Scanlab RTC6 PCIe Board - Page 794

RTC6 boards
Doc. Rev. 1.0.21 en-US
10 RTC6 Commands
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Comment • For programming the stepper motor signals, see Chapter 9.1.5 ”Controlling Stepper
Motors”, page 284.
• stepper_init immediately stops all previously started movements of the stepper motor
specified by the No parameter.
• The ENABLE signal Enable is merely forwarded and always correspondingly set, but has
no effect on internal operations.
• If Period > 0 and Dir  0, then stepper motor No starts a reference run with the
supplied CLOCK pulse period in the defined direction and the Init status gets set. The
first Clock pulse is only generated after a full CLOCK pulse period.
– If a limit switch is activated right from the beginning, then the controller attempts
to seek a position within the ± Tol range of the current position, initially opposite to
the defined direction, with the limit switch deactivated. If this does not bring
success, then the attempt terminates. In this case, the SWITCH status bit remains set
(see get_stepper_status).
– If a limit switch gets activated during a movement, then the reference run stops
there. Afterward, the limit switch position is crossed 4× to arrive at an averaged
value for this position. Finally, the stepper motor is driven in the opposite direction
by a normal set-position movement (Init status reset, Busy status set) within the
tolerance value Tol . Here, the DIRECTION status signal changes, whereas it remains
constant during seeking movements with multiple direction changes. The internal
position variable (for the current position) gets set to the value defined by the Pos
parameter. Thus, this value represents a positional offset by Tol with respect to the
defined position. With Pos = Tol , the middle limit switch position corresponds to
position 0.
– If no limit switch is found (for example, because no limit switch exists in the defined
direction), then the stepper motor performs an infinite movement. stepper_init
then returns after WaitTime seconds to restore system control to the user program.
But the stepper motor’s infinite movement continues until it is aborted by a new
stepper_init command or stepper_control( Period1/Period2 = 0). For more on
this, see the Section ”Terminating Infinite Movements”, page 286.
• If Period = 0, Dir < 0 and/or WaitTime = 0, then stepper_init returns straight away to
immediately restore system control to the user program. You can then call
get_stepper_status to check whether the reference run has completed. During the
seeking movement the status “Init” (see page 430) is set and during the terminating
set-position movement to (limit switch + Tol ) the status “Busy” (see page 430) is set.
• Period = 0 and/or Dir < 0 can be used as an emergency stop. Then a previously started
stepper motor movement gets aborted, but no reference run is performed. Here, too,
the position variable gets set to the value Pos . The DIRECTION signal remains
unchanged.
• If Period = 0, then status “Init” (see page 430) and status “Busy” (see page 430) get
reset. No further clock pulses are outputted until Period is again set to a positive value.
Ctrl Command stepper_init