No! Tripod/Total Station setup procedures
> Having the optical plummet in the instrument actually has its advantages...
My issue is with putting the instrument on the tripod before the feet are set and having it there while the feet are getting stamped on and various gross adjustments are in progress.
No! Tripod/Total Station setup procedures
> My issue is with putting the instrument on the tripod before the feet are set and having it there while the feet are getting stamped on and various gross adjustments are in progress.
So, why wouldn't a person stamp the feet as I do before mounting the instrument? Just eyeballing plumb over the ground mark through the hollow 5/8 x 11 screw on the tripod head will get close enough so that no repositioning of the tripod is needed.
No! Tripod/Total Station setup procedures
> So, why wouldn't a person stamp the feet as I do before mounting the instrument? ....
Not saying it can't be done. I'm not attempting to forbid you from doing what ever you think best. I work with crews who aren't always as experienced as you or as motivated to care for the stuff. Therefore, I build procedures that will work under the prevailing conditions for users at all levels of skill, care, and attention.
When it's me, I set the tribrach first and then put the instrument on the already levelled and centered tribrach. Why not?
No! Tripod/Total Station setup procedures
> > So the question is: Do you or do you let your crews adjust the length of one tripod leg at a time with the instrument in place?
> Well, um, No, actually. I don't. That is, I don't forbid it, but it shouldn't be happening.
>
> Because I prefer that they set up the legs with the TRIBRACH ONLY on the legs. Once the legs are levelled up and centered with the tribrach, then and only then the instrument comes out of the box and is placed on the tribrach, and locked in place. Proceed with fine tuning, which should not involve messing with the length of the legs at that point.
Aloha, Mark:
After making this basic inquiry couple years ago here...this is the method I follow now. I am happy with it and getting efficient...
Mahalo.
One more casualty...
One more casualty of the new business model. While I understand having solo crews with Robots and GPS, it diminishes the ability to train and mentor new Surveyors. Some of our 'rite of passage' experience probably had more to do with the anger issues of the Chief than becoming a good Surveyor. I may even have perpetrated a bit of that. Even so I have a constant nagging sense that things aren't quite right when I see some of the up and coming 'Crew Chiefs' these days. Not quite a sense of dread but very close. Back to the subject at hand...
As for the legs, my early experience was angle based. We only set on control when testing the declination of the instrument. Our error budget was kill radius minus a meter. After a short transition to civilian surveying I fell in love with adjustable legs. Letting a newbie slip them with the gun on would make me nervous, but I wouldn't insult another grey hair not allowing them to set up as they see fit.
As always, it depends...
No! Tripod/Total Station setup procedures
> When it's me, I set the tribrach first and then put the instrument on the already levelled and centered tribrach. Why not?
If one is traversing by forced centering and doesn't have a specific tribrach matched to an instrument, I suppose there wouldn't be any particular reason not to just grab a tribrach and use it to set up the tripod, particularly if it has a rotatable optical plummet.
One advantage to fine centering the instrument via the plummet in the instrument is that the plummet can be rotated 180 degrees to check its adjustment at every station and to significantly improve centering. Probably the more important advantage in the case of a tribrach that is matched to an instrument is that you don't have to remove and refit the tribrach to that instrument to carry it in the case from station to station, which is just awkward.
I did assume that the procedures you describe are adapted to a particular quality of field staff, but I would not have thought you were in the group.
No! Tripod/Total Station setup procedures
> Agreed, that is better if you have the option. Some instruments (like the ones I saw in use) have the plummet in the instrument and not in the tribrach.
Aloha, Bill:
My instrument's plummet is built-in. However, I have a Topcon tribrach with optical plummet that allows me see through it from the TS' plummet. It is kind of cool. I calibrated the Topcon tribrach with the TS's digital level bubble. I think, I may have minimized my centering error with this setup. But I'll let Kent verify that! 😀
Aloha,
No! Tripod/Total Station setup procedures
> I did assume that the procedures you