HEIDENHAIN TNC 407 (243 020) Technical Manual - Manual (Page 251)

4-126
TNC 407/TNC 415/TNC 425 6 Display and operation 01.98
6 Display and operation
Machine parameters and PLC-markers can be used to influence the control behaviour for certain
functions. All machine parameters and PLC-markers which influence the display and the operation of
the control, and for which there is no separate section in this manual, are described in the section
"Display and operation" .
The display is divided into several "Windows" for optimum depiction of the information on the VDU-
screen.
Foreground mode
Background
mode
Program Text
Graphics
window
or additional
status display
PLC window
Status window
Soft keys
The VDU-screen displays can be changed by machine parameters and PLC-markers.
6.1 Machine datum
In the operating modes "Manual operation" and "Electronic handwheel", a workpiece datum can be
defined. NC positioning blocks normally refer to this datum. If a positioning block should be
referenced to the machine datum instead of the workpiece datum, this must be programmed in
M91. The distance of the machine datum to the scale datum is entered in machine parameter
MP960.x. All REF-referenced displays and positioning movements are referenced to the machine
datum.
If the NC positioning blocks should always be referenced to the machine datum, then the "datum
setting" can be disabled for the individual axes through MP7295.
With MP950.x you can define a further machine-referenced position. If you wish to reference to this
position in a positioning block, you must program it in with M92. MP950.x defines the distance from
this machine-referenced position to the machine datum.
M91 and M92 are non-modal.
MP7296 can be used to select whether a new datum point can be set with the "DATUM SET" soft
key or additionally with the axis keys.