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--- getting_started:tutorials:sequencer4 [2018/06/28 09:55] – graf
+++ getting_started:tutorials:sequencer4 [2021/03/31 15:40] (current) – [Monitor Checking two Sequences] ursgraf
@@ Line 1: / Line 1: @@
-====== How to Organize Sequences and Steps ======
-<code cpp>
-class Readying : public Sequence {
-public:
-  Readying(std::string name, Sequencer& seq) : Sequence(name, seq) {setNonBlocking();}
-  int action() {
+====== Sequence with two Monitors ======
-    cs.setMaxSpeed(1.0);            // we assume that the control system offers some speed limitation
-    cs.pathPlanner.move(readyPos);  // we assume that the control system comprises of a path planner
-  }
-  bool checkExitCondition() {
-    bool end = cs->pathPlanner.endReached();
-    if (end) safetySystem->triggerEvent(safetyProperties->readyDone);
-    return end;
-  }
-};
-</code>
+In the EEROS library you will find a directory with examples. For this example see [[https://github.com/eeros-project/eeros-framework/blob/master/examples/sequencer/SequencerTest40.cpp|SequencerTest40.cpp]].
-<code cpp>
+Open a shell in the build directory of your EEROS library and run
-class Move : public Step {
+<code>
-  int action() {
+$ ./examples/sequencer/sequencerTest40
-    cs.setMaxSpeed(1.0);            // we assume that the control system offers some speed limitation
+</code>
-    cs.pathPlanner.move(readyPos);  // we assume that the control system comprises of a path planner
-  }
+This example shows a sequence with two associated monitors. The ''Main Sequence'' tries to run several steps called ''Step A''. After each step a counter is incremented. A monitor checks for this count to reach a given level (''MyMonitor''). As soon as this happens an exception sequence is started. After termination of the exception sequence the original sequence resumes because the monitor property is set to ''resume''. The ''Main Sequence'' continues and is soon interrupted by its timeout monitor because its timeout limit has expired. The timeout monitor has no exception sequence assigned to it and immediately aborts the ''Main Sequence'' and with it the application because its monitor property is set to //abort//.
+[{{ .:sequencerexample4.png?450 | //Two monitors checking the same sequence// }}]
-  bool checkExitCondition() {
+\\
-    return cs->pathPlanner.endReached();
-  }
-}
+==== Altering the Monitor Behavior ====
+Change the behavior of ''My Monitor'' to ''restart'', recompile, and observe what happens. After the exception sequence the ''Main Sequence'' restarts. This causes the counter to start with 0 and the timeout will be reset as well. Hence, the timeout monitor will never fire.\\
+If you change the behavior of the timeout monitor to ''restart'', things get more complicated. ''MyMonitor'' will fire, the exception sequence will run, the ''Main Sequence'' will resume, and the timeout monitor will fire. This monitor has no exception sequence but will simply restart the whole procedure.
+===== Monitor Checking two Sequences =====
+The next example is [[https://github.com/eeros-project/eeros-framework/blob/master/examples/sequencer/SequencerTest41.cpp|SequencerTest41.cpp]].
+Open a shell in the build directory of your EEROS library and run
+<code>
+$ ./examples/sequencer/sequencerTest41
+</code>
+This example shows a sequence with two associated monitors. The ''Main Sequence'' tries to run several steps called ''Step A''. After each step a counter is incremented. A monitor checks for this count to reach a given level (''MyMonitor''). As soon as this happens an exception sequence is started. After termination of the exception sequence the original sequence resumes because the monitor property is set to ''resume''. The ''Main Sequence'' continues and is soon interrupted by its timeout monitor because its timeout limit has expired. The timeout monitor also has an exception sequence assigned to it. After this the sequence continues because its monitor behavior is set to //resume// as well. Both monitors will fire again as their conditions are met again before the sequence finally terminates
+[{{ .:sequencerexample5.png?450 | //Two monitors with two exception sequences// }}]
+\\
-class Readying : public Sequence {
-public:
-  Readying(std::string name, Sequencer& seq) : Sequence(name, seq) {setNonBlocking();}
-  int action() {
-    move(readyPos);
-    safetySystem->triggerEvent(safetyProperties->readyDone);
-  }
-  bool checkExitCondition() {
-    bool end = cs->pathPlanner.endReached();
-    if (end) safetySystem->triggerEvent(safetyProperties->readyDone);
-    return end;
-  }
-};
-</code>