Metrohm tiamo 2.3 (process analysis) - Manual (Page 1637)

￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭ 7 Instruments
tiamo 2.3 (for Process Analysis) ￭￭￭￭￭￭￭￭ 1621
7.20.8.1.5 General - PID controller
The controller acts as a PID transfer element.
Transfer function
Action diagram
Figure 1 Standard action diagram of a PID controller
The standard action diagram of a PID controller (proportional-integral-
derivative controller) in additive form has been extended to include the
two switches functioning as Boolean inputs (P in feedback and D in
feedback) so that a modified action diagram can be activated.
The control technology background is that large actuating variables arise
in connection with step responses of setpoint values through the differen-
tial component of the control algorithm which put pressure on the control
members and which can trigger vibrations in the control system. A control
algorithm whose differential component is applied only to the controlled
variable (D in feedback = ON) avoids this problem.
The following transfer functions of the closed control circuit can be imple-
mented with the inputs P in feedback and D in feedback:
P in feed-
back D in feed-
back Transfer function
off off
on off
off on