24
Chapter 6
TUNING
6-1
Selecting the Control Method
The SDC10 is provided with three types of control method. Select the desired method
according to the
C
t
R
l
(control method) setup in parameter items.
0. ON/OFF control
1. Self-tuning
: This control method automatically changes con-
trol constants when SP is changed, or disturbance
occurs.
2. Control by PID fixed values
: Control follows fixed PID values set by auto-tun-
ing or manual operation.
6-2
Self-tuning
The controller can be self-tuned by setting the control method to self-tuning (
C
t
R
l
=
1).
Tuning is automatically started and control constants are changed by the following op-
eration or when a change in state occurs in this state.
1
Start by SP change
Start conditions:
• Initial start (*1)
SP change of
±
10%FS (*2) or more
• 2nd start onwards
SP change of
±
5%FS or more
*1 “Initial start” refers to initial tuning after the
C
t
R
l
setting is set to 1.
*2 “FS (full-scale)” refers to the width between the upper and lower temperatures set
by range code (setup item C04).
Example:
±
10%FS when the range is -200 to +400
°
C becomes:
600 (
°
C) x 10 (%) = 60 (
°
C)
2
Start by generation of deviation
Startup conditions:
• When the difference between SP and PV is sb or more
* sb: Self-tuning startup width. This is set in the parameter items.
3
Start by power ON or mode change from READY to RUN
Start conditions:
• When the power is turned ON with the difference between SP and PV at
±
sb or
more, or the mode is changed from READY to RUN
Self-tuning display
The lower right LED after the 1st digit in the upper display blinks when the self-tuning
function is ON. The LED goes out when learning ends and control constants are stored.
2
5
0
1
2
0
RDY
PV
SP
LED
