# ID 70020

Dynamical position lag exceeds range.
Description | During axis movement, the position lag exceeded a permissible limit for the current motion velocity. Dynamic tracking/following error monitoring ([FCT-A1// Section: Description]) calculates the permissible position lag as a function of motion velocity when an axis is moved. It is configured individually in the lists for axis parameters ( P-AXIS-00167, P-AXIS-00168, P-AXIS-00169, P-AXIS-00170, P-AXIS-00172, P-AXIS-00176 and P-AXIS-00191). The NC control offers two different methods, with which the maximum permissible position lag can be calculated:

Type 1: Standard method – uses a parameter-definable filter

Type 2: Linear method – is based on a theoretical position lag

Possible causes of an impermissible position lag could be for example:

- Too large accelerations specified for the axis
- The presence of friction in the actuating system
- The axis is blocked and can not move freely
- Poorly set position controller (for gain factor see P-AXIS-00099)
- Drive type SERCOS: If different proportional gain values are used in the drives and the axis parameters.

Possible solutions:

- Reduce the command accelerations
- Ensure free movement of the axis
- Check setting (gain factor Kv, see P-AXIS-00099) of position controller
- If necessary, change the parameterization of the dynamic tracking/following error monitoring ([FCT-A1// Section: Axis parameters])

Response | Class | 8 | Controlled halt of the axis, the control loop is open.
Solution | Class | 6 | Check position controller, freedom of movement; smaller accelerations
Parameter | %1: | Logical axis number [-]
Logical axis number of affected axis see P-AXIS-00016
%2: | Drive type [-]
Drive type of concerned axis, see P-AXIS-00020
%3: | Current value[0.1 µm or 0.0001°]
Current position lag
%4: | Upper limit value[0.1 µm or 0.0001°]
Maximum allowed position lag
%5: | Block number [-]
Block number of the NC program, in which the error occurred
Error type | 11, Error message from position controller.