Delta Tau GEO BRICK LV User Manual

 

 

Abort 

The A abort command breaks into the executing trajectory immediately, and brings all motors in the 
coordinate system to a controlled stop, each at its own deceleration rate as set by Ixx15 for the motor.  
The stop is not necessarily at a programmed point (and probably will not be), and it is not necessarily 
even along the programmed path (and probably will not be).   

Segments and synchronous M-variable assignments already in the lookahead buffer are discarded; they 
cannot be recovered.  Although the program could be resumed with an R or S command, execution would 
miss all of the discarded segments from the lookahead buffer.  Special recovery algorithms would be 
required to resume operation, so the abort command is not recommended except for stopping quickly 
under error conditions. 

Kill All 

The <CTRL-K> kill-all command breaks into the executing trajectory immediately, and disables all 
motors on the Turbo PMAC by opening the servo loops, forcing zero-value command outputs, and 
disabling the amplifiers.  Motors will coast to a stop in the absence of brakes or regeneration circuits. 

Segments and synchronous M-variable assignments already in the lookahead buffer are discarded; they 
cannot be recovered.  Although the program could be resumed after re-enabling the servo loops with an R 
or S command, execution would miss all of the discarded segments from the lookahead buffer.  Special 
recovery algorithms would be required to resume operation, so the “kill-all” command is not 
recommended except for emergency conditions. 

Note that the motor-specific K kill command is not permitted when the motor is in a coordinate system 
that is executing a motion program.  The program must first be halted, usually with an A abort command. 

If the lookahead buffer has been sized larger than what is required simply for the actual lookahead, it will 
contain historical data that can be used for reversal along the programmed path.  This capability gives the 
system a “retrace” capability, allowing it easily to go backwards along the already executed path.  The 
key command to be used in reversal is the < backup command, which causes the coordinate system to 
start execution in the reverse direction through the segments in the lookahead buffer. 

Back-up Command 

If the < command is given while the coordinate system is in normal forward execution in the lookahead 
buffer, Turbo PMAC will internally generate a \ “quick-stop” command to halt the forward execution, 
then start reverse execution. 

The < command can also be given after execution of the program has been halted with a \ quick-stop 
command.  It cannot be given after stopping with an / end-of-block, Q quit, S single-step, A abort or 
<CTRL-K> kill-all command, or an automatic error termination. 

Reverse Execution 

Execution in the reverse direction will observe the position, velocity, and acceleration limits, just as in the 
forward direction.  Note, that if Isx20 is set to 1, limits are not observed in either the forward or reverse 
direction.  In this mode, the lookahead buffer is simply used to buffer points to enable reversal, without 
the computational overhead of actual lookahead calculations.  This mode is appropriate for EDM 
applications, which require quick reversal, but not careful acceleration limiting. 

If not stopped by another command, reverse execution will continue until it reaches the beginning (oldest 
stored point) of the lookahead buffer.  It will stop automatically at this point with a controlled 
deceleration within the acceleration constraints.  The oldest stored point in the lookahead buffer will 
never be from before the first point in the current continuous blended motion sequence.  This means that 
you cannot reverse into, past, or through any of the following: