13
•
Temperature control type (AUTO) (heating):
AUTO 1:
AUTO 1 is the default setting� The default PID settings are
used automatically�
Heating up curve in AUTO 1 control (AUTO 1):
Fig. 15
Proportional coefficient of PID (
Kp 1
)
Integral time of PID (
Ti 1
)
Differential time of PID (
Td 1
)
Fig. 14
The proportional coefficient
Kp
is the controller ampli-
fication and determines how strongly the control devia-
tion (the difference between the target temperature and
actual temperature) directly affects the control variable
(cooling down time)�
Kp
values that are too large can
lead to the controller overshooting�
The integral time
Ti (s)
is the correction time and deter-
mines how strongly the duration of the control deviation
affects the control variable�
Ti
compensates an existing
control deviation� A high
Ti
means a smaller and slower
effect on the control variable�
Ti
values that are too small
can lead to instability of the controller�
The differential time
Td (s)
is the derivative time and de-
termines how strongly the rate of change of the control
deviation affects the control variable�
Td
compensates for
rapid control deviations� A high
Td
means a smaller and
slower effect on the control variable�
Td
values that are
too small can lead to instability of the controller�
AUTO 0:
For special requirements, AUTO 0 can be used with man-
ual adjustment of the control parameters�
If the PID control (AUTO 0) option is selected, the follow-
ing items including
Kp 1
,
Ti 1
and
Td 1
could be set�
Otherwise they are not displayed in the menu list�
Note:
Inappropriate settings may produce the following
heating up curves:
•
Alarm and button tone (BEEP):
BEEP 0:
no alarm and button tone
BEEP 1:
alarm and button tone is activated
•
Calibration and adjustment (CALI):
CALI 0:
Reset calibration
CALI 2:
2-point calibration
CALI 3:
3-point calibration
°C
t
°C
t
Kp too high
°C
t
Ti too low
°C
t
Td too high
°C
t
Kp too low
Ti too high
