Sequencer procedure

   # at start of the sequencer
   [connect()]    -> for all items: get and open a port object to communicate with a device
   [initialize()]  -> for all items: set all value and configurations to make the device ready for a measurement
   
   
       # if a Root-To-Leaf is started
       [configure()]   -> changes the configuration of the device
       [poweron()]     -> switches the device on
   
           # if a leaf of a Root-To-Leaf is reached
           [start()]       -> for all items of the Root-To-Leaf: prepare something before value is applied
           [apply()]       -> for all items of the Root-To-Leaf: set the new value to a device if supported 
           [sleephold()]  -> for all items of the Root-To-Leaf: sleep the hold time while the value is applied to the device
           [trigger()]     -> for all items of the Root-To-Leaf: make device ready to be triggered
           [measure()]     -> for all items of the Root-To-Leaf: initiate the measurement or send a trigger
           call()        -> for all items of the Root-To-Leaf: read the results from the port buffer
           [process()]     -> for all items of the Root-To-Leaf: use the chance to postprocess your data
           [finish()]     -> for all items of the Root-To-Leaf: clean up before the next measurement starts 
           [sleepstop()]   -> for all items of the Root-To-Leaf: sleep the stop time while the device is set to its idlevale
     
       # if a Root-To-Leaf is left
       [poweroff()]    -> for all items: switches the device off
       [unconfigure()] -> set value to idlevalue and apply() it
   
   # at end for all items of the sequencer
   [deinitialize()]-> for all items: reset the status for any other user of the equipment
   [disconnect()]  -> for all items: closes the port object