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ifm
Programming Manual
ecomatmobile
CabinetController (CR0301) Runtime System V05
2016-04-21
ifm function elements
ifm function elements for the device CR0301
>
PID2
9167
Unit type = function block (FB)
Unit is contained in the library
ifm_CR0301_Vxxyyzz.LIB
Symbol in CODESYS:
>
Description
347
PID2 handles a PID controller with self optimisation.
The change of the manipulated variable of a PID controller has a
p
roportional,
i
ntegral and
d
ifferential
component. The manipulated variable changes first by an amount which depends on the rate of
change of the input value (D component). After the end of the derivative action time TV the
manipulated variable returns to the value corresponding to the proportional component and changes in
accordance with the reset time TN.
The values entered at the inputs KP and KD are internally divided by 10. So, a finer grading can be
obtained (e.g.: KP = 17, which corresponds to 1.7).
NOTE
The manipulated variable Y is already standardised to the PWM FB (RELOAD value = 65,535). Note
the reverse logic:
65,535 = minimum value
0 = maximum value.
Note that the input value KD depends on the cycle time. To obtain stable, repeatable control
characteristics, the FB should be called in a time-controlled manner.
If X > XS, the manipulated variable is increased.
If X < XS, the manipulated variable is reduced.
A reference variable is internally added to the manipulated variable.
Y = Y + 65,536 – (XS / XMAX * 65,536).
The manipulated variable Y has the following time characteristics.
Figure: Typical step response of a PID controller
Summary of Contents for Ecomat 100 Mobile CR0301
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