Siemens SINUMERIK 840Di Function Manual page 790

Detailed Description
2.4 Frames
Programming basic frames
Basic frames can be read and written via the part program and via the OPI by operator
actions and by the PLC. However, only data management frames can be written by the OPI.
2.4.6.4 NCU global basic frames $P_NCBFR[n]
The number of global basic frames can be configured via machine data
MD18602 $MN_MM_NUM_GLOBAL_BASE_FRAMES.
There are a maximum of 16 global basic frames. All basic frames are stored as fields.
System variable $P_NCBFR[n] can be used to read and write the basic frame field elements.
The chained complete basic frame is not activated simultaneously when writing a basic
frame field element, but rather activation only takes place on execution of a G500,G54, to
G599 instruction. If the modified frame is to be active in every channel of the NCU, every
channel must execute a G500,G54 to G599 instruction. The variable is used primarily for
storing write operations to the basic frame from HMI or PLC. These frame variables are
saved by the data backup.
Current NCU global basic frames $P_NCBFRAME[n]
System variable $P_NCBFRAME[n] can be used to read and write the current global basic
frame field elements. The resulting total basic frame is calculated by means of the write
process in the channel. The modified frame is activated only in the channel in which the
frame was programmed. If the frame is to be modified for all channels of an NCU,
$P_NCBFR[n] and $P_NCBFRAME[n] must be written simultaneously. The other channels
must then activate the frame, e.g., with G54. Whenever a basic frame is written, the
complete basic frame is calculated again.
Programming global frames
Global frames are programmed analogously, as are channel-specific frames, i.e., global
basic frames are programmed with $P_NCBFR[n] and global settable frames with
$P_UIFR[n].
Geometry axis, channel axis and machine axis identifiers can be used as axis identifiers for
frame program commands. If there is no machine axis for the channel axis on the NCU,
programming with channel axis identifiers is rejected with the alarm 18314 "Frame: Type
conflict". Channel-specific frames can be programmed with geometry axis, channel axis and
machine axis identifiers. If there is no corresponding channel axis for the machine axis on
the NCU, programming with machine axis identifiers is rejected with the alarm 18314
"Frame: Type conflict". If frame components are applied to a machine axis or a channel axis,
which is also a geometry axis, the corresponding geometry axis components will also be
simultaneously modified.
Example:
$P_NCBFR[0] = CTRANS( ax1, 10 )
$P_NCBFR[0] = CTRANS(x, 10)
$P_NCBFR[0, ax1, FI ] = 0.1
$P_NCBFR[0, x, FI] = 0.1
2-60
Axis Types, Coordinate Systems, Frames (K2)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0