Technical data

Linkage with PLC
134 VIPA GmbH CP486 ⋅ 00/14
6.3.3.15 Set File Pointer
Parameterization of FB3: F-Nr 66 ($42 hex)
DOSP POS (high-order byte), handle (low-order byte)
QT/N no. of DB with file pointer
QANF position of file pointer in DB
QLAE length of data record (2 words)
Content of DB: DW1 high-order word of file pointer
DW2 low-order word of file pointer
Parameter:
POS: 0 abs. position of file start
1 rel. position from current position (signed)
2 rel. position from file end (signed)
Note:
Note that the value of the file pointer is always to be regarded as the specification of a byte-
position.
Length of a file can be detected by means of this function if 02 is entered as function code
and 0 as new relative position of file end. Finally, the position being at the same time the
number of data can be achieved via "get file pointer".
6.3.3.16 Get File Pointer
Parameterization of FB5: F-Nr 194 ($C2 hex)
DOSP handle
Parameterization of FB6: ZT/N no. of DB for required data
ZANF target position in DB
ZLAE 2
Content of DB: DW1 A-NR F-Nr
DW2 number of words being read
DW3 high-order word of file pointer
DW4 low-order word of file pointer
The file pointer is returned again as a doubleword. Thus, the digit 2 is also to be specified as
number of data. Note that the value of the file pointer is always to be regarded as the
specification of a byte-position.