
B–63683EN/01
5. TOOL FUNCTION (T FUNCTION)
101
Once the pre–read T–code operation has been completed, the actual T
command is executed. The command is executed under usual T function
control. Once this T command has been processed, a subsequent pre–read
T–code is output. That is, a pre–read T code is output after the current T
code has been executed while the BTF and BTFIN signals have identical
states.
The pre–read T code processing is separate from the usual T code
processing. The machining program does not stop, instead continuing
even while the CNC is waiting for BTFIN. If the CNC is waiting for
BTFIN when the actual T command is executed, however, the program
enters the wait state.
G90G92X1800. Y1500. ;
G00X500. Y500. T301 ;
G26I50. J0. K8 ;
G72X800. Y500. ;
G26I50. J0. K8T201 ;
G00X1000. Y1000. T350 ;
L
T301 T201 T350Pre–read
T code
BTF
Executable
T code
T301 T201 T350
BTFIN
TF
TFIN
When all blocks have been pre–read, the CNC sets the pre–read T code
signal to 0 and inverts the BTF signal to indicate that it has reached the
end of the program. If necessary, the PMC should invert the BTFIN
signal.
If the RESET key is pressed, an emergency stop is instigated, or other
reset processing is executed during the output of a pre–read T code signal,
the CNC executes the following reset processing: Sets the bit of the BTF
signal to the bit of the BTFIN signal; Sets the pre–read T code signal to
0. The CNC clears the thirty blocks stored in the buffer, assuming that
they have already been executed.
To enable T–code pre–reading, a buffer that can store up to 30 blocks is
provided. T codes detected in the buffer are output as pre–read T code
signals. Operations and variable rewriting of custom macro statements
are not regarded as being CNC statements. They are processed before
being stored in the buffer. Some macro programs cannot be executed.
Examples
Reset processing
Executing a special
program