Zero Offset External Via System Frames - Siemens SINUMERIK 840D sl Function Manual

"Scratching" means workpiece and tool measuring. The position of the workpiece in relation
to an edge, a corner or a hole can be measured. To determine the zero position of the
workpiece or the hole, position setpoints can be added to the measured positions in the WCS.
The resultant offsets can be entered in a selected frame. In tool measuring, the length or radius
of a tool can be measured using a measured reference part.
Measurements can be taken via operator actions or measuring cycles. Communication with
the NCK takes place via predefined system variables. In the NCK, the calculation is made by
using a HMI operator action to activate a PI service, or by using a part-program command from
the measuring cycles. A tool and a plane can be selected as a basis for the calculation. The
calculated frame is entered in the result frame.
10.5.8.2

Zero offset external via system frames

Zero offset via PLC or part program
The amount of the external zero offset can be specified through HMI and PLC via BTSS or
programmed in the part program via the axis-specific system variable $AA_ETRANS [<Axis>]
= <Value>.
Activation
The activation of the external zero offset takes place through the interface signal:
DB31, ... DBX3.0 (accept external zero offset)
Behavior
After the activation the respective specified axis-specific amount of the external zero offset is
traversed outside for each axis with the next possible traversing block.
Next possible means that enough dynamic reserves must be available for the respective axis
for traversing the zero offset. If the axis is traversed in the next traversing block after activation
owing to its programming with the maximum speed, dynamic reserve is no longer available for
traversing the external zero offset.
Together with the continuous path mode G64 the traversing of the offset can stretch over
several part program blocks.
Zero offset via system frame
The external zero offset can then also be managed and activated by the functionality described
above via the system frame $P_EXTFRAME .
configuring
The configuring of the external zero offset is done via the system frame $P_EXTFRAME via
bit1 = 1 in the machine data: MD28082 $MC_MM_SYSTEM_FRAME_MASK = 'B0010'
The amount for the external zero offset can be specified manually via the HMI user interface
and the PLC user program via BTSS or programmed in the part program via the axial system
variable $AA_ETRANS[<Axis>].
Activation
The activation of the external zero offset takes place through the interface signal:
DB31, ... DBX3.0 (accept external zero offset)
Behavior
Upon activation of the external zero offset the traversing movements of all axes, except
Basic Functions
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
K2: Axis Types, Coordinate Systems, Frames
10.5 Frames
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