User guide

Configuring an Application www.controltechniques.com 61
properly. Figure 83 shows an example of the Queue view.
Figure 83: Queues View
7.3.13.0.1 A detailed explanation of each of the queue
components is as follows:
7.3.13.0.2 Queue Data
The queue data is loaded into the queue by statements in
the user program. Two types of data are most often used
with the queue: Position Feedback, and Master Position
Feedback.
7.3.13.0.3 Number of Queue Units
This selects the number of Queues available. Maximum of
eight.
7.3.13.0.4 Name
You can assign a descriptive name to each queue, making
the setup easier to follow. The length of the text string is
limited by the column width with a maximum of 12
characters.
Simply double click on the Name field of any queue to
assign a name to it.
7.3.13.0.5 Queue Size
This is the maximum number of elements that can be
stored in the queue. If more than this number of pieces of
data is in the queue at a time, then a Queue Overflow
source will activate.
7.3.13.0.6 Full Level
The amount of data in the queue is constantly monitored
and the Queue Full source will activate when the number
of pieces of data in the queue exceeds the Full Level
parameter.
Queue Full is only a flag and does not cause an error or a
trip of any kind.
7.3.13.0.7 Queue Offset
The Queue Offset is the value that is added to the Queue
Data and then compared to the selected source to
determine when the Queue Exit event activates. For
instance, if the source in selected source is set to
Feedback Position, and the Queue Offset is set to 10, and
the user puts the value 5 into the queue, the Queue Exit
source will activate when the Feedback Position is greater
than or equal to 5 + 10 or 15.
7.3.13.0.8 Source
The Source determines which parameter the sum of the
Queue Data and Queue Offset are compared to in order to
activate the Queue Exit function. If set to Position
Feedback, the sum of the data and offset are compared to
the Position Feedback parameter. If set to Master Position,
then the sum is compared to the Master Feedback Position
parameter, and if set to Command Position, then the sum
is compared to the Motor Commanded Position.
Queue Sources and Destinations
Figure 84 shows a block diagram of the Queue object.
Figure 84: Queue Block Diagram
Sources
Queue Exit - This source activates when the Comparator
Select parameter is greater to or equal to the sum of the
data entered into the queue, and the queue offset.
Queue Empty - This source is active if no data is stored in
the queue. It will become inactive when the first piece of
data is loaded into the queue and remain inactive until all
data has been removed from the queue.
Queue Full - The Queue Full source will activate if the
number of pieces of data in the queue equals or exceeds
the Full Level parameter. The source will deactivate when
the number of pieces of data in the queue is less than the
Full Level.
Queue Overflow - This source activates when there is no
Set # of Queue Objects = 0
and clear data in queue
D
ata In
Source Select:
MasterPosn
FeedbackPosn
CommandPosn
Comparitor
Sum
Q
ueueClear
C
ompareEnable
IF (# of Queue
Objects = 0)
QueueEmpty
QueueExit
Data Out
Queue
Size
Full
Level
IF (# of Queue
Objects = or > Full Level)
QueueFull
IF (# of Queue
Objects = Queue Size)
QueueOverflo
w
Queue Offset Exit Position