Basic Characteristics RAPID

Error handling
The start of the search, i.e. when the I/O signal is ready to react, is not, in this case, the
programmed destination point of the previous positioning instruction, but a point along
the real robot path. Figure 2 illustrates an example of something that may go wrong
when zone data other than fine is used.
The instruction SearchC should never be restarted after the circle point has been
passed. Otherwise the robot will not take the programmed path (positioning around the
circular path in another direction compared with that programmed).
Start point with
zone data z10
Start point with
zone data fine
Search object
Figure 2 A match is made on the wrong side of the object because the wrong zone data was used.
Typical stop distance using a search velocity of 50 mm/s:
- without TCP on path (switch \Stop) 1-3 mm
- with TCP on path (switch \PStop) 12-16 mm
An error is reported during a search when:
End point
- no signal detection occurred
- more than one signal detection occurred – this generates an error only if the \Sup
argument is used.
Errors can be handled in different ways depending on the selected running mode:
Continuous forward
No position is returned and the movement always continues to the programmed
destination point. The system variable ERRNO is set to ERR_WHLSEARCH
and the error can be handled in the error handler of the routine.
Instruction forward
No position is returned and the movement always continues to the programmed
destination point. Program execution stops with an error message.
Instruction backward
During backward execution, the instruction just carries out the movement without
any signal supervision.
8-SearchC-4 RAPID Reference Manual