6 Programming
6.8.1. Programming recommendations
3HAC021272-001 Revision: H88
© Copyright 2004-2008 ABB. All rights reserved.
6.8 Programming recommendations
6.8.1. Programming recommendations
Declare syncident globally in task
By declaring all variables of the data type
syncident globally in the task program, there is
no risk of having two
syncident with the same name in the same task program.
Do not reuse syncident
A
syncident variable is used as an argument for all WaitSyncTask, SyncMoveOn and
SyncMoveOff instructions, so that the operator can distinguish which instructions are
executed simultaneously in the different task programs. If one
syncident variable would be
used as argument for more than one instruction per task, that instruction would no longer be
uniquely identified. To make sure your program code is understandable, never reuse a
syncident variable.
Declaring tools, work objects and payloads
Declaring a variable as
TASK PERS will make it persistent in the task program, but not shared
between tasks. By declaring tools, work objects and payloads as task persistent, you do not
have to keep track of whether the variable name is used in other tasks. If tools, work objects
and payloads are declared as
TASK PERS, the names do not have to be changed if the program
is copied or mirrored to another task.
A work object that is used by several task programs is preferably declared as
PERS. A tool
can be declared as
PERS if a background task needs to read the robot position.
Changing a PERS
A globally declared
PERS will keep its value even if a new declaration of the same PERS is
loaded. The value of the
PERS that was first loaded will be preserved as long as there is any
reference to that
PERS.
If you want to replace all the task programs with new programs where the values of the
PERS
is different, remove all task programs first and then load all the new task programs. That way
the old value of the
PERS will be lost when all declarations of it are removed.
Changing the value of a
PERS from the Data Variable view on the FlexPendant and saving
the program, will update the
PERS in a correct way.
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