Menu (Details) - IKA RC 5 control Operating Instructions Manual

Menu (Details):

TEMPERING:
1� Control:
1) Control Mode:
Internal (int): The temperature is regulated according to
the internal temperature sensor�
Extern (ext): The temperature is regulated according to the
external temperature sensor�
2) Control parameters:
Automatic: The optimal control parameters for PID tem-
perature control are determined automatically� This is the
recommended mode�
Selecting "Automatic" allows you to set the dynamics for
temperature control�
°C
Fig. 25 (cooling curve in "Automatic" mode)
Manual: The control parameters for PID temperature con-
trol can be set manually�
"Manual" should only be used in the event of special tem-
perature control requirements�
When "Manual" is selected, the following parameters can
be set for "Internal (int)" and "External (ext)" temperature
control:
Kp: Proportional coefficient
The proportional coefficient Kp is the controller amplifica-
tion and determines how strongly the control deviation
(the difference between the target temperature and actual
temperature) directly affects the control variable (on-time
of the cooling)� Kp-values that are too large can lead to
the controller overshooting�
Ti: Integral time
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 for 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�
Td: Differential time
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 large can lead to instability of the controller�
Ts: Sampling time
The sampling time Ts (s) is the time interval over which the
control deviation is determined and the respective control
variable (dependent on Kp, Ti and Td) is calculated�
t
Ts must be adjusted to match the response characteristic
(total of all time constants) of the closed loop controlled
system, so that the control variable can deliver a uniform
and measurable change in the control deviation� Ts values
that are too small or too large can lead to instability of the
controller�
Prop_Bp: Proportional Band Maximum�
Prop_Bn: Proportional Band Minimum�
The Proportional Band is the range below (Prop_Bp) and
above (Prop_Bn) the set value in which the control output
value is calculated via the difference between the actual
and the set value and the PID parameters�
Examples of non-optimal settings:
°C
Kp too high
°C
°C
°C
Fig. 26
3) Fluids:
Under the option "Fluids", a variety of fluids can be selected�
The selected fluid limits the setting range of the target
temperature� See table in the section "Fluids (Standard in-
formation for IKA fluid)"�
The maximum and minimum temperature values of the
selected fluid can be set within these limitations�
2� Limits:
Under the option "External (ext)", the maximum and mini-
mum temperature for external temperature control can be
set�
Under "l Δ T (int - ext) l", the maximum difference be-
tween the internal and external temperature can be set�
The function limits the absolute temperature difference
between the external system and internal bath during the
heating up and cooling down process� This can protects
sensitive device like the glass reactors from thermal shock
(e�g� glass break)�
t
t
Ti too low
t
Kp too low
Ti too high
t
Td too high
18