Channel Basic Frames $P_Chbfr[N] - Siemens SINUMERIK 828D Function Manual

K2: Axis Types, Coordinate Systems, Frames
10.5 Frames
10.5.5.3

Channel basic frames $P_CHBFR[n]

The number of basic frames in the channel can be configured via the machine data:
MD28081 $MC_MM_NUM_BASE_FRAMES (number of basic frames (SRAM))
The minimum configuration is designed for at least one basic frame per channel. A maximum of 16 basic frames
per channel is possible. In addition to the 16 basic frames, there can also be 16 NCU-global basic frames in the
channel.
System variable $P_CHBFR[n] can be used to read and write the basic frame field elements. While writing a
basic frame field element, the chained total frame is not activated. Instead, the activation takes place only after a
G500,G54..G599instruction is executed. The variable is used primarily for storing write operations to the basic
frame on HMI or PLC. These frame variables are saved by the data backup.
Current channel basic frames $P_CHBFRAME[n]
System variable $P_CHBFRAME[n] can be used to read and write the current channel basic frame field
elements. The resulting total basic frame is calculated by means of the write process in the channel. Whenever a
basic frame is written, the complete basic frame is calculated again.
Basic frame in channel $P_UBFR
The system variable is retained for reasons of compatibility, although it is redundant for the $P_CHBFR[0]
variables.
The basic frame with field device 0 is not activated simultaneously when writing to the predefined $P_UBFR
variable, but rather activation only takes place on execution of a G500,G54,.G599instruction. For NCU global
frames, the changed frame only becomes active in those channels of the NCU, which execute a
G500,G54..G599instruction. The variable is used primarily for storing write operations to the basic frame on HMI
or PLC. The variable can also be read and written in the program.
$P_UBFR is identical to $P_CHBFR[0]. One basic frame always exists in the channel by default, so that the
system variable is compatible with older versions. If there is no channel-specific basic frame, an alarm is issued
at read/write: "Frame: Instruction not allowed" is output on a read or write access.
Current first basic frame in the channel $P_BFRAME
The system variable is retained for reasons of compatibility, although it is redundant for the $P_CHBFRAME[0]
variables.
The predefined frame variable $P_BFRAME can be used to read and write the current basic frame with the field
device of 0, which is valid in the channel, in the part program. The written basic frame is immediately included in
the calculation. In the case of NCU global settable frames, the modified frame acts only in the channel in which
the frame was programmed. If the frame is to be modified for all channels of an NCU, $P_UBFR and
$P_BFRAME must be written simultaneously. The other channels must then activate the corresponding frame,
e.g., with G54.
$P_BFRAME is identical to $P_CHBFRAME[0]. The system variable always has a valid default value. If there is
no channel-specific basic frame, an alarm is issued at read/write: "Frame: Instruction not allowed" is output on a
read or write access.
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.
Basic Functions
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Function Manual, 09/2011, 6FC5397-0BP40-2BA0