[time-nuts] 58503A alarm light on, but :SYSTEM:STATUS? indicates all is ok

Bob Camp kb8tq at n1k.org
Wed Apr 1 17:48:23 EDT 2015


HI

Best guess is that your antenna is not doing the job. 

If the HP is in lock long enough to predict a good holdover (there are multiple limits) you can have
holdover with no alarm. If it goes into holdover and is not “ok” by the various limits, you will get an 
alarm + holdover. After being in holdover for a while (how long depends) you will get an alarm. Likely
values are in the 24 hour range if it’s been on for a while. 

There are many other ways to get an alarm light. The best way to figure out what they all are is 
probably a reverse-compile on the firmware in the unit. Since you have multiple errors showing 
in the log, they would be a good thing to start with. 

Bob

> On Apr 1, 2015, at 5:05 AM, Dr. David Kirkby (Kirkby Microwave Ltd) <drkirkby at kirkbymicrowave.co.uk> wrote:
> 
> Yesterday (31st March 2015) the "GPS lock" light of my 58503A went out
> and the "Holdover" light came on. The Alarm LED was *not* on. It had
> been like this for an hour or more. I removed the N connector, could
> see there was 5V DC on the antenna, and a visual inspection of the
> antenna cable did not give me any cause for concerns.  I decided to
> power cycle it. Anyway, it came back up, quickly achieved lock, and
> I'd rather hoped it was just a glitch, and that was the end of it. NO
> SUCH LUCK!
> 
> Today I notice the GPS lock light is on, Holdover is off, but the
> alarm LED is on. This is quite a different set of LEDs to yesterday.
> 
> This time I connected the GPS receiver to a computer, to try to find
> out what was up, and are confused in that the status appears to be ok,
> yet the alarm is on. The log does not indicate why the alarm light
> should be on. (I have had it come on before, immediately after power
> up, when it indicated the power supplies were out of regulation,
> although I've never managed to observe this on a peak holding DVM, so
> I am not convinced the power supply was the cause.) But the unit has
> been stable for quite a while, yet the alarm is on, but nothing in the
> log indicates a problem.
> 
> scpi > :SYSTEM:STATUS?
> ------------------------------- Receiver Status -------------------------------
> 
> SYNCHRONIZATION ............................................. [ Outputs Valid ]
> SmartClock Mode ___________________________   Reference Outputs _______________
>>> Locked to GPS                              TFOM     3             FFOM     0
>   Recovery                                   1PPS TI +5.0 ns relative to GPS
>   Holdover                                   HOLD THR 1.000 us
>   Power-up                                   Holdover Uncertainty ____________
>                                              Predict  4.9 us/initial 24 hrs
> 
> ACQUISITION ................................................ [ GPS 1PPS Valid ]
> Tracking: 6 ____   Not Tracking: 4 ________   Time ____________________________
> PRN  El  Az   SS   PRN  El  Az                UTC      08:19:28     01 Apr 2015
>  2  46 281   69     5  17 294                GPS 1PPS Synchronized to UTC
>  6  45 207   56    16  14  58                ANT DLY  0 ns
>  7  50 150   59    23  33  68                Position ________________________
>  9  65  67   75    30  25 177                MODE     Hold
> 10  81 277   63
> 20  58 289   62                              LAT      N  51:39:04.143
