Bosch Rexroth IndraDrive MPH-02 Functional Description page 274

6-62
Drive Control
Characteristics of Controller
F2037 Excessive position
command difference
F2028 Excessive deviation
F2036 Excessive position
feedback difference
2. Increase parameter S-0-0104, Position loop Kv-factor until instable
behavior (continuous oscillation) occurs.
3. Reduce parameter S-0-0104, Position loop Kv-factor until
continuous oscillation decreases automatically.
The value thus determined is the so-called "critical position loop Kv-
factor".
From the determined critical Kv-factor (see above) it is possible to derive
Setting a controller setting with the following characteristics:
• independent of changes at the axis because sufficient distance to
stability limit
• properties can be reliably reproduced in series machines
The position loop normally is checked by optimizing the lag error. To do
this, the following machine and application types have to be distinguished:
• high-end machine tools (e.g. grinding machines)
→ optimization with regard to a minimum lag error characteristic by the
highest possible Kv-factors
• standard positioning axes (e.g. press transfer)
→ Optimization with regard to a minimum lag error characteristic is not
required, the important thing is smoothest possible, jerk-free
positioning. This is achieved, among other things, by relatively low Kv-
factors resulting in very stable controller settings.
Diagnostic and Status Messages
Position command value (S-0-0047) and additive position command value
(S-0-0048) form the position command value that is first smoothed via the
subsequent position command value filter and then fine interpolated. If
necessary, the value is reduced to the bipolar velocity limit value
(S-0-0091). The result of the limitation is the effective velocity command
value (P-0-0048).
The position command values preset by the master are monitored in the
drive with regard to the following limit values:
• The position command value difference of the incoming position
command values within a SERCOS cycle must be smaller than the
bipolar velocity limit value (S-0-0091). If this position command value
difference between two successive position command values is
greater than the value in parameter S-0-0091, the F2037 Excessive
position command difference error message is generated and the
excessive position command value is stored in parameter P-0-0010,
Excessive position command value. The last valid position
command value is stored in parameter P-0-0011, Last valid position
command value. When modulo processing of the position data was
set the interpretation of the command values additionally depends on
the value in parameter S-0-0393, Command value mode. The
parameter should be set to "shortest distance" (value "0").
• The deviation of the actual position value from the position command
value is monitored by comparing an "actual position model value"
internally calculated in the drive to the real actual position value (= lag
error monitoring). If the difference of theoretical and real actual
position value permanently exceeds the value of parameter S-0-0159,
Monitoring window it is obvious that the drive cannot follow the
preset command value and the F2028 Excessive deviation error
message is generated.
• When 2 measuring systems (1 motor encoder and possibly external
length measuring system) are used simultaneously, the actual position
MPH-02, MPB-02, MPD-02
DOK-INDRV*-MP*-02VRS**-FK01-EN-P