P3: Basic PLC Program for SINUMERIK 840D sl
13.13 Block descriptions
Basic Functions
940 Function Manual, 09/2011, 6FC5397-0BP40-2BA0
13.13.3 FB 3: PUT write NC variables
Function
The PLC user program can write variables in the NCK area using FB PUT. The FB is multi-instance-capable.
Every FB 3 call must be assigned a separate instance DB from the user area.
When FB 3 is called with a positive signal edge change at control input Req, a job is started to overwrite the NC
variables referenced by Addr1 to Addr8 with the data of the PLC operand areas locally referenced by SD1 to
SD8. Successful completion of the write process is indicated by a logical "1" in status parameter "Done".
The write process lasts for several PLC cycles (normally 1-2). The block can be called up in cyclic mode only.
Any errors are indicated by Error and State.
In order to reference the NC variables, all required variables are first selected with the "NC VAR selector" tool
and generated as STL source in a data block. A name must then be assigned to this DB in the symbol table.
"DB name.S7 name" is transferred as the actual parameter of the NCK variable address (Addr1 to Addr8) when
FB 3 is called.
Variable addressing
For some NC variables, it is necessary to select area no. and/or line or column in the NC VAR selector. For these
variables it is possible to select a basic type, i.e. area/column/row is filled with "0" by default.
The contents of the area number, line and column specified by the NC VAR selector are checked for a "0" in the
FB. If a "0" is present, the value is transferred to the input parameter. The user must supply the required
parameters (UnitX/ColumnX/LineX) before calling Here unit corresponds to area no., column to column and line
to row.
Machine data, GUD
In order to define machine data and GUDs without a password, the protection levels of the data you want to
access must be redefined to the lowest level.
Reference:
• Commissioning manual; Chapter: "Protection levels concept"
• Programming Manual, Job Planning; Chapter: "Define protection levels for user data"
NCK variables within one group can be combined in a job:
NOTICE
FB 3 can only write NC variables if basic program parameter "NCKomm" has been set to
"1" (in OB 100: FB 1, DB 7). The call is permitted only in cyclic program OB1. An
assignment for all parameters with Req = 0 is also permitted in OB 100.
When channelspecific variables are written, only variables from one and the same
channel may be addressed via Addr1 to Addr8 in a job (FB 3 call).
In areas V and H, different logic axis numbers must not be assigned in a single job.
(Failure to observe this rule results in Error:= TRUE, State:= W#16#02).
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