When you lock onto an RMT how steady should the lock be? I see on the data collector that the HA moves around by one second or so. Is this normal? The ZA moves around by a tenth of a second. My SLR and 360 prism seem to lock on well, but I have one RMT(not a SLR) that won't hold lock at all. I have been able to get the tracker collimation to work on the instrument using the faceplate but not the TDS data collector. Any comments welcomed
I do know that the tracking is affected by heat waves. The cross hairs will "follow" the image.
thanks Digger. I am aware of heat waves, while the heat waves appear to cause the image in the scope to shimmer, the instrument tracks the signal emitted from the RMT diode. Setting the PPMs takes care of the issue. I did take my instrument into the shop today because I could not get the tracker collimation function to work....
I only use the 360å¡ RMT and noticed that when sighting it across 350' of hot asphalt, the horiz. angles changed in a manner that matched the shimmering heat waves. When a breeze blew the heat away, the horizontal angles were much more stable. I am guessing that the diode signal was affected by the heat waves?
Well there are two parts to the question. What is the impact of heat on the diode signal? What is the impact of heat on the laser to and the return from the prism? Hot air is where the laser will travel faster....
I THINK we are on the same page...two completely different measurements.
Horizontal angle - utilizes a diode signal. Signal appears to be influenced by heat waves, but is not subject to PPM corrections.
Slope distance - Utilizes beam of light and is subject to PPM corrections.
The EDM temp and pressure corrections won't help you deal with refraction.
There is no solution to shimmer except take shorter sights or return when conditions are better
That goes for diode tracking the same as ATR or optical observations
Its all just light waves.
I think you may have unrealistic expectations if you are worried about 1 second fluctuations in the readings
Dane Mince, post: 391916, member: 296 wrote: thanks Digger. I am aware of heat waves, while the heat waves appear to cause the image in the scope to shimmer, the instrument tracks the signal emitted from the RMT diode. Setting the PPMs takes care of the issue. I did take my instrument into the shop today because I could not get the tracker collimation function to work....
The din standard for this instrument is 3" per pointing so no I am not worried about 1 second. I have to admit that I was not paying close attention and so not being actually sure how the instrument is supposed to work, I was concerned when the HA display cycled through 1,2,3, 5, 8 seconds when the instrument was locked onto the target.... I went to the shop today and the tracker collimation worked perfectly. Soooo the only thing I can think of is that the environment when I was trying to run the tracker collimation routine had an impact on the instrument and caused the tracker collimation to fail. I was under an over pass and measuring under the San Francisco bay bridge(lots of steels). I was running the test at 700 feet, so curvature and refraction ought not be much of an issue
as far as I know the laser return is slower in wet cold air that it is in hot dry air , so I gather it is important to have these values set correctly in the instrument. I have seen shimmer at long distances on cold days as well....
Yes refraction / shimmer could be significant at this distance in a poor environment. Underneath a bridge sounds like the kind of place you might get significant effects from an unusual temperature gradient.
squowse, post: 392151, member: 7109 wrote: Yes refraction / shimmer could be significant at this distance in a poor environment. Underneath a bridge sounds like the kind of place you might get significant effects from an unusual temperature gradient.
Thanks Squowse perhaps I am mis remembering this and the distance where C&R are not an issue is 400 feet or less. I work mainly in San Francisco and the temperatures are very moderate and we rarely have day hooter than 80 degrees. My issue was not being able to run the collimation test successfully and temperature was not at issue
Dane, there is a distance/zenith angle you should meet in order to measure the tilt axis errors. I have to use a radio tower in order to get far enough away and still have a steep angle. I wonder if your angle was not steep enough for the routine?
The 5600 informs you when you run the when you are not close to 90 degrees when you run the optical collimation (within 5 degrees, I think) and within 15 gons, 13.5 seconds of zenith or nadir for trunion collimation. The software fails if you are not within these criteria and you cannot proceed with the collimation.....I had no problem with running either the optical or trunion collimation. My problem was with electronic being whacky and preventing the tracker collimation from working properly. For now I chalk it up to environmental adversely affecting the RMT diode signal....The other situation could be that the problem is intermittent .... Time will tell Thanks Dugger
I know many people are caught off guard when the gun doesn't sight the middle of the prism after running the tracker collimation routine.
Numerous times I have had tracker problems on sunny days when there were large tin barn roofs in the background. Even when the barns were 1/4 mile beyond the target. So it is possible for it to be affected from environmental conditions.
Dane,
I read your post the other day and it just now struck me. I see a recurring reference to a laser in the conversation that I thought was about tracking an RMT. I don't think that is Kosher.
Does the 5600 use the laser for RMT measurement? I had been told that this was not the case. I hope it does so at a much reduced power level that reflector-less.
JA, PLS SoCal
the 5600 uses a laser to measure distance..The diode for the RMT is used to track the prism....If the tracker is not collimated properly then the measurement may be subject to errors in distance and angle....or as Digger has pointed out there are environmental issues that may degrade the signal from the diode which would render the measurement unreliable.
The 5600 would only use a laser to measure if it is in DR mode. *reflectorless".
400 feet or less should give no refraction problems under normal favourable conditions. It all depends on the conditions.
In Britain we are mostly blessed with perfect surveying weather. Overcast.
nope sorry distance is measured via a laser diode, not just the reflector less measurements . At least that is what the 5600 users' manual states.... Class 1 laser...
Dane,
Please, recheck that manual. There are two measurement systems in the 5600, IR and laser. I was warned very early on, with whatever version of that instrument that I was using that attempting DR (laser) measurements to a prism would cause problems.
A word to the wise.
JA. PLS SoCal
WTF, this entire thread i have never been talking about reflector-less measurements. I have attached a copy here. It clearly states that distance measurements are made using a class 1 laser.... "A LED for the distance measuring function operating at 850nm (infrared, nonvisible light), with a beam divergence of 1.6 mrad and an output power of <0.44mW, laser CLASS 1." BTW I DO NOT SUGGEST THAT YOU TAKE A REFLECTOR-LESS SHOT ON A PRISM...