Sequencer: ideas about implementation

[seb5g]

This is a draft to discuss about how to implement a Sequencer. The idea is to provide a way to to perform a sequence scan. Such a sequence scan would be a succession of blocks of different nature, each of the following blocks repeated as many times as specified in the current block. Each block in a column would define a timeline of events/actions. Several columns could be specified to trigger parallel sequences with possibilities for synchronisation/wait for completion.

Such sequence blocks would be, but not only limited to:

• Timer: would repeat the following sequence at given times (if the following takes less time that the timeout time)
• Waiter: would wait a given time before going further
• actuator: this block would typically be an instance of the current scans as specified in the DAQScan but without detection
• detector: selection of several detectors that should snap data
• configurator: block allowing to change the configuration of several actuators and detectors (settings for both) and set value (move_abs) for actuators. A particular state of a configurator could be "configured" elsewhere and called here. Looks a bit like a genralized overshoot configuration. See Configurator: a genralization of the overshoot configuration #578 for a dedicated discussion
• optimizator: typically the result of the bayesian optimisation in order to reoptimize things. For instance executed in another timeline synchronized with moment where the actuator block proceed with the next position or between a timer a subsequent (actuator/detector) blocks ...
• other ideas?

Each block could be added in a timeline sequence several times, only once or none.

Some blocks could be set as blocking (wait for completion) or asynchrone (start an action and move to the next block without waiting for completion)

Each block should implement a saving mechanism for the overall sequence to be saved and loaded at need