Setting up Compax3 C3F_T40
78 192-121102 N04 June 2008
4.1.12. Following error limit
The error reaction upon a following error can be set:
Possible settings for the error reaction are:
No response
downramp / stop
Downramp / switch to currentless (standard setting)
The following error is a dynamic error.
The dynamic difference between the setpoint position and the actual position
during a positioning is called the following error. Do not confuse this with the static
difference which is always 0; the target position is always reached exactly.
The change of position over time can be specified exactly using the parameters
jerk, acceleration and speed. The integrated Setpoint value generator calculates
the course of the target position. Because of the delay in the feedback loop, the
actual position does not follow the setpoint position exactly. This difference is
referred to as the following error.
In joint operation of several servo controllers (e.g. master controller and slave
controller), following errors lead to problems due to the dynamic position
differences, and a large following error can lead to positioning overshoot.
If the following error exceeds the specified following error limit, the ”following error
time” then expires. If the following error is even greater than the following error limit
at the end of the following error time, an error is reported.
If the following error falls short of the following error limit, a new following error time
is then started.
The following error can be minimized with the help of the extended (advanced)
control parameters, in particular with the feed forward parameters.
1: Following error limit [parameterized unit]
2: Tracking error time
ERROR:Error output of positioning modules
QUIT:Ackn with MC_Reset module
4.1.13. Maximum permissible speed
The limitation of the speed controller is deduced from the maximum permissible
speed. In order to ensure control margins, the speed is limited to a higher value.
The speed setpoint value is actively limited to 1.1 times the given value.
If the speed actual value exceeds the preset maximum permissible speed by 21%
(=”switching off limit speed”), error 0x7310 is triggered.
Disadvantages
caused by a
following error
Error message
Minimizing the
following error
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