Siemens SINUMERIK 840Di Function Manual page 1287

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 2 can read NC variables only if basic program parameter NCKomm ="1" has been set (in
OB 100: FB 1, DB7). The call is permitted only in cyclic program OB1.
When channel-specific variables are read, only the variables of
one and the same channel may be addressed in one job (FB 2 call) via Addr1 to Addr8.
In areas V and H, different logic axis numbers must not be assigned in one job.
(Failure to observe this rule results in Error:= TRUE, State:= W#16#02).
NCK variables within one group can be combined in a job:
Group 1
Group 2
Group 3
The same rules apply to channels 3 to 10 as illustrated as examples in the above table in
groups 1 and 2.
Note
Especially when reading several long strings, the number of usable variables can be less
than 8.
Declaration
FUNCTION_BLOCK FB 2
VAR_INPUT
PLC Basic Program Solution Line (P3 sl)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
Area
C[1]
C[2]
V[.]
Req :
NumVar :
Addr1 :
Unit1 :
Column1 :
Line1 :
Addr2 :
Unit2 :
Column2 :
Line2 :
Addr3 :
Unit3 :
Column3 :
N B
N B
H[.]
BOOL ;
: INT ;
ANY ;
BYTE ;
WORD ;
WORD ;
ANY ;
BYTE ;
WORD ;
WORD ;
ANY ;
BYTE ;
WORD ;
Detailed Description
2.12 Block descriptions
Q T
Q T
2-93