Position Or Servo Lag Monitoring - HEIDENHAIN iTNC 530 Service Manual

3.3.1 Position or servo lag monitoring

The axis positions are monitored by the iTNC 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 Positioning error is generated: The machine
stops.
You can clear this message with the CE key. An actual-to-nominal value transfer is then executed
for the respective axis.
If the second limit is exceeded, the error message Excessive servo lag in <axis> appears.
The control-is-ready signal output is reset. The EMERGENCY STOP chain is interrupted.
MP1410.x
MP1420.x
MP1710.x
MP1720.x
The list does not claim to be complete; ask your machine tool builder!
Possible
You may add your own experiences!
causes of error
When the control is switched off, the actual position of the axes is saved with an absolute
Difference between
encoder. During switch-on it is compared with the position values read by the encoder.
position at switch-
on and shutdown
If the positions differ by more than the difference defined in MP 1146.x, a pop-up window
appears with both positions. The new position can be confirmed with a soft key. If it is not
confirmed, the error message Check the position encoder <axis> appears.
3 – 664
Position monitoring for the operation with velocity feedforward control (NC
stop)
Position monitoring for the operation with velocity feedforward control
(EMERGENCY STOP)
Position monitoring for the operation with following error (NC stop)
Position monitoring for the operation with following error (EMERGENCY
STOP)
Blunt tool
Excessive machining feed rate
Spindle speed too low
Insufficient lubrication
General mechanical stiffness
Vibration load on the machine
With analog axes: excessive offset (drift), faulty tachometer or carbon brushes
Hardware error in the control loop
Scanning head loose
Encoder defective
Encoder cable defective
HEIDENHAIN Service Manual iTNC 530