User guide

60 www.controltechniques.com SM-EZMotion Module User Guide
CaptureActivate if the Capture component is enabled and
reset. Capture Triggered will remain active until
CaptureReset is activated.
Destinations
CaptureEnable - The CaptureEnable is used to enable or
"arm" the capture component. If the CaptureEnable is not
active, then the CaptureActivate has no effect, and the
CaptureTriggered remains inactive. Once the
CaptureEnable is activated, the Capture component is
ready and waiting for a CaptureActivate signal to capture
data. CaptureEnable is a read-only destination on the
Assignments view, and is accessible through a user
program.
CaptureActivate - If the Capture component is enable and
has been reset (CaptureTriggered is inactive), then the
rising edge of CaptureActivate will capture the four data
parameters and cause CaptureTriggered to be activated. If
the Capture component is not enabled, or has not been
reset, the CaptureActivate will be ignored.
CaptureReset - The CaptureReset is used to reset or
re-arm the capture component after it has been activated.
Once the capture has been activated, the
CaptureTriggered destination will be active. The capture
component cannot capture data again until it has been
reset. The capture component will automatically reset itself
if the CaptureEnable signal is removed.
Figure 82: Capture Timing Diagram
Figure 82 is a timing diagram that shows how the different
capture related sources and destinations function. The
three numbers located on the diagram are associated to
the following three notes respectively:
1. While CaptureTriggered is active, a rising
edge on CaptureActivate will be ignored. The
capture object can not activate again until it
has been reset.
2. When CaptureEnable is deactivated,
CaptureTriggered automatically deactivates
because the capture object is automatically
reset. The captured data is retained until the
capture component is re-enabled and
CaptureActivate is activated.
3. CaptureActivate has no effect while the
capture component is not enabled.
Sources That Can Accurately Capture Data
Only a select few sources can accurately capture data. The
reason that only certain signals can accurately capture
data is because they are wired directly to the SM-EZ
Motion FPGA or the signal is generated internally by the
processor and can be activated in the FPGA. Signals that
are not wired to the FPGA or sent to the FPGA can be used
to capture data, but it will only be accurate to the Trajectory
Update Rate. This means that the capture will only occur
the next time the signal is updated and not when it actually
activates.
Sources that CAN accurately capture data:
• SM-EZ Motion Inputs
• Motor Encoder Marker Channel
• Index.#.CommandComplete
• Jog.#.CommandComplete
• Index.#.AtVelocity
• Jog.0.AtVelocity
• PLS.#.Status
All other Sources are only accurate to the Trajectory
Update Rate.
Assignments that Automatically Use Position Capture
The sources listed above automatically capture data each
time they activate even when a capture object is not
configured. If any of these Sources are assigned to a
destination, the captured data may be used by the
destination function.
The Destinations that can use the automatically captured
data are as follows:
• Index.#.Initiate
• Index.#.SensorTrigger
The automatically captured data is not available to the user
like it is when a capture object is used. The processor takes
care of resetting the automatic capture internally.
Index.#.Initiate - When one of the Sources listed above
(Sources That Accurately Capture Data) is assigned to an
Index Initiate, the captured information is automatically
applied to the index starting point. This offers extremely
high accuracy for initiation of motion, which is beneficial
especially in synchronized applications.
Index.#.SensorTrigger - The sensor trigger destination
used in registration indexes can use captured data to
accurately calculate the ending position of the index based
on the Registration Offset parameter. The Offset distance
is added to the captured position to let the accurate
stopping position for the registration index.
7.3.13 Queues View
The Queues View allows the user to configure the
necessary parameters for the Queue object to function
CaptureEnable
CaptureActivate
CaptureTriggered
CaptureReset
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