8. DATA INPUT/OUTPUT
When a file already exists in a cassette or card, specifying N0 or N1 has
the same effect. If N1 is specified when there is no file on the cassette or
card, an alarm is issued because the first file cannot be found. Specifying
N0 places the head at the start of the cassette or card, regardless of whether
the cassette/card already contains files. So, no alarm is issued in this case.
N0 can be used, for example, when a program is written into a new
cassette or card, or when a previously used cassette or card is used once
all the files it contains have been erased.
If an alarm (file search failure, for example) is generated during file
search, the CNC does not issue an alarm immediately. However, a P/S
alarm (No.086) is issued if input/output is subsequently performed on that
Instead of sequentially searching for files by specifying actual file
numbers every time, the user can specify the first file number, then find
the subsequent files by specifying N–9999. When N–9999 is specified,
the time required for file search can be reduced.
Difference between N0
Alarm issue during file
File search using N–9999