HEIDENHAIN TNC 122 Technical Manual - Manual (Page 26)

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TNC 122 9 Machine Integration 25
Rapid traverse control
For operation at rapid traverse, both programmed and manually actuated, MP80 determines the
analog supply voltage for the motor controllers. The machine's circuit diagram will indicate whether
the controller input should be supplied by external analog voltage or the analog voltage of the
control, and whether amplified tachometer signals are used.
Programming of rapid traverse: Select the axis, enter the value, press and hold the machine rapid
traverse button, confirm by pressing the "ENT" key.
External analog voltage for rapid traverse at the controller input (MP80 =1):
If MP80 = 1, the controller will be switched to external analog voltage supply when the machine
axes are moving at rapid traverse. The control loop remains closed although the control is not
monitoring it. The control does not begin monitoring the loop until the axis comes within a certain
distance to the target position. This distance is defined in MP4210 and is transmitted to the PLC. To
resume feedback control, the PLC resets the "rapid traverse" output (X41, pin 16).
In order to ensure that servo lag monitoring does not respond during rapid traverse, the control
operates internally with a rapid traverse from MP1010.3-5 and a “servo lag” is internally adjusted
such that it remains within the permissible range of servo lag monitoring (floating nominal value).
The servo lag internal adjustment is defined with machine parameter MP1850 such that no
oscillations result. The rapid traverse in MP1010.3-5 must correspond with the actual rapid traverse.
The correct setting for the internal adjustment can be checked in a special display (activated with
MP7322) showing the actual feed rate, the analog voltage of the control and the internal nominal
servo lag as a percentage of the actual servo lag.
If the display sways between 80% and 120% this results in oscillations within the control. These
oscillations can be prevented by properly setting MP1850. The setting in MP1010.x is correct if the
display remains stable at approx. 100%. The behavior of the floating nominal value can also be
measured at the analog output with an oscilloscope.
Analog voltage of the control for rapid traverse at the servo input of (MP80 = 2):
If the feedback input is supplied from the control during rapid traverse and the tachometer voltage
must be switched, then enter the value 2 in MP80. In MP1010.3-5 enter the same rapid traverse
rate as the machine had with the TNC 121.
MP1010 Feed rate at 10 V analog voltage
Input: 80 to 30 000 [mm/min]
MP1010.0 Axis X
MP1010.1 Axis Y
MP1010.2 Axis Z
Rapid traverse for amplified tachometer signals or external rapid traverse voltage
Input range: 80 to 30 000 [mm/min]
MP1010.3 Axis X
MP1010.4 Axis Y
MP1010.5 Axis Z