[time-nuts] NTS-100 IRIG to GPS Conversion - (Was Tymserve 2100 -

Jim Palfreyman jim2 at tasmail.com
Wed Jan 10 18:36:43 EST 2007


Well I'm playing with the ACE III at the moment too. I have one driving my home built GPS based clock (I only use the 1 PPS in that) and I have another ACE III on the bench for fiddling and so I've been recently talking to it via its serial ports.

The default mode is TAIP on port 1. The actual pinouts of the ACE III are not clear in the ACE III technical manual - I had to email Trimble to get them. Let me know if you want them. (The pinout descriptions are in the manual just not which is pin 1 etc).

Don't forget the ACE III serial ports talk TTL and so your conversion cable will need to convert this to RS-232. I use the max232 chip. All it needs is a few 0.1 uF capacitors and a 5V supply. The default baud rate is 4800.

The 1PPS pin is a good indication if you've got a lock on a satellite. If you lose lock, the 1PPS continues for about 10 seconds and then stops. It's a 10uS pulse.

A cold start of the ACE III can take a number of minutes to lock.

Hope some of this may be of some use and I'd be interested in anyone's opinion or experiences of the ACE III.

Regards,

Jim


On Wednesday, January 10, 2007 at 05:03:27 PM, Discussion of precise time and frequency measurement wrote:

> Just a heads up for others that were interested in converting an NTS-100
> IRIG (or similar) to add a GPS...
> 
> I finally got in all the parts and attempted to assemble everything today...
> 
> Soldered the 2mm header to the NTS board (little pins are not fun)
> Mounted the ACE III (I think I need smaller diameter standoffs, but it works
> okay right now)
> Fixed the data cable (pin 1 was incorrect on the cable - had to check the
> ACE II manual to find out the proper pinout on the GPS board)
> Powered it up (nothing exploded)
> 
> The bootup took longer than usual before it showed the "IRIG Unlocked"
> screen, so I can only think that it was trying to communicate with the GPS.
> I'm about to call it a day, tomorrow I'll probe the TX/RX pins while it's
> powering up to see if it is sending anything.
> 
> I'm still hopeful, I think perhaps it is not in the right mode (TSIP),
> tomorrow I'm also going to make an interface cable so I can connect it to my
> computer and check / change that.
> 
> *keepin fingers crossed*
> 
> Jason
> 
> 
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