Siemens CP 1543-1, Руководство по эксплуатации, Страница: 60 / 90

Configuration, programming
4.7 FTP communication
CP 1543-1
60
Operating Instructions, 12/2019, C79000-G8976-C289-08
Parameter Type Value / meaning Supply
WRITEACCESS BOOL
•
0: The user program has write
access rights for the file DBs
on the S7 CPU.
• 1: The user program has no
write access rights for the file
DBs on the S7 CPU.
During the configuration of the DB, the bit
is set to an initialization value.
Recommendation:
Whenever possible, the bit should remain
unchanged! In special situations, adapta-
tion during operation is possible.
ACT_LENGTH DINT Current length of the user data
area.
The content of this field is only
valid when EXIST = 1.
The current length is updated following
write access.
MAX_LENGTH DINT Maximum length of the user data
area (length of the entire DB less
20 bytes header).
The maximum length should be specified
during configuration of the DB.
The value can also be modified by the
user program during operation.
FTP_REPLY_CODE INT Unsigned integer (16-bit) contain-
ing the last reply code from FTP
as a binary value.
The content of this field is only
valid when EXIST = 1.
Updated by the FTP protocol handler with
the FTP command processing of the
server.
DATE_TIME DATE_AND_TIME Date and time of the last modifica-
tion to the file.
The content of this field is only
valid when EXIST = 1.
The current date is updated following a
write access.
If the function for forwarding the time of
day is used, the entry corresponds to the
time that was passed on.
If the function for forwarding the time of
day is not used, a relative time is entered.
The reference is the startup time of the
CP (initialization value: 01.01.1994
00:00h).
Evaluating the "LOCKED" and "NEW" status bits from the FTP_CMD program block
● In version 1.2 of the "FTP_CMD" program block, the status bits "LOCKED" and "NEW" of
the FILE_DB_HEADER are not evaluated.
With the functions of the FTP server or when using the same file DB, the possibility of
multiple simultaneous access to the same data area cannot be excluded. This can lead to
data inconsistency.
● As of version 1.5 of the "FTP_CMD" program block, the status bits "LOCKED" and "NEW"
of the FILE_DB_HEADER are set correctly. The two status bits are evaluated. Version 1.5
is available as of STEP 7 Professional V12 SP1.
Note
Avoiding data inconsistency
Make sure that you do not access the same file DB more than once at the same time.