>                                              LON      E   0:46:36.402
> ELEV MASK 10 deg                              HGT               +47.15 m  (MSL)
> HEALTH MONITOR ......................................................... [ OK ]
> Self Test: OK    Int Pwr: OK   Oven Pwr: OK   OCXO: OK   EFC: OK   GPS Rcv: OK
> 
> 
> The "HEALTH MONITOR" seems to say it is ok, but the alarm LED is on.
> Querying the alarm LED, does indicate it is on.
> 
> scpi > :LED:ALARM?
> 1
> 
> So I decided to check the current date and time (which seem
> "reasonable"), and the log.
> 
> scpi > :PTIME:DATE?
> +2015,+4,+1
> scpi > :PTIME:TIME?
> +8,+59,+52
> scpi >  :DIAG:LOG:READ:ALL?
> Log status: 106 entries
> 
> Log 001:20141215.00:00:00:  Log cleared
> Log 002:20141215.00:00:00:  System preset
> Log 003:20141215.00:01:41:  GPS reference valid at 20141215.18:27:04
> Log 004:20141215.18:28:12:  GPS lock started
> Log 005:20141215.20:26:57:  Position hold mode started
> Log 006:20141218.00:00:00:  Power on
> Log 007:20141218.00:03:57:  GPS reference valid at 20141218.23:25:08
> Log 008:20141218.23:30:09:  GPS lock started
> Log 009:20141219.01:24:46:  Position hold mode started
> Log 010:20141227.00:00:00:  Power on
> Log 011:20141227.00:08:16:  GPS reference valid at 20141227.19:23:09
> Log 012:20141227.19:24:17:  GPS lock started
> Log 013:20141227.21:23:19:  Position hold mode started
> Log 014:20141229.00:00:00:  Power on
> Log 015:20141229.00:04:13:  GPS reference valid at 20141230.19:54:39
> Log 016:20141230.19:58:58:  GPS lock started
> Log 017:20141230.21:54:54:  Position hold mode started
> Log 018:20150101.00:00:00:  Power on
> Log 019:20150101.00:00:00:  Power on
> Log 020:20150101.00:00:00:  Power on
> Log 021:20150101.00:00:11:  5V is out of tolerance, value: 5.52
> Log 022:20150101.00:00:11:  15V is out of tolerance, value: 19.46
> Log 023:20150101.00:00:00:  Power on
> Log 024:20150101.00:04:09:  GPS reference valid at 20150101.11:38:39
> Log 025:20150101.11:39:46:  GPS lock started
> Log 026:20150101.13:30:40:  GPS reference valid at 20150101.13:30:39
> Log 027:20150101.13:31:47:  GPS lock started
> Log 028:20150101.13:39:40:  Position hold mode started
> Log 029:20150101.00:00:00:  Power on
> Log 030:20150101.00:00:55:  Power on
> Log 031:20150101.00:00:55:  Power on
> Log 032:20150101.00:00:00:  Power on
> Log 033:20150101.00:00:00:  Power on
> Log 034:20150101.00:00:08:  Power on
> Log 035:20150101.00:00:09:  Power on
> Log 036:20150101.00:00:16:  Power on
> Log 037:20150101.00:00:27:  Power on
> Log 038:20150101.00:00:30:  Power on
> Log 039:20150101.00:00:47:  Power on
> Log 040:20150101.00:00:53:  Power on
> Log 041:20150101.00:00:00:  Power on
> Log 042:20150101.00:00:07:  Power on
> Log 043:20150101.00:00:00:  Power on
> Log 044:20150101.00:00:11:  Power on
> Log 045:20150101.00:00:00:  Power on
> Log 046:20150101.00:00:00:  Power on
> Log 047:20150101.00:00:00:  Power on
> Log 048:20150101.00:00:00:  Power on
> Log 049:20150101.00:00:04:  Power on
> Log 050:20150101.00:00:09:  Power on
> Log 051:20150101.00:00:13:  Power on
> Log 052:20150101.00:00:20:  Power on
> Log 053:20150101.00:00:00:  Power on
> Log 054:20150101.00:00:00:  Power on
> Log 055:20150101.00:00:00:  Power on
> Log 056:20150101.00:00:00:  Power on
> Log 057:20150101.00:00:00:  Power on
> Log 058:20150101.00:00:19:  Power on
> Log 059:20150101.00:00:28:  Power on
> Log 060:20150101.00:00:32:  Power on
> Log 061:20150101.00:00:39:  Power on
> Log 062:20150101.00:00:00:  Power on
> Log 063:20150101.00:00:05:  Power on
> Log 064:20150101.00:01:34:  Power on
> Log 065:20150101.00:00:00:  Power on
> Log 066:20150101.00:00:00:  Power on
> Log 067:20150101.00:00:11:  5V is out of tolerance, value: 5.52
> Log 068:20150101.00:00:11:  15V is out of tolerance, value: 19.46
> Log 069:20150101.00:00:00:  Power on
> Log 070:20150101.00:03:51:  GPS reference valid at 20150101.20:01:38
> Log 071:20150101.20:02:45:  GPS lock started
> Log 072:20150101.22:01:35:  Position hold mode started
> Log 073:20150103.00:00:00:  Power on
> Log 074:20150103.00:00:00:  Power on
> Log 075:20150103.00:00:00:  Power on
> Log 076:20150103.00:05:29:  GPS reference valid at 20150103.15:56:09
> Log 077:20150103.15:57:17:  GPS lock started
> Log 078:20150103.17:57:19:  Position hold mode started
> Log 079:20150109.17:46:10:  Power on
> Log 080:20150109.17:50:58:  GPS reference valid at 20150109.17:51:02
> Log 081:20150109.17:52:10:  GPS lock started
> Log 082:20150109.18:13:01:  Power on
> Log 083:20150109.18:14:03:  Power on
> Log 084:20150109.00:00:00:  Power on
> Log 085:20150109.00:04:16:  GPS reference valid at 20150109.18:43:08
> Log 086:20150109.18:44:16:  GPS lock started
> Log 087:20150109.20:42:37:  Position hold mode started
> Log 088:20150311.00:00:00:  Power on
> Log 089:20150311.00:08:00:  GPS reference valid at 20150311.13:23:08
> Log 090:20150311.13:24:16:  GPS lock started
> Log 091:20150311.15:22:37:  Position hold mode started
> Log 092:20150330.19:30:37:  Holdover started, not tracking GPS
> Log 093:20150330.20:11:35:  GPS lock started
> Log 094:20150330.21:44:00:  Holdover started, not tracking GPS
> Log 095:20150330.21:46:18:  GPS lock started
> Log 096:20150331.12:18:13:  Holdover started, not tracking GPS
> Log 097:20150331.12:32:41:  GPS lock started
> Log 098:20150331.12:42:42:  Holdover started, not tracking GPS
> Log 099:20150331.12:47:30:  GPS lock started
> Log 100:20150331.13:41:30:  Holdover started, not tracking GPS
> Log 101:20150331.14:21:58:  GPS lock started
> Log 102:20150331.14:35:23:  Holdover started, GPS
> Log 103:20150331.00:00:00:  Power on
> Log 104:20150331.00:08:19:  GPS reference valid at 20150331.15:02:08
> Log 105:20150331.15:03:16:  GPS lock started
> Log 106:20150331.17:01:37:  Position hold mode started
> 
> I'm not sure why there were a bunch of "Power on" entries (029-066),
> but some of the log entries (e.g. 061 to 066) do not appear to be in
> chronological order. Other more recent "Power on" entries could be due
> to mains failure, as this is not on a UPS, and I know there have been
> some power outages. I was not aware of any outages yesterday - if they
> were, they were too short to cause any computers to reboot.
> 
> Any suggestions what I can do to try to find why the alarm would be on?
> 
> Once the LED is on, do they ever go out? I assume its purpose is to
> indicate there was a problem, rather than that there's currently a
> problem, but I'm puzzled there's no entry in the log to indicate why
> the alarm is on
> 
> Dr. David Kirkby Ph.D CEng MIET
> Kirkby Microwave Ltd
> Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Essex, CM3 6DT, UK.
> Registered in England and Wales, company number 08914892.
> http://www.kirkbymicrowave.co.uk/
> Tel: 07910 441670 / +44 7910 441670 (0900 to 2100 GMT only please)
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