My Rangefinders TruPulse200X, Leica and Nikon

General discussions of measurement techniques and the results of testing of techniques and equipment.

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dbhguru
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Re: My Rangefinders TruPulse200X, Leica and Nikon

Post by dbhguru » Mon Dec 09, 2013 9:27 am

Karl, Doug, Don, et. al.,

The TruPulse 200 and 360 both suffer when there is foreground clutter. It doesn't matter if you have either instrument set to closest or farthest mode. Obviously, you want the farthest, but it does little good. Yesterday, I was rechecking the height of the Arvol Looking Horse tree in MTSF. I had gotten 159.1 feet previously. I had hoped to use only the TruPulse 360 this time, but couldn't successfully shoot through the clutter. I had to resort to the Nikon Prostaff 440 to get crown distances. I reduce the longest distance I record by a foot when using the 440 and that puts my in close agreement with the TruPulse. Well, I got exactly 159.0 this time. I'm content.

With respect to the TruPulses, the inclusion of the gate on the 200X is sorely needed. Thank goodness it is working. BTW, I think LTI used some of our input in designing the 200X. I can't say that for sure, but they put a lot of stock in our testing and development of solutions to tree-measuring problems. I hope they hear us about the reticle.

In checking the accuracy of a tilt sensor, I set up an indoor exercise. I have a leveling laser that I use to establish the point on the wall that is level with the instrument's centroid when on a tripod. I then measure vertical distances up and down the wall and mark them. I use a tape for this. I establish the slope distances from instrument's centroid to the wall when aimed at each target. I use my Bosch GM80 and verify with the Bosch GLR825, or vice versa. When I'm confident that the distances are correct from centroid to each mark on the wall, I then record the angle using the TruPulse to each mark on the wall. To be precise, I have to adjust baseline and vertical distances from the centroid due to head swivel of the tripod. I have formulas for that, but once I know the distances, I can solve for the vertical angle associated with those distances and compare to what the TruPulse shows. In doing these kinds of experiments, having an instrument like the Leica or Bosch to get accurate distances is essential. Oh yes, I check on the angle by doing two sets of measurements, one using arctan and the other arccosine. I do this because the vertical distances on the wall are obtained via a tape. This gives me an independent measure of vertical distance that I can use to check the corresponding one computed by the Pathagorean Theorem using the level distance to the wall and the slope distance to a mark on the wall as obtained using the Bosch. It is all a little convoluted, but gives me a pretty good feel for what I can expect from the TruPulse tilt sensor.

Bob
Robert T. Leverett
Co-founder, Native Native Tree Society
Co-founder and President
Friends of Mohawk Trail State Forest
Co-founder, National Cadre

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Karlheinz
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Re: My Rangefinders TruPulse200X, Leica and Nikon

Post by Karlheinz » Mon Dec 09, 2013 11:50 am

The problem with the wind and my Leica

The more precise the instrument focuses the beam, the greater becomes the problem with the wind. Even small, barely perceptible movement of air lets swing the top of a large conifer by decimeters. At a distance of 70 m the red laser beam of the Leica Disto is not larger than about 4 cm, which is of the same order as the width of the top shoot of a douglas fir. You can certainly imagine how quickly the beam disappears at the slightest movement of air in the empty background of the sky. And for a successful measurement the laser spot must have to remain on the top shoot for a few seconds. Thus it is clear that my Leica Disto is strongly affected by the wind problem.

For the measurement I strive to align the red laser point about the middle of the range of variation and then no longer alter its position (not touch the device). Then by timer I start a continuous measurement and the device then tries to detect measuring points. If several measuring points could be successfully detected, only that one with the maximum distance is displayed and stored. It may be that only after several minutes a first reading comes about, there you must have patience.

Unfortunately, for security reasons, the power of the red laser can not be increased. Will there be added further adverse conditions such as long distance or bright daylight, a measurement will quickly become impossible. Therefore, a point measurement to the top of a tall tree with the Leica often will require a great deal of time and effort and is not very practicable. I am glad that for this job now I have the TP200X.

Karl

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dbhguru
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Re: My Rangefinders TruPulse200X, Leica and Nikon

Post by dbhguru » Mon Dec 09, 2013 3:55 pm

Karl,

I just got notified by LTI that I can now place my order. There is a TruPulse 200X in my near future. Yeeehaaa!

Bob
Robert T. Leverett
Co-founder, Native Native Tree Society
Co-founder and President
Friends of Mohawk Trail State Forest
Co-founder, National Cadre

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Karlheinz
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Re: My Rangefinders TruPulse200X, Leica and Nikon

Post by Karlheinz » Tue Dec 10, 2013 4:15 am

Who takes the LTI price of the remote trigger cable for overpriced, or doesn't like the needless connector block dangling around at the end of the line, can buy the matching connector separately in electronics stores and combine with any button (eg the remote release of a camera). The LTI 4-Pin serial connector at the TruPulse is M8 Pico actuator/sensor from Lumberg Automation (Belden brand), compatible with Binder M8 Locking System
http://www.lumberg-automationusa.com/pr ... ur=2&term=
http://www.binder-usa.com/psearch#q=loc ... %20Locking

Karl
Last edited by Karlheinz on Thu Dec 26, 2013 3:56 am, edited 2 times in total.

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DonCBragg
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Re: My Rangefinders TruPulse200X, Leica and Nikon

Post by DonCBragg » Fri Dec 13, 2013 6:15 am

Karl--Thanks for the great report! I'd like to adapt this for the next Bulletin of the Eastern Native Tree Society, if possible--or if you'd like to update this original report with more information and field testing, that would be great, too...Please email me directly on this (DonCBragg@netscape.net).

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Karlheinz
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Re: My Rangefinders TruPulse200X, Leica and Nikon

Post by Karlheinz » Fri Dec 13, 2013 8:24 pm

Just I read in the manual of the new Leica Disto D810:

Maximum Measuring Tolerance ± 2.0 mm
Smallest unit displayed 0.1 mm

Can you imagine this accuracy?

Karl

Download the manual: http://www.leica-geosystems.com/en/Down ... pe=Manuals
D810-man-TechData.jpg

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