ID 70020

Dynamic position lag exceeds maximum.

Description

When the axis was moved, 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 controller provides two different methods to calculate the maximum permissible position lag:

Type 1: Standard methods – Use a parameterisable filter

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

 

Possible causes of an excessive position lag may be, for example:

  • Accelerations specified too large for the axis
  • The occurrence of friction in the actuating system
  • The axis is blocked and cannot 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 parameterisation of the dynamic tracking/position lag 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; minor accelerations

Parameter

%1:

Logical axis number [-]

Logical axis number of affected axis, see P-AXIS-00016

%2:

Drive type [-]

Drive type of axis affected, 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 where the error occurred

Error type

11, Error message from position controller.