Hi guys
I was out surveying a house and garden for an architect last week. I had to put a leg in so I shot to the prism on the tripod (the leg) but also shot to a mark I made on a building (an x mark from a black marker pen) using DR mode.
When I set up on the leg I used the mark on the building as a check shot. It was 12mm out from the previous shot!
I went back to the previous station to confirm the co-ordinates and yes from two different station setups I'm getting different co-ordinates for the check shot of up to 12mm.
Later on in the job I had to locate the outline of a neighbouring building. I used DR to do this. I wanted to shoot the external corner of the building. I know that in DR mode when shooting corners the shots sometimes "miss" the corner so before measuring the corner I shoot the object behind it to get an idea of the distance before I shoot the corner so I know when I get shorter distance they are in fact of the corner I want to measure and not the object behind.
Eg, the building behind the corner I want to measure is 100 meters away and the corner I want to measure is 15 metres away. I point the crosshairs at the corner and hit measure. If I get a distance of 100 meters I've missed the corner, if I get a distance of around 15 metres I know I've got the corner.
On this job I had to point the cross hairs around 10mm inside the corner in order that it didn't miss and measure the object behind it.
So is the DR on my TS Fu**ed?
My total station is a 3" Trimble S7.
Kind regards, Andrew
I believe you have a misaligned beam and by that I mean the narrow laser beam that is used to take the reflectorless (DR) shot is not aligned wit the crosshair.?ÿ Flip your total station's telescope 180 degrees and look 2 small plastic plugs on top. They cover the adjusting screws. Follow the instructions in your owner's manual to adjust the laser pointer using the supplied reflective target.?ÿ
I always take reflectorless shots in both faces, especially at long distances. This way any slight misalignment will be corrected by the average of the distances measured in face1 and 2. I hope this helps.
I have re aligned the beam in my leica several times.
I like setting it up about 100' from a target, that is a business card, with + on the back. Set the hairs on the +. Then adjust the beam around, until the intense part is centered on the +.
Ps, put card in a dark ish place. This helps make the beam plain on the card. Like under a covered porch.
- It's easy.
N
Thanks guys that's really helpful. So you aim at the target with the red laser on to see if its matching what the cross hairs are aiming at?
If you are concerned about the DR alignment, run the adjustment routine regularly for a couple of months, and if you are seeing it drift substantially take it in for service.
Also, I really like taking several reflectorless observations on the faces of the building to avoid problems with the EDM returning a bad distance. Much more precise and faster than trying to find a corner and getting a good return. Create best-fit lines in whatever CADD program you use, fillet them and you're done.
If the beam is poorly?ÿ aligned will the shots to prisms still be?ÿ okay??ÿ
?ÿ
Shots to prisms use a different beam, a wide beam and they should not be affected by the laser pointer's missalignment.
Years ago, I think Geodometer or Trimble had a routine that you shot two points on the building's face and then turned an angle to the corner and it would calc the point. I wish leica had that. It would solve a lot of trouble.
The DR appears to be measuring the correct distance, so I doubt the DR function itself is the issue.
Did you run the full calibration suite as outlined here? Without regular field adjustment, instruments can get way out of spec depending on the conditions they are subjected to. Some are worse than others; some just need to go back to the dealer and get sorted out occasionally.
Remember, S7 beam divergence is 2 cm horizontally at 50 m, and the DR Plus is a pulsed TOF measurement that effectively takes thousands of individual measurements and means them. If you have significant misalignment, a good chunk of that beam, and many of those measurements, might be observing something closer or farther than you are aiming at.
If a full adjustment doesn't improve the issue, get it in for service...
I think it is still there, the name of the routine just changed with one of the recent Access upgrades. Can't check for sure, I am currently in an office that uses Leica...
It used to be "Vertical Plane and Angle". Now it is "Measure Points on Plane", which gives you a bit more flexibility and will give you residuals when using the EDM.
If only I could get personnel at our Trimble-equipped offices to utilize these features. I get so sick of hearing about how "Leica sucks" or "Trimble can't do half the stuff that Leica can", and when I ask if they have tried these features I get a blank stare. From the allegedly "experienced" crew members.
Does anyone know what routine to run to adjust this on a Leica tcrp 1205? ?ÿI too have noticed the same issue with my robot. ?ÿI frequently run ??check and adjust? but don??t remember an adjustment for the red dot misaligned on crosshairs.
I believe that the alignment of the red dot and the crosshairs is an internal under the covers that can be easily fixed during a routine clean and adjustment at your favorite technician shop.
