[time-nuts] Trimble/Nortel GPSTM (NTGS50AA) - working with Lady Heather.

bg at lysator.liu.se bg at lysator.liu.se
Sun May 20 21:49:41 UTC 2012


Sam, Mark, Murray and others,

Which pins on the large "CPCI" connector holds the RS422 serial port.
Power is on row 1 and 4.

--

   Björn

> There was some discussion in Dec 2011 regarding the Trimble/Nortel GPSTM
> (NTGS50AA) which fizzed out after it was mentioned that Lady Heather would
> not work with these units. I was undeterred and purchased some anyway.
>
> I have started playing around with these and have discovered that by
> asking it Sat status (0x10, 0x3C, 0x10, 0x03) at ~300ms intervals the unit
> will start streaming data after a few seconds. Once the Trimble is in this
> state Lady Heather detects the GPSDO and seems to work normally... Except
> the TC and DAMP fields which are reported as 0.0 and GAIN which is
> reported as -3.500 Hz/V (Tboltmon reports the correct values) I have read
> that this also happens with older Thunderbolts?
>
> I have written a small Windows app (available on request, off list) that
> sends the required packets to the GPSTM and by wrapping it in a batch file
> I have it opening Lady Heather once the unit is in the required state.
> (Only required once, or after running Tboltmon)
>
>
> Details of my 3, Trimble NTGS50AA's are:
>
> Firmware:
> App: 2.68  - 16 Dec 2004
> GPS: 10.4 - 15 Dec 2004
>
> GPS receiver has 8 Channels.
>
> Default disciplining parameters as reported by Tboltmon:
> Time Constant (sec): 100.0
> Damping: 1.2
> Ko (Hz/V) 1.20
> Min Voltage: 0.0
> Max Voltage: 6.0
> Initial DAC Voltage: 3.000000
> Jam Sync Thresh (ns): 0.0
> Max Freq Offset (ppb): 45.0
>
> These GPSDO's uses the Trimble 34310 DOCXO which I think is the Vectron
> OC-050?
>
> There are 4 SMB RF connectors on the main board:
> 1. GPS Antenna Input
> 2. 10.000 MHz Output
> 3. 9.834 MHz Output
> 4. 0.5 Hz (Even Sec)  PP2S Output. Unfortunately requesting the unit to
> output 1PPS does nothing. (yet)
>
> The 9.8304MHz output may be handy.. divided by 300 it's 32.768 KHz ;)
>
> Power Supply:
> The NTGS50AA requires 36-75 VDC (48V nominal) and has a on-board Lucent
> DC-DC converter to supply the required +/-12 and +5 volts.
>
> Serial Interfaces:
> Port A is RS-422 @19200 SCPI (available on the 110 pin connector on the
> main board)
> Port B is RS-232 @9600 TSIP (DB9 connector on Breakout board)
>
> LED indicators:
> There are 5 LED's on the breakout board that contains the DB9 connector.
> 1. Power
> 2. Not used, but switch-able via software
> 3. Not used, but switch-able via software
> 4. Lock
> 5. Holdover
>
> Temperature Sensor:
> DS1620 Rev D
>
> Jumpers:
> There is a 8 pin header (JP1) on the main board that would accept 4
> jumpers.. I haven't tried them but it is tempting to see what happens when
> I enable them.
>
>
> //Sam
>
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