[time-nuts] Upgrading TS2100 from TCXO to OCXO

[Robert Watzlavick]

Assuming your OCXO unit came from the vendor pre-configured that way, 
that means there are no changes required to the info field to convert it 
from a TCXO to OCXO, just the gain and filter setting.  This also seems 
to match what Greg Dowd mentioned yesterday.

My unit (TCXO/GPS originally) has the root/eng/timing/offset set to 
-100. A TCXO-IRIG unit that I looked at has an offset value of 0.  When 
I was first bringing up my unit with the OCXO, I was comparing the 10 
MHz output against a stabilized Thunderbolt and I noticed the TS2100 EFC 
voltage seemed to stabilize but there was an offset in the 10 MHz 
output.  The lock LED wasn't turning on either.  I got impatient and 
started poking around and that's when I noticed the "offset" parameter 
was set to -100.  I changed it to 0 and the lock LED immediately turned 
on but then the EFC started heading the other direction.  I put it back 
at -100, let it sit for a few hours, and it eventually locked without a 
frequency offset.  I'll set my offset back to 0 and see where it ends up 
overnight.

I believe the bc635PCI has a very similar timing engine and its manual 
has an entry for Command 0x29, Set/Request Advance/Retard Clock Value 
which may be a similar function.  The description says "This command 
sets the value of the advance/retard clock that is used to slew the 
timing the 1PPS epoch.  This command will allow the user to speed up, or 
slow down, the on-board oscillator while the TFP is in a flywheel state 
or Freewheel Mode.  The TFP adjusts up to 100 msec per second.  Each 
count is 10 us."  If it was the same timing engine, then you would think 
the units would be the same though.

-Bob

On 03/30/2011 04:19 PM, Jason Rabel wrote:
> To all:
>
> I ran the "root eng ee info" on my two TS2100s, both were originally IRIG units but I upgraded them myself to GPS models...
>
> Both my OCXO unit and TCXO unit reported "00000000"
>
> As for the parameters in my "timing / utils" directory, here's both models:
>
> OCXO (MTI 240-0530-D)
> ---------------------
> gain = -20
> filter = 0.9995000
> low = 0.0000000  (Manual says this isn't used, but figured I would post it)
> d/a = 0xa05d
> tfp 0 = 0xa005
> tfp 6&  7 = 0.9994965
>
>
>
> TCXO
> -------------------
> gain = 2
> filter = 0.9500000
> low = 0.0000000
> d/a = 0x85c0
> tfp 0 = 0x85a4
> tfp 6&  7 = 0.9499970
>
>
> My OCXO model came from Yahoo!, it still has the asset sticker on the side. It was in free-run mode when I got it. As mentioned
> above, the OCXO is a MTI with the following info:
>
> Model:  240-0530-D
> PN:     010285-0530
>
> If you want to see some hi-res images:
>
> http://www.rabel.org/archives/Images/TS2100/
>
>
> Time to poke around the eng directory and see if I can fix that pesky offset compared to my other time servers... There used to be a
> command in the earlier firmware versions but it appears they removed it.
>
> remote      refid  st t when poll reach   delay   offset  jitter
> ================================================================
> +NET4501-1  .GPS.   1 u   37   64   17    0.714   -0.029   0.087
> *NET4501-2  .GPS.   1 u    -   64   77    0.820   -0.022   0.129
> +PRAECIS    .GPS.   1 u   61   64   37    0.712    0.052   0.058
> -TS2100-1   .GPS.   1 u   63   64   37    4.937   -0.406   0.025
> -TS2100-2   .GPS.   1 u    -   64   77    4.976   -0.366   0.046
>
> The "root / eng / timing / offset" shows:
>
> Current offset : -5 at offset unit (100ns)
>
> I wonder if that might do the trick? Hmmm...
>
>
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