Siemens SINUMERIK 840C - Manual (Page 634)

Current
control loop
09.95
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Siemens AG 2001 All Rights Reserved 6FC5197– j AA50 9–13
SINUMERIK 840C (IA)
You can set the filters or controller parameters as required by means of
“Contr.para FDD” or “Contr.para MSD”. You should check their effect immediately
after a further measurement. You can also determine from the Bode diagram
whether the available high dynamic response of the SIMODRIVE drives is being
fully utilized. You should measure values of between 1 and 2 kHz in the current
controller frequency response; the speed control loop reaches several hundred
Hertz in feed drives and at least 100 Hz in main spindle drives.
Optimum setting of the current controller can be ensured when a standard motor/
power section combination is input; the control need therefore only be measured
when motors or power sections are used which are not contained in the standard
lists or for servicing purposes.
The speed controller parameters are roughly preset for standard motor/power
sections based on the motor moment of inertia. You must optimize the speed
control loop according to the mechanical properties of the axis during start-up.
The response of the position control which has a decisive effect on the contour
should be as linear as possible, particularly in the range up to 10 Hz. Resonance
in the position controller frequency response always causes overshoots on the
contour.
9.2.1 Current control loop (axis and spindle – as from SW 3)
You can select the measuring function for the current control loop with this soft-
key.
Note Test measurements on the current control loop can be performed on digital feed
and main spindle drives with SW 4 and higher. With SW 3, this function can still
only be applied to digital feed drives.
Explanation Test measurements on the current control loop are based purely on the reference
frequency response measurement = frequency response. The torque-produc-
ing current actual value measured quantity = current actual value is always
measured.
The enable commands must be implemented either internally or with PLC or
with PLC without NC (SW 4 and higher).
The following applies to the upper and lower traversing range limits:
The specified limit values define the permissible traversing range during start-up.
With a referenced axis/positioned spindle, the limit applies to the axis position/
spindle position at the start of the movement and, with a non-referenced axis/
positioned spindle, to the axis/spindle position at the start of the first test move-
ment after the machine is switched on.
The value 0.0 corresponds to zero traversing limits, i.e. the
traversing range is not monitored.
The current axis/spindle position is displayed in the “Position actual value/abso-
lute position” field.
9 Drive Servo Start-Up Application (as from SW 3) 07.97
9.2.1 Current control loop (axis and spindle – as from SW 3)