7. FUNCTIONS
IMSRM02-E6
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(6) Enhanced autotuning
The enhanced autotuning function is used to automatically measure, calculate and set the optimum
PID constants centering around the temperature set value. This function can start from any state after
power on, during a rise in temperature or in stable control. In addition, the
AT bias
can be set.
z
z
z
z
AT bias
The AT bias is set when the autotuning function in which the measured value (PV) does not exceed
the set value (SV) is activated. Our autotuning method performs ON/OFF control centering around the
set value (SV), then calculates and sets each of the PID constants by hunting the measured value (PV).
However, overshooting caused by this hunting may not be preferable depending on the controlled
object. In such a case, the desired AT bias is set.
If it is set, another set value (SV) to activate the autotuning function [AT point] can be set.
When AT bias is set to the minus (-) side
Measured value (PV)
Set value (SV)
AT point
AT bias
Time
(7) Direct/reverse action
No selection can be made for heat/cool control.
•
Direct action: The manipulated output value (MV) increases as the measured value (PV) increases.
This action is used generally for cool control.
•
Reverse action:The manipulated output value (MV) decreases as the measured value (PV)
increases.
This action is used generally for heat control.
(8) Auto/manual transfer
By this function the manipulated output value (MV), can be changed over between the output amount
calculated against the set value (SV) [Auto mode] and the manually set output amount [Manual
mode].
