RTC
®
5 PC Interface Board
Rev. 1.9 e
6 Developing User Applications
74
innovators for industry
6.4.4 Starting and Stopping Lists
List processing (“List 1” or “List 2”) can be started
either by the control command
or via an external start signal (see the
"Starting and Stopping Lists via External
Control Signals and Master/Slave Synchronization",
page 209
).
The command
can be used to start output of a list at a specified
address. If an external start signal is used (see the
section
"Starting and Stopping Lists via External
Control Signals and Master/Slave Synchronization",
page 209
), then the command
allows definition of a start address for
external starting of the list.
Output by the RTC
®
5 begins immediately. Even
during 10
µ
s-clocked execution of the list commands,
you can still send control commands to the RTC
®
5,
which will immediately execute them without
hindering execution of the list. This is useful, for
example, for loading a second list while the first list
is being processed (the PC and scan head then work
in parallel). But the second list can only be started
after the first list has finished processing. During list
processing,
commands and external
start signals are ignored.
Execution of a list can also be stopped at any time,
e.g. for implementing an emergency shutdown or for
any other purpose. Use of the
) will immediately abort the
currently running list and turn off (but not deac-
tivate) all “laser active” laser control signals. The
command can be used to cancel a
list execution automatically (as with
)
as well.
If, during list processing, the end of the list is reached
without encountering a
command,
then processing will continue at the beginning of the
list. This will be repeated until either the
command is called or
an external stop signal is transmitted to the RTC
®
5.
If, on the other hand, a
command is
encountered during list processing, then list
execution will stop
-
unless an
,
command was
previously issued. In the latter case, a list change will
take place (see
"Automatic List Changing", page 75
).
The change occurs only upon reaching a
command.
Notes
• Lists are not automatically started. Regardless of
how many commands are loaded, a list must be
started as described above in order to be
processed.
• To also enable starting and stopping of a list via
external signals, the RTC
®
5 provides corre-
sponding control inputs (see
Stopping Lists via External Control Signals and
Master/Slave Synchronization", page 209
).
6.4.5 Interrupting Lists for Synchro-
nization of Processing
The list 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
®
5 reaches a wait marker during list
execution (see
"Structured Programming", page 76
),
processing of the list is temporarily interrupted and
the laser is turned off.
The command
ascertains whether processing is currently inter-
rupted 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
The
command causes the PAUSED status
(queryable via
) to be set and the BUSY
status to be reset. The opposite occurs after a subse-
quent
command.
List execution can be interrupted at any desired point
in time via the control command
(or via
) and resumed via
command
causes the laser control signals to be disabled
(1)
and
keeps the scan system in the most recently defined
state – even if in the middle of microvectoring. After
a subsequent
command, the scan system
resumes the planned movements (of the current
command) and the laser control signals are reenabled
(1) If the signals are disabled, the laser output ports (LASERON,
LASER1 and LASER2) are in the (high impedance) tristate mode.
