New to the board, so thanks ahead of time for any comments or guidance. I'm an academic so don't spend every day in the field, but take classes out to survey often enough. Recently, I've been having a super frustrating problem with my Trimble S5 robot (TSC3 running Access). It keeps intermittently returning NO TARGET. The problem has come and gone over the last couple months and every time it occurs, I bring it back to the lab and setup inside and it works just fine. It seems to track the prism just fine, but at certain times will just not take a shot.
I was out with a class 2 weeks ago and it worked flawlessly. Went back to the same spot yesterday with another group, setup on the same 2 control points in the same exact way I would every time and I could not get a backsight. Tore everything down and set it all back up and same problem... NO TARGET on the bs. Made a new job and restarted everything and NO TARGET. Clear line of sight with zero obstructions. Looked down the scope and it was dead center on the prism.
This has happened both on setup and all of a sudden in the middle of work and it will not clear up. I've spoken multiple times to a technician at the vendor to no avail. I thought it might have been foggy optics combined with weather as the image in the scope was a bit fuzzy, so I packed it with silica gel desiccant in the case for a few days and the optics are crystal clear now but the problem persists. I just set it up inside once again and it works fine. I'm at my wits end as I just had it serviced not that long ago and they said it was super clean.
Does anybody have any clue what may be going on? How can it work just fine one day and be useless the next doing the exact same thing at the exact same site?!? Help!!!
Does anybody have any clue what may be going on? How can it work just fine one day and be useless the next doing the exact same thing at the exact same site?!?
What prism type? Traverse kit? MT1000? AT360? Do you use a different prism for your backsight than for your prism pole? Are you making sure that the right prism type/ID is selected when you go to start a new setup? Autolock on or off? Access will remember what was last used.
We have a Trimble Multi-Track prism. While I've played with changing channels, we only ever use channel 1 as we only have the one prism (and one Total Station). I did try changing channels in the field yesterday when it was failing, but no change. It would still track the diodes, just not "see" the prism on a shot.
also, I use autolock and active tracking. I'm losing my mind because I haven't changed any of the setup and one day it works, the next it doesn't.
The one thing that really knocks automatic targeting (both active and passive) is moisture in the air and condensation on the prism - but that is easily resolved with a soft cloth.
Next time it happens, try changing the prism setting to passive tracking.
If that works (it should) I would be suspicious of the active track diodes and circuitry in your prism.
You could also spin the prism 180degress to check it happens on all sides.
=J=
You said that looking thru the scope the cross hairs were dead on the prism so it is tracking and aiming but not measuring the distance. IMHO the problem is not the prism but rather whatever triggers the shot inside the gun. Next time it refuses to measure try taking a manual shot.
Also the gun may have taken a hard bump and knocked the EDM out of alignment with the cross hairs. If it will not measure in passive mode when aimed properly then manually (using tangent screws) move the scope around and see if you can get it to measure. If it measures when aimed way off the prism or maybe not at all no matter what, then you probably need an expensive repair job.
Edit: The fact that it will measure when the prism is up close (inside a room) then not measure when farther away (outside) actually is strong proof that the EDM is way out of alignment with the cross hairs.
I remember an issue many years ago. I think we could solve it sometimes by switching to DR mode (Direct Reflex, measuring without prism), and then back DR off and measuring with prism. Something with a filter involved. If I remember well we the instrument went to the shop for adjustments afterwards.
