Siemens SINUMERIK 840D sl, Function Manual

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Detailed description
2.5 Optimization of the control
Basic logic functions: Velocities, Setpoint/Actual Value Systems, Closed-Loop Control (G2)
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Function Manual, 11/2006, 6FC5397-0BP10-2BA0
2.5.4 Position control with proportional-plus-integral-action controller
Function
In the default scenario, the core of the position controller is a proportional controller with the
above-mentioned upstream override options.
For special uses (such as for electronic gearing), an integral part can be connected. The
resulting proportional-plus-integral-action controller then corrects the error between setpoint
and actual positions down to zero in a finite, settable time period when the appropriate
machine data are set accordingly.
Caution
When the proportional-plus-integral-action controller is active, overshoots occur in the actual
position. In this instance, you must decide whether this effect is admissible or acceptable for
the application in question. Expert knowledge of control engineering and measurements
taken using servo trace are absolutely essential when using this function. If incorrect settings
are made for the relevant machine data, there is a risk of damaging the machine, due to
possible instability.
Background
The transfer function of the proportional-plus-integral-action controller is as follows:
*
5
V .
5
7
Q
V
K
R
: P component gain
T
n
: Integral time