IAI PSEL, Operation Manual

Page: 176 / 1062

166
Part 2 Programs
z
QRTN (Set quick-return mode)
Command, declaration
Extension condition
(LD, A, O, AB, OB)
Input condition
(I/O, flag)
Command,
declaration
Operand 1 Operand 2
Output
(Output, flag)
Optional Optional QRTN 0 or 1 Prohibited CP
[Function] Set and cancel the quick-return mode.
(1) QRTN [Operand 1] = 0 (Normal mode)
Positioning is deemed complete when all command pulses have been output and the
current position is inside the positioning band.
* If a deceleration command is currently executed in the quick-return mode, the
system will wait for all command pulses to be output.
(2) QRTN [Operand 1] = 1 (Quick-return mode)
Positioning is deemed complete when “a normal deceleration command is currently
executed (excluding deceleration due to a stop command, etc.) or all command pulses
have been output” AND “the current position is inside the positioning band.” This setting is
used to perform other processing during deceleration, in conjunction with a PBND
command.
(Note 1) The quick-return mode will be cancelled when the program ends. (The positioning band set
by a PBND command will not be cancelled.)
(Note 2) If a given axis is used even once in the quick-return mode, the program will not release the
right to use the axis until the QRTN is set to “0” (normal mode) or the program ends. Any
attempt to use the axis from other program will generate an “Error No. C66, Axis duplication
error.”
(Note 3) Following a return from a normal deceleration command in the quick-return mode, the next
positioning will start after all command pulses for the previous positioning have been output.
Therefore, in the quick-return mode a simple reciprocating operation will require a longer tact
time because of the extra completion check. In this sense, this setting should be used only if
you wish to reduce the overall tact time by performing other processing during deceleration.
(Note 4) The quick-return mode represents very irregular processing. Therefore, be sure to revert to
the normal mode when the overlay processing is completed in the necessary section.
(Note 5) The quick-return mode cannot be used with a push-motion travel command or arc
interpolation command.
V
T
Command
pulses
Feedback
pulses
In the quick-return mode, the
set positioning band is valid
through this area.