[evlatests] antenna 13 out of service

[Rob Long]

Antenna 13 had the electricians working on the AC power problem for a 
good part of the afternoon.  While working, they must have dropped power 
to everything for awhile (including DC power).  The L305 was out of sync 
thus causing the DTS modules to have incorrect timing (19.2).  I reset 
everything (see the procedure described below) and told the operator 
that antenna 13 looked reasonable again.  The delays are probably still 
sad though.

To determine if the timing is good after a failure, the first thing to 
do is perform an L305 'sync_enable=1' (and after sync is good 
'sync_enable=0') to ensure timing is sync'd with the VLA.  If you then 
monitor the D30X 'Tic_period' you should read 0x196EXX (the last two 
digits will vary from module to module.)  If you do not read this value, 
the FPGA generating timing in the DTS module needs to be reset.  By 
performing a 'PscReset=1', the FPGA will reload as a result of the power 
reset and the 'Tic_period' should now read correctly.  The '8bit_Status' 
value should also read 0x5F (this indicates that the digitizers are off.)

Once the timing is correct, then the 'FormSwitch' can be turned on. 
While watching the deformatter statistics for the appropriate levels, 
verify that 'FOR_Pwr0', 'FOR_Pwr1', and 'FOR_Pwr2' are in the 900 range 
(slightly less or usually greater) and that 'DFM_PErr0', 'DFM_PErr1', 
'DFM_PErr2' are all equal to 0.  If any of these points are incorrect, 
try performing a 'FormReset' on the D30X.  Sometimes it takes more than 
one reset to get the correct values.

Once the deformatter values look good, turn the D30X '8bitSwitch' on, 
check the D30X '8bit_Status' to read '0xC0', and verify rms levels in 
the deformatter.  Occasionally, the 'FormReset' will have to be set 
again to achieve the proper levels.

Whenever I feel that I need to perform a 'PscReset', I shut down the 
'8bitSwitch' and then the 'FormSwitch'.  This procedure has served me 
well for quite a while and seems to be the safest way to reset a D30X 
module (DTS).

Rob

Ken Sowinski wrote:
> The power work at antenna 13 this afternoon left all
> the DTS modules unsynchronized with tic_period having
> a small integer value.  The only way I know to recover
> from this is to cycle power at the module.  I tried
> resetting both the formatter and sampler to no avail.
> 
> I have asked the operator to park the antenna and condsider
> it unusable until repaired.  If anyone is able to repair
> it the operator should be informed.  Even then it is likely
> to need help with delays.
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