Omron SYSMAC CX-Programmer 8.1, Руководство по эксплуатации

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Elements of SFC Section 2-3
53
Step 2
N Action 1
N bFlag
Indicator Variable
AQ
Action Name
Indicator Variable
• An action block is inserted into a single step.
• There is no limit on the number of actions registered with an action block.
Administering Action Blocks
When a step becomes active, all actions in its action block are executed according to
the conditions set by the action qualifier.
While a step is in the active status, each action in its action block is executed once
each cycle. During a cycle, action blocks are executed in sequence, from top to bottom,
when Boolean bits are specified. With action programs, the programs are executed in
sequence after execution of the Boolean bit actions, and the sequence is from top to
bottom, in the order that they appear in the project workspace.
Action Qualifier (AQ)
AQ defines the execution timing for each action.
It can determine how the actions should be executed when the step becomes active.
Only one AQ can be specified for each action.
The action’s type determines whether the outputs are held or reset when the step goes
from active to inactive status. When necessary, change the initial settings or add reset
processing to the program.
•
When a bit is specified, the output is reset when a holding action qualifier (S) is
not specified. The output status is held if a holding action qualifier is specified.
•
With ladder programs, the outputs are reset by default. The default setting can
be changed to hold the output’s status.
• With ST programs, the status of the outputs in the program is held by default.
When necessary, write reset processing in the program and use the Action
Flag (a flag that goes ON when the corresponding step in an ST program
becomes inactive) to control the reset processing.
Note: For details, refer to 1-5-1 Holding or Resetting an Action’s Outputs .
Types of Action Qualifiers (AQs)
There are 11 AQ types, as follows. D, DS, L, SD, and SL have a time element.
For functions and for time element availability of the 11 AQ types, refer to the following
table.
AQ List
AQ
Symbol
Name Function Timer Set
Required?
D Delay The action is executed after the user-specified time has
passed, since step activation. If the step becomes inactive
before the user-specified time expires, the action will not be
executed. Yes
DS Delay SET Carries out the same operation as "SD". In contrast to “SD”,
the action will not be performed if the step becomes inactive
before the user-specified delay time expires. To cancel the
execution, use the “R” AQ. Yes
L Limit When the step becomes active, the action is executed until
the user-specified time expires. Should the step become
inactive, execution of the action will be terminated. Yes
N Normal
(Default)
The action is executed for as long as the step is active.