Nor-Cal SDC15 Controller - Manual (Page 68)

■ AT (Auto-tuning)
The following AT related items can be set:
• When the control method is other than the ON/OFF control (CtrL ≠ 0), the
display and setting can be made.
• The MV (manipulated variable) during execution of AT can be limited by the
MV low limit at AT (At.oL) and MV high limit at AT (AT.oH).
When the Heat/Cool control is not used, the MV becomes a value limited by both
the MV low limit at AT (At.oL)/MV high limit at AT (At.oH) and MV low limit
(oL-1)/MV high limit (oH-1) of the PID constant.
When the Heat/Cool control is used, the MV becomes a value limited by the MV
low limit at AT (At.oL)/MV high limit at AT (At.oH), the heat MV becomes a
value limited by the MV low limit (oL-1)/MV high limit (oH-1) of the PID
constant, and the cool MV becomes a value limited by the output low limit
(Cool) (oL1.C)/output high limit (Cool) (oH1.C) of the PID constant.
• The AT type (At.ty) is a setting item that the PID constant of the control
characteristics suitable for the system is calculated by the AT.
Set value 1 (immediate response) is adjusted to the process that the heater
heating directly affects the PV to aim at the adjustment considering the
immediate response.
Set value 2 (stability) is adjusted to the process that the heater heating indirectly
affects the PV to aim at the adjustment considering the stability.
When compared to the AT functions of Yamatake's conventional models, set
value 1 (immediate response) is close to the
SDC10 and set value 0 (normal) is
close to the SDC20/21 .
5-18
Chapter 5. DETAILED DESCRIPTION OF EACH FUNCTION
Item (Setting display/bank) Display Contents Initial value User level
MV low limit at AT
(Parameter
setup/Parameter bank) -10.0 to +110.0% 0.0% Simple,
Standard,
High function
MV high limit at AT
(Parameter
setup/Parameter bank) -10.0 to +110.0% 100.0%
AT type
(Parameter setup/Extended
tuning bank) 0: Normal (Standard control characteristics)
1: Immediate response (Control
characteristics that respond immediately to
external disturbance.)
2: Stable (Control characteristics having less
up/down fluctuation of PV)
1
AT Proportional band
adjust
(Parameter setup/Extended
tuning bank) 0.00 to 99.99 1.00 High function
AT Integral time adjust
(Parameter setup/Extended
tuning bank) 0.00 to 99.99 1.00
AT Derivative time adjust
(Parameter setup/Extended
tuning bank) 0.00 to 99.99 1.00