6 Parameter Settings and Functions
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6.3.3.5 Offset correction/Manual reset settings [PAR2 → REST]
When selecting P / PD control mode, there are certain temperature differences even after PV
reaches stable status since heater’s rising and falling time is inconsistent due to thermal
characteristics of control objects, such as heat capacity and the heater capacity. This
temperature difference is called OFFSET. Offset can be corrected using manual reset.
Parameter Setting range
Unit
PAR2 REST 0)0 to 10)0 5)0 %
(1) Manual Reset Adjustments based on Control Results
Under stable control conditions, set the offset to 50% if PV and SV are identical, to over
50.0% if PV is lower than SV, and to below 50.0% if PV is higher than SV.
The offset correction feature can only be used when proportional control is in effect. If setting the
integral value to 0, the manual reset parameter will be displayed.
The user cannot configure the manual reset setting during heating & cooling control. Instead, the
setting is automatically set to 0% for both heating & cooling.
Applicable only when integral time is set to 0 under P control or PD control only.
Switching from heating & cooling control to standard control (P, PD control) automatically
configures the reset setting to 50%.
6.3.4 Auto-tuning
Auto tuning measures the control subject's thermal characteristics and thermal response rate,
and then determines the necessary PID time constant. (When control type [C-MD] is set as PID,
it is displayed.)
If error [OPEN] occurs during auto tuning, it stops this operation automatically.
To stop auto tuning, change the set as OFF. (It maintains P, I, D values of before auto tuning.)
6.3.4.1 Auto-tuning start/stop setting [PAR2 → AT]
Auto-tuning automatically stores PID time constants upon termination. These PID time
constants can then be modified by the user to suit their usage environment.
When auto-tuning is in progress, the AT indicator located on the front of the controller
flashes in 1 sec. intervals. When auto-tuning finishes, the AT indicator automatically goes off
and the auto-tuning parameter will return to OFF.
When auto-tuning is in progress and digital input key [DI-K] is STOP(switching
RUN/STOP) or AT(auto-tuning RUN/STOP) is set, and digital input terminal function [DI-1,
DI-2] is STOP (switching RUN/STOP) or MAN(AUTO/MANUAL control selection), auto-
tuning will be automatically ended, if concerned DI is inputted or a sensor disconnection
error occurs. (Restored the PID used prior to the auto-tuning session)
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