (SV) (or the proportional band).
Target value function is effective only when there is an integral operation (PI, PID operation).
SF= OFF: Expert PID does not function and normal PID operates.
SF= 1.00: Minimize overshoot for expert PID contronl.
SF→ Small: Overshoot preventing function works limitedly.
SF→ Large: Overshoot preventing function works fully.
8-4. Control output
(1) Lower limit and higher limit limiter setting
Output limiter limits minimum and maximum values of control output and helps securing minimum temperature and
suppress control overshoot.
Lower limit value is given priority for output limiter setting. If minimum value is set above the higher limit value, the
higher limit value forcibly becomes the lower limit value + 1%.
Higher limit value cannot be set less than lower limit value + 1%.
(2) Proportional cycling time
The correlation between proportional cycling time and control output are as shown in the following figure.
Output 20%
Output 60%
(3) Control output characteristics
Control output characteristics can be set independently for output 1 and output 2.
For heating, set to RA (reverse action) and for cooling set to DA (direct action).
Output characteristics
Control output with 2-output characteristics is as shown in the following figure.
is heating/cooling control and
is heat + heat control.
2-output heating/cooling action output characteristics2-output heating/cooling action output characteristics
: Target set values (SV)DB (dead band)
Dead band: Shifts proportional band of control output2 for setting value.
(4) Two-position action
When conducting two-position action, frequent switching of output ON/OFF is prevented by utilizing hysteresis.
Hysteresis mode is CENT (
):
RA actionDA action
: SV value: SV value
DF: HysteresisDF: Hysteresis
Control output 1: Solid line
Control output 2: Dotted line
-DB DB=0 +DB
Controller output1
Controller output 2
100%
50%
0%
-DB DB=0 +DB
Controller output1
Controller output 2
100%
50%
0%
Out
ut ON
Out
ut OFF
Pro
ortional c
cle time
During the time equivalent to 20% when proportional
cycling time is 100%, output is ON and is OFF for the
time equivalent of the remaining 80%.
Out
ut ON
Out
ut OFF
Pro
ortional c
cle time
During the time equivalent to 60% when proportional
cycling time is 100%, output is ON and is OFF for the
time equivalent of the remaining 40%.
DF
△
Output ON
DF
△
Output ON
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