
B-63354EN/04 IV. OPERATION 6.15i
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i DATA SERVER FUNCTIONS
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6.1.8.1 How to use the buffer mode
The buffer mode is designed to handle an NC program larger than the
capacity of the data server board built-in hard disk. This mode can be
used with DNC operations (Section 5.6) including a DNC operation by
a subprogram call (M198) (Section 5.7).
In the buffer mode, the Oxxxx file called during a DNC operation or by
subprogram calling is a file list, which is a list of file names arranged in
the sequence in which they are to be called. In this mode, the data
server board calls the files specified according to this file list
sequentially and supplies data from them to the NC. (See the
following figure.)
As seen from the above figure, the contents of the files (file1 to file5)
specified in the file list in the host computer are fetched into the data
server board built-in hard disk, using the FTP, then the data is supplied
to the CNC. In the buffer mode, after the CNC requests the data server
to read the NC program, the specified file list is read from the host
computer, and the contents of the first file in the file list are read, then
the data is supplied to the CNC. Note, therefore, that a time lag occurs
between the read request and the data supply sequence. In addition,
while data is being supplied from one of the areas to the CNC, data is
fetched into the other area, using the FTP. Therefore, the original data
must be divided to such a size that the resulting two consecutive files
can fit on the data server board built-in hard disk.
When a data transfer from one of the areas to the CNC is completed, if
the FTP communication with the other area has not ended, another data
supply sequence cannot be performed, and therefore, the program call
ends in an error. This error can be suppressed, using a parameter,
however. See Section 5.3, "Parameters," of Part III, "Setting," for
details.
For a DNC operation by a subprogram call (M198), the name of the file
list must be O-number format. For other DNC operations, however, the
name of the file list is arbitrary.
The name of each file specified in the file list can be any name
permitted in the host computer, provided that it does no exceed 255
alphanumeric characters. In the file list, each file name must be
Contents
of Oxxxx
file1
file2
file3
file4
file5
Hard disk
get (FTP)
Program
calling
Oxxxx
Oxxxx
file1
file2
file3
file4
file5
file1
file2
file3
file4
file5
Hard disk
rea
rea B
CNC
Data server Host com
uter