Siemens SINUMERIK 840D sl Function Manual page 1396

Detailed description
2.12 Block descriptions
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.
Recommendation: Use the extended FB 7 in place of FB 4.
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 an instance DB from the user area.
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 signal 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
FB 4 can start PI services only if the 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 OB100.
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Basic logic functions: PLC basic program solution line (P3 sl)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0