Siemens SINUMERIK 840D sl, Function Manual

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Detailed description
2.12 Block descriptions
Basic logic functions: PLC Basic program powerline (P3 pl)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
125
2.12.4 FB 4: PI_SERV General PI services
Description of Functions
FB PI_SERV can be used to start program-instance services in the NCK area.
A program section, which carries out a particular function (e.g., with tool management,
search for empty location in a magazine), is executed in the NCK by making a request via
the PI service.
Every FB 4 call must be assigned a separate instance DB from the user area. The
documentation for using the multii-instance capability is contained in the STEP7
descriptions.
The specified service is referenced via the "PIService" parameter. The selected PI service is
supplied via the freely assignable additional input variables with varying data types (Addr1 to
Addr4 for strings, WVar1 to WVar 10 for integer or word variables).
A job is started when FB 4 is called by means of a positive edge change at control input Req.
Successful execution of the job is displayed by means of a logical "1" in status parameter
"Done". Any errors are indicated by Error and State.
The "PI" data block (DB16) contains internal descriptions of the possible PI services. A name
must then be assigned to this DB in the symbol list. On calling the FB 4, "DB-Name.PI-
Name" is transferred as the actual parameter for "PIService".
The execution of the PI service extends over several PLC cycles (generally 1 to 2). The
block can be called up in cyclic mode only.
Note
The FB 4 can start PI services only
if the basic program parameter NCKomm has been set to "1" (in OB100: FB 1, DB 7). The
call is permitted only in cyclic program OB 1.
Declaration of the function
FUNCTION_BLOCK FB 4
VAR_INPUT
Req : BOOL ;
PIService : ANY ;
Unit : INT ;
Addr1 : ANY ;
Addr2 : ANY ;
Addr3 : ANY ;
Addr4 : ANY ;
WVar1 : WORD ;
WVar2 : WORD ;
WVar3 : WORD ;
WVar4 : WORD ;