Siemens SINUMERIK 840C - Manual (Page 870)

07.97 12 Functional Descriptions
12.12 Path dimension from PLC
12.12 Path dimension from PLC
General notes
You can traverse NC axes directly from the PLC user program via the command channel.
Machine control (control response, traverse response) and the displays of the NC remain
unchanged.
12.12.1 Execution of the function ” Path dimension from the PLC ”
The function ”Path dimension from the PLC” is activated by the PLC user program via the
command channel.
The following are entered in DB 41, e.g. starting at DW6 (m = 6 for the first ASS)
• In DW6: Function number (1 = static path dimension)
• In DW8: Source DB/DX number for the user data DB as well as selection of either DB or
DX
• In DW9: DW number as of which entries are to be made in the user data DB
The user must set up a user data DB. The following values can be written in these DBs:
• DWx Length in words (6)
• DWx+1 Channel number/axis number
• DWx+2 and
DWx+3
+/- position
• DWx+4 and
DWx+5
Axis feed
• DWx+6 G68, G94/95, G90/91.
The function ”Path dimension from the PLC” is activated via MD 5018 bit 5. In addition, the
number of user interfaces (ASS) must be entered in PLC MD 33 and the function activated
with PLC machine data bit 6026.1.
The path dimension is executed directly when the command channel strobe (DB41 DR0) is
detected by the NC.
Depending on the path condition in the command channel (G90/G91), either
• an incremental path dimension is traversed or
• an absolute position is approached.
The function ”Path dimension from the PLC” does not make allowance for
• zero offsets
• tool offsets
• DRF and PRESET shifts.
The axis feeds for the function ”Path dimension from the PLC” are likewise transferred via the
command channel. These feeds can be linear or rotational. The path conditions G94/P95 are
also passed down the command channel.
The required axis is specified as an axis number in the command channel. The axis must be
assigned to the mode group via whose NC channel the path dimension is traversed. You must
also parameterize the number of the NC channel.
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SINUMERIK 840C (IA)