Topcon QS3A TS with TopSURV8, angle errors

Topcon QS3A TS with TopSURV8, angle errors

Posted by TrueNorth on Apr 13, 2012 2:10 pm

Just started using the Robotic QS3A with the FC2500 data collector.  The data collector is setup with TopSURV8.  So far I have been very impressed with this setup as far as the robotics go.  However I have found that conventional traversing is not very user friendly.  When turning a set collection (BSD, FSD plunge FSR, BSR) the instrument will respond inconsistently.  By this I mean that without changing any settings or procedures the instrument will reverse by itself sometimes and also comes up with a +/-30" error (in horizontal only) sometimes.  I cannot duplicate the problem and it does it about 30% of the time.  It appears to be random.  The +/- 30" error occurs from direct to reverse and upon turning to the BS in reverse it shows +/- 180-00-30.  It is always a positive 30" when it does it.  This is very frustrating and takes additional time in the field repeating angle sets until you get a good one.  I recently closed a 8000' traverse with 0.13' of distance error and 40" for bearing closure. It took two and a half days in the field due to repeating the angle sets.  When it turns correctly it is very accurate.  This is not my first rodeo and I realize that having the correct temp and pressure is crucial. I also preform a "self check" of the compensator's daily along with a vertical culmination.  When preforming conventional work I have all "auto tracking" and "prism recognition" set to off.  During the traverse the weather was perfect (50-60ºF and overcast) and the instrument level was good at each setup.

It only happens with the following settings:
Measurement Mode:      Angle/Dist Sets-Dir/Rev
Angle Sequence:         BS/FS Plunge FS/BS

I did find that if I turn the sets as a side-shot (direct and reverse) there is no problems but the downfall is that it only considers the FS measurements. In other words it does not include a BS reverse measurement.

So....if anyone has had this problem or one similar please let me know.  Any advise would be appreciated.