[evlatests] Lost Command (?) problem

[Rick Perley]

    Yesterday I reported an instance in Michiel's holography script 
where it was clear that the antennas did not move as (he thinks) the 
script commanded. 

    Some have opined that the problem is within the script, and not a 
lost command. 

    A simple (but probably not sufficient) diagnostic is to repeat the 
script, and see if the problem repeated.  This was done this morning. 

    Answer:

    The problem did *not* repeat.  The antennas moved as directed.  
Careful examination of the full 121 raster points show that we did see a 
'non-moving' instance on any position. 

    At this point, it may be useful to succinctly restate the 
characteristics (and correct an error in my summary yesterday):

    1) For one commanded step, (and only one), the antennas did not 
move.  This applied to *all* antennas.  So all antennas stayed at the 
previous  position. 
    2) At the following step, all antennas went to the correct place, 
and have the correct angular coordinates.  My report yesterday stated 
that all subsequent positions had angular coordinates one step off.  
This was incorrect.  The only effect is that the 'missing' position has 
incorrect amplitude and phase.  All other positions are correct. 

    So, it looks like a 'lost command' to us.  Fortunately, this is a 
very rare problem.