TOHO ELECTRONICS TTM200 - Manual (Page 92)

48-7009-E 5-22
5.4 How to set each function and description of function
5.4.1 Auto-tuning (AT) function
■ What the auto-tuning is
• Auto-tuning (AT) is a function to operate turning on and off a subject of control so that the PID
parameter best suited for a set temperature is automatically calculated and set.
• For AT, ensure to wire the input 1 terminal and output terminal (such as power supply for heater), set
the setting temperature (SV), and use the equipment in a state possible to be controlled.
• For the control type setting, select the PID control {forward operation (cooling)/reverse operation
(heating)}, heating cooling PID control and position proportional control for using them when PID
parameters are desired to be automatically set.
• Upon completion of the AT setting, the automatically set PID parameters are recorded and stored
even when the power turns off. Repeat the operation, however, in case of power-off, halted AT or
AT error during setting AT, since it causes no change of the PID parameters.
 Prohibition of the use of AT
① As AT forcibly executes turn-on and -off operations, PV greatly varies depending on a subject of control.
Do not use AT for a subject of control that cannot accept great fluctuation of PV.
② Do not use AT for a subject of control that provides fast response, such as pressure control or flow rate
control.
③ Do not use AT for a subject of control that may have a problem when a great change is applied to the
subject’s outputs, such as heater and solenoid valve.
The operating amount limiter is effective for analog outputs but not for digital outputs during AT.
The operating amount change limiter is not effective during AT.
Note Precautions on the use of AT
① The AT start screen is not displayed when the ON/OFF control is set for the control type setting.
② The AT start screen is not displayed when the self-tuning is set for the tuning type setting.
③ The time from start to completion of AT varies depending on subjects of controls.
④ Best suited PID parameters may not be obtained depending on subjects of controls.
For such cases, manually adjust the PID parameters.
⑤ AT starts also when the manual control mode is set. The mode, however, returns to the manual control
mode when AT stops. Set the control start in the control mode in order to reflect the AT result.
⑥ In case that abnormality, such as disconnected wire, is generated during AT, “ERR 02” is displayed and
AT is forcibly stopped. Repeat AT.
⑦ No change of any setting is allowed during AT.
⑧ AT may not properly complete its operation in case of subjects of controls for which temperature change
is very slow or in case of AT being executed in temperatures close to the ambience temperature due to
incorrect provision of temperature change. (“ERR 02” is displayed 3 hours after AT starts.) For such
a case, manually adjust the PID parameters.
⑨ Incompletion of AT in 3 hours may be caused by incorrect wiring of inputs and outputs, incorrect setting
of input type or incorrect setting of forward/reverse switchover. Recheck the wiring and parameters.
⑩ Best suited PID parameters may not be obtained by AT in case that the operating amount limiter is set.
The operating amount limiter is not effective during AT for digital outputs.
⑪ Best suited PID parameters may not be obtained by AT in case that the operating amount change limiter
is set.
⑫ AT for the primary control is not allowed in case that the secondary self-tuning is set for the tuning type
setting.
⑬ Parameters of the anti-reset windup are also automatically calculated in case that AT is executed for the
PID control type C.
Change the parameters to the initial values in case of changing the setting to type A or B, or not
particularly using the anti-windup.
⑭ Appropriately set the loop abnormality, since it may be caused also during AT. AT does not stop at
generation of the loop abnormality. The loop abnormality is not released even when AT stops.