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(4) 1-62 AT execution point setting screen
For the purpose of avoiding hunting due to a limit cycle with a
set SV AT execution, a virtual SV value (AT execution point)
is set for AT to run at a point away from the actual SV value.
Note 1: For AT execution point, an absolute value of difference
between SV value and virtual SV value is to be input.
Note 2: When 0 is set for AT execution point, SV value serves as
the AT point.
Note 3: When PV value is in the AT execution point area, SV value
serves as the AT point.
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When AT is executed, PID constants are calculated and defined
from repeated ON/OFF action (100%/0%) output for the
measuring value increase and decrease around the set value and
are stored in the internal memory to complete operation. Upon
completion, control using stored PID constants begins.
How to execute AT
1. Press the
key in the mode 0 screen group. Auto tuning is
brought to the state of standby. (AT lamp lights.)
2. Press the
key to register. Auto tuning is executed. (AT lamp
flashes.)
Note: AT can be executed even with remote SV. (The remote SV
at the time when AT execution point is set is used in the
execution.)
Note: AT cannot be executed in the mode 1 screen group.
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AT is not executed in the following conditions (When the
key
is pressed, the AT lamp goes out.)
1. During ramp control
2. During manual operation
3. In the state of STBY
4.
“
oFF
”
setting for proportional band (ON/OFF action)
5. Selection of 2 or 3 on the keylock mode setting screen
6. Scaleover of PV value (measured value)
Cancellation of AT
AT can be cancelled in mid-operation by pressing the
key
again. Press the
key for confirmation. The AT lamp goes out.
Note: When AT is cancelled in the mid-operation, PID values
remain unchanged.
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AT is automatically cancelled under the following conditions:
1. Output value remains at 0% or 100% for two or more hours.
2. Power supply is interrupted due to power failure or for other
reason.
3. Scaleover of PV (measured value) during AT execution.
4. STBY is executed.
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On the 0-1 OUT1 control output value display screen and 0-2
OUT2 control output value display screen, it is possible to change
to the control output manual mode and to set a manual control
output value.
Change to manual control mode
On a display screen of control output intended to be changed (0-1
or 0-2), press the ENT key for 3 seconds continuously. The
MAN lamp flashes and it is changed to the manual mode to allow
you to set a control output value by means of the
or
key.
Likewise, the manual control output mode is switched to the
ordinary automatic mode by continuously switching the
key
for 3 seconds. Then the MAN lamp goes out.
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Rules applied to manual control
1. Manual control action and output value are kept in memory
even when power is turned OFF and is reapplied.
2. When the measuring range is changed, the manual control mode
is cancelled and replaced by automatic control mode.
3. Upon switching auto to manual, balanceless and bumpless
control is carried out. If the measured value is out of the
proportional band at the time of mode switching, however,
balanceless and bumpless control is not performed.
4. The control output range in the manual control mode is within a
range defined by output limiter. (When P=OFF or during
ON/OFF action, control is carried out with lower limit
: %
and higher limit
100.0%.
Nevertheless, 100% output is displayed as follows on account of
limited display space.
