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XPS-Q8 Controller
11.0
Event Triggers
XPSDocumentation V1.4.x (EDH0301En1060 — 10/17)
XPS event triggers work similar to IF/THEN statements in programming. "If" the event
occurs, "then" an action is triggered. Programmers can trigger any action (from a list of
possible actions, see section 11.2) at any event (from a large list of possible events, see
section 11.1). It is also possible to trigger several actions with the same event.
Furthermore, it is possible to link several events to an event configuration. In this case,
all events must happen at the same time to trigger the action(s). It is comparable to a
logic AND between the different events.
Some events are one-time events like "motion start". They will trigger an action only
once when the event occurs. Some other events have a duration like "motion state".
They will trigger the same action each time (as applicable) as long as the event occurs.
For events with duration, the event can be also considered as a statement that is checked
whether it is true or not. A third event category are the permanent events "Always"
(always happens) and "Timer" (happens every nth servo cycle). They will trigger the
action always on every nth servo cycle.
As the XPS controller provides the utmost flexibility in programming event triggers, the
user must be careful and consider possible unwanted effects. Some events might have a
duration although only one single action is asked. Some other events might never occur.
This is especially true when linking several events to an event configuration. The
different possible effects are illustrated in section 11.3 by a few examples.
To trigger an action with an event, the event and the associated action must first be
configured using the functions EventExtendedConfigurationTriggerSet() and
EventExtendedConfigurationActionSet(). Then, the event trigger is activated using
the function EventExtendedStart(). When activated, the XPS controller checks for the
event at each servo cycle (or each profiler cycle for those events that are motion related)
and triggers the action when the event happens. Hence, the maximum latency between
the event and the action is equal to the servo cycle of 125 µs or equal to the profiler
cycle time of 400 µs. For events with duration, it means that the same action is triggered
at each servo cycle, i.e. every 125 µs, or at each profiler cycle, i.e. every 400 µs, as long
as the event is happening.
Event triggers (and their associated actions) are automatically removed after the event
configuration has happened at least once and is no longer true. The only exception is if
the event configuration contains any of the permanent events "Always" or "Timer". In
this case the event trigger will always stay active. With the function
EventExtendedRemove(), any event trigger can get removed.
The function EventExtendedWait() can be used to halt a process. It essentially blocks
the socket until the event occurs. Once the event occurs, it is deleted. It requires a
preceding function EventExtendedConfigurationTriggerSet() to define the event at
which the process continues.
The functions EventExtendedGet() and EventExtendedAllGet() return details of the
event and action configurations.
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Motion Tutorial
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