RTC
®
4 PC Interface Board
Rev. 1.3 e
4 Principle Of Operation
14
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START Signal
Before the /START input can be used, it has to be
enabled with the command
. 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
Alternatively, the list command
To check whether a list was successfully started,
the command
can be used.
Notes
• An explicit call of the command
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
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no longer active.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
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
tains whether processing is currently interrupted at a
marker. If processing is interrupted, the command
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