Siemens SINUMERIK 840Di Function Manual page 825

If a current frame has been specified as a target frame, then the new complete frame
becomes active at the preprocessing stage. If the target frame is a data management frame,
then the frame is not operative until it is explicitly activated in the part program.
The function does not set any alarms, but returns the error codes via the return value. The
cycle can react according to the error codes.
2.4.9 Functions
2.4.9.1 Setting zeros, workpiece measuring and tool measuring
PRESET is achieved using HMI operator actions or measuring cycles. The calculated frame
can be written to system frame SETFRAME. The position setpoint of an axis in the WCS can
be altered when the actual-value memory is preset.
"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.
2.4.9.2 Zero offset external via system frames
Previous function:
The zero offset external is either defined by the PLC via the OPI or programmed in the part
program by the axis variable $AA_ETRANS[axis] = value. This zero offset is activated by the
PLC via a VDI signal.
After the PLC has activated the offset, every axis compensation value is applied with the
next block. With G64, in certain circumstances this could also be multiple blocks, if there is
no Stop at the block end.
Functional expansion:
With SW package 6 and higher, the zero offset external can be managed and enabled via a
system frame.
The system frame is configured with bit 1 in machine data
MD28082 $MC_MM_SYSTEM_FRAME_MASK = 'B0010'.
If this bit is set, the system function will only use the system frame, disabling the existing
functionality. Values are written by the PLC (OPI) or, in the part program, with axial variables
$AA_ETRANS[axis].
As previously, activation is by the PLC, via an axial VDI signal.
Axis Types, Coordinate Systems, Frames (K2)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
Detailed Description
2.4 Frames
2-95