Loading With Protection; Terminating Lists; List Status - Scanlab RTC 5 PC Interface Board Installation And Operation Manual

Loading with Protection

The loading process is initialized via the command
load_list, which sets the input pointer to the
specified address in the selected list (just like the
set_start_list_pos command), but only if the
selected list is not currently in use. Alternatively, you
can simply let the input pointer be set to a currently
non-active or already processed list via
®
RTC 5 will automatically determine the corre-
sponding appropriate list).
The return value of the load_list
and in which list, the loading procedure was success-
fully initialized. Otherwise, the input pointer will be
set to an invalid position, in which case no further list
commands can be input until the input pointer is
correctly set (e.g. by repeating the
command with a positive result or via the
set_start_list_pos command).
This automatically prevents unintentional over-
writing of not-yet-executed commands.
The load_list command is useful in scenarios such as
alternating list changes, where you want to wait
specifically for a list to be processed (see
List Changes", page 75).

Terminating Lists

Command lists can be, but need not necessarily be,
terminated via the set_end_of_list
However, if an unterminated command list is
executed and the output pointer thereby encounters
the last possible position in the list, the output
pointer will automatically reset to the start of the list
and processing will continue there. Automatic list
changing after a list is processed can only occur if the
set_end_of_list
list was terminated via the
(see "Automatic List Changing", page
The loading of a set_end_of_list
stop the loading procedure itself. Additional
commands in the same command list can be further
loaded directly after the set_end_of_list
®
RTC 5 PC Interface Board
Rev. 1.9 e
6 Developing User Applications

6.4.2 List Status

Dependent on the command input and output
statuses, lists can receive particular status values. To
examine the current statuses of the lists, the control
command
separately for both lists.
• A list's LOAD status (LOAD1 or LOAD2) indicates
load_list (the
• A list's READY status (READY1 or READY2) is set
command reveals if,
• A list's BUSY (BUSY1 or BUSY2) status indicates
load_list
"Alternating
• A list's USED status (USED1 or USED2) is set when
command.
Notes
• If the list status is queried during processing of a
command
75).
• If list execution is interrupted (via pause_list,
command will not
• If list execution is aborted (via
command.
• If you want to explicitly set the USED status for a
read_status (page 390)
that the input pointer is currently in this list. The
LOAD statuses of the other lists are then not set.
when the set_end_of_list command is written
during the loading procedure. It is reset when the
list's LOAD status is newly set.
that the output pointer is currently in this list
after list execution (of "List 1" or "List 2") was
started. The BUSY statuses of the other lists are
then not set. Execution of the
command causes a reset of the BUSY status (or
alternating setting, if automatic list changing was
previously activated). If a list is opened for
loading while still being processed, its BUSY
status will still remain set.
the set_end_of_list command is reached during
processing. It is reset when the list's LOAD status
is set.
subroutine in the protected buffer area ("List 3"),
then the status will be returned of the list ("List 1"
or "List 2") in which the output pointer most
recently resided (typically from where the
subroutine was originally called).
stop_list or set_wait), then the above-
mentioned status values will remain unchanged.
an external list stop), the USED status is set for
both lists (as via initialization). Also see
load_list(ListNo=3).
list ListNo (e.g. after abortion via
stop_execution or an external list stop), then
load a set_end_of_list command to a free
position Pos of this list via
can be used –
set_end_of_list
stop_execution or
72