240/641 Bosch Rexroth AG | Tightening Technology 3 608 878 300
System 350 | 3 608 878 300/2019-03
6.2.4 Opening and closing the FTP connections for results output
Opening and closing the FTP connections is initiated by the tightening system. Basically, there are two
different cases:
• Data transfer after process end, independent of the tightening process, single channel or tightening
application (asynchronous data transfer)
• Data transfer before process end of the tightening (synchronous data transfer)
Data transfer after
process end
With data transfer after process end (asynchronous), the results data records are buffered by being
stored in the CF350 mass storage during the tightening process, i.e. before CyCmp. The data are
transferred independently of the tightening cycle. The tightening function is not impaired, as long as there
is enough space in the mass storage for new results files (see page 258). All results files are transferred
from the mass storage to the FTP server in blocks. An FTP connection is established if results data are
available in the mass storage. The error signal FtpF will be set to 1 if a disruption occurs during the
transfer to the FTP server. This signal will be automatically reset to 0 after the next successful data
transfer.
Data transfer before
sequence end
In synchronous data transfer, an FTP connection is opened for each program that is started with a specific
start signal (Prog0 to Prog5) and each application that is started with a specific start signal (FO1Cw to
FO8Cw). For a total of 8 different start signals for up to 8 parallel applications, up to 8 FTP connections
can be established. An additional connection for transferring the single-channel results is opened, as well.
Thus, up to 9 FTP connections can be open simultaneously between the tightening system as FTP client
and the FTP server.
With data transfer before process end (synchronous), the results data records are not buffered in the
mass storage. A separate FTP connection is established to transfer the results from the controller's buffer.
The tightening program or application can be restarted only after data transfer is completed.
The opened FTP connection remains active until it is either closed by the FTP server or a disruption
occurs. Such a connection is only reopened if needed. If transfer via Ethernet is not possible, the FtpF =
1 (FTP error) and NF = 0 (No Fault) error signals will be generated and correspondingly entered in the
error list.
Data transfer before
process end via one
FTP connection
(single session)
Some FTP servers (partner controller) cannot support multiple sessions or are also used by other network
participants. Thus, it is sometimes preferable to use as few FTP sessions as possible.
The Single session setting in the BS350 operating system allows to open just one FTP connection even
when transferring data before process end. The FTP connection is only established if results data are
available for transfer. The connection is immediately closed after the transfer has been completed.
In case of parallel applications, or if applications and single channels are operated simultaneously within
one tightening cell, two (or more) results may still have to be transferred at the same time.
The results are not bundled during synchronous results output. Moreover, the communication unit
attempts to establish several FTP connections in this case. If the FTP server permits this, the results will
be transferred parallel. If only one FTP connection is accepted, the communication unit will continue to
attempt to establish a connection for a second (and every additional) results file within a set time interval
(timeout). During this time, no process end signal (CyCmp) is set for these tightening(s).
If it is not possible to transfer the results file within the set time frame, the FtpF = "1" (KE FTP error) and
NF = "0" (KE no fault) signals are output.
The type of transfer for the results output is set in the operating system under FTP transfer settings in
the Results (see page 225)
index card.
The FTP server must be able to support multiple sessions. Keeping the FTP connections open ensures
the fastest possible data transfer.
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