Position Monitoring - HEIDENHAIN TNC 426 PB/M Technical Manual

6.11.1 Position Monitoring

6 – 158
The axis positions are monitored by the TNC as long as the control loop is
closed.
The input values for position monitoring depend on the maximum possible
following error (servo lag). Therefore the input ranges for operation with
following error and velocity feedforward are separate.
For both modes of operation there are two range limits for position monitoring.
If the first limit is exceeded, the error message EXCESSIVE SERVO LAG IN
<AXIS> appears. The machine stops.
You can clear this message with the CE key. An actual-to-nominal value
transfer is then executed for all axes.
As of NC software 280 476-13, an actual-to-nominal value transfer is carried
out only for the axis affected.
If the second limit is exceeded, the error message EXCESSIVE SERVO LAG IN
<AXIS> appears. The control-is-ready signal output is reset.
You cannot clear this message. You must restart the control to correct the
error.
7 7 7 7
In the machine parameters given below, define two range limits for position
monitoring in each operating mode.
7 7 7 7 Adjust the input values to the machine dynamics.
If blocked axes are the cause of the erasable error message EXCESSIVE SERVO
LAG IN <AXIS>, a nominal velocity value may freeze, since the machine axes
can no longer be moved:
7 7 7 7 In MP1150.0, specify the time after which the nominal velocity value is to
be deleted. After this time has expired, the actual position value is assumed
as nominal position value. Before this time has expired, the error message
cannot be cleared with the CE key. At this time the actual position value is
assumed as nominal value, and the nominal velocity value is deleted.
HEIDENHAIN Technical Manual TNC 426, TNC 430