Scanlab RTC 4 - Synchronization of Processing

RTC
®
4 PC Interface Board
Rev. 1.3 e
4 Principle Of Operation
14
innovators for industry
START Signal
Before the /START input can be used, it has to be
enabled with the command set_control_mode (see
page 103). Subsequent START requests will start the
loaded list. The list will only be started by the external
START request if it is closed and no list is executing at
the moment.
The desired list can be selected via the command
select_list (page 102).
Alternatively, the list command set_extstartpos_list
(see page 105) can be used.
To check whether a list was successfully started,
the command get_startstop_info (see page 85)
can be used.
Notes
• An explicit call of the command stop_execution
disables the external /START input. An external
/STOP signal also (at least temporarily) disables
the external /start input, i.e. as long as the /STOP
input is LOW. The command set_control_mode
(see page 103) defines whether or not the /START
input also stays disabled when the /STOP signal is
no longer active.
• Please note that the /START input is edge sensitive
(HIGH to LOW level transition), whereas the /STOP
input is level sensitive.
Synchronization Of Processing
The command set_wait (see page 118) makes it
possible to set wait markers (break points) within a
list. Each marker is associated with a number greater
than zero.
When the RTC
®
4 reaches a wait marker, processing of
the list is temporarily interrupted and the laser is
turned off.
The command get_wait_status (see page 88) ascer-
tains whether processing is currently interrupted at a
marker. If processing is interrupted, the command
get_wait_status returns the number (wait_word) of
the corresponding marker. Otherwise the command
returns zero.
The wait markers are provided for synchronization
purposes. The application program should perform a
handling routine for each wait marker.
When that handling routine is finished, processing of
the list can be resumed via the control command
release_wait (see page 101).