Siemens SINUMERIK 840Di Function Manual page 1032

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. The possible
services are described in this section. 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 multi-
instance capability can also be applied in SW 3.7 and higher. Please refer to the STEP 7
Descriptions for more information.
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 logic "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
After communication between the PLC and NC (read/write NC variables, FB2, 3, 5, or PI
general services, FB4) has been aborted by POWER OFF, the start jobs must be deleted in
the first OB1 run after cold restart or reset (signal: Req = 0).
FB 4 can start PI services only if the basic program parameter NCKomm has been set to "1"
(in OB100: FB 1, DB7).
Declaration
FUNCTION_BLOCK FB 4
VAR_INPUT
2-120
Req :
PIService :
Unit :
Addr1 :
Addr2 :
Addr3 :
Addr4 :
BOOL ;
ANY ;
INT ;
ANY ;
ANY ;
ANY ;
ANY ;
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
Power Line Basic PLC Program (P3)