[evlatests] problems parking evla antennas

[Ken Sowinski]

There are two reports below.  I do not know whether they
refer to the same event or are independent problems, but
read on ...

> From phicks at nrao.edu  Tue Feb 14 07:31:05 2006
> Return-Path: <phicks at nrao.edu>
> From: "Phillip D. Hicks" <phicks at nrao.edu>
> To: <dmidgett at nrao.edu>, <ms-evla-online-soft at aoc.nrao.edu>
> Subject: C117666
> Date: Tue, 14 Feb 2006 07:30:58 -0700
> 
> Work status on work order number C117666 is OPEN / AFFECTS DATA
> 
> Work Requested:  Report Only.  When a script is running on the Executor,
> the antenna PARK command doesn't work properly.  The PARK command is
> being overridden by the script commands.  Upon execution of the PARK
> command, the commaned position readings change to the appropriate parked
> values, but after a few seconds they revert back to the postions
> commanded by the script.  This is the case with antennas 13, 14, & 16.
> Occurred during file 499S859, L-band, line mode 4, BWC 1111.

Rightly or wrongly this is documented behavior.  The MIB
continues driving the ACU for five minutes after the last
pointing polynomial is sent by the executor and attempts to
park the antenna in this interval will fail.  This can be
addressed by 1) having the park command send positions with 
a new limit time and polynomial terms of zero, or 2) building
the park command into the MIB, or 3) using the brute-force stow
utility which overpowers other commanders of the antenna, or 4)
waiting for the limit time to expire vefore trying to park the
antenna.


Since the following, posted to evlatests only talks about 
antenna 14 I suppose that it is an independent problem.

> Last night, the operator was unable to park antenna 14 after an observe 
> script ended. Here is the sequence of events.
> 
> 1.  Script ended.
> 
> 2.  Operator attempted to park the antenna; acu display indicated 260/88.
> 
> 3.  After approximately 3 seconds, the display reverted to 427/36 and 
> the antenna continued to drive to that position. Elevation continued to 
> decrease.
> 
> 4.  The operator stopped the antenna by putting it into standby.
> 
> 5.  From the ACU screen, the operator set the az/el; the commands stayed 
> for approximately 3 seconds, then reverted to 519/65.
> 
> 6.  The operator attempted dpm, park, stow, direct acu commands; all to 
> no avail.

I must take the blame for this.  Walter and I were testing
his power level testing utility yesterday using antenna 14
and I left an executor running.  Since it was running a 
'sysstart' file it never finished and clearly caused what
was reported here.  

There is still the interesting question of why the antenna
could not be stowed.  Even with an executor running a stow
command from the ACU screen should cause the antenna to stow.
A test is warranted to be sure that the MIB changes last week
did not compromise the stow command.  I am also puzzled as to
why the positions given in items 3. and 5. are not the same;
perhaps one is a remenant position from the script that ended
and the other was from my errant executor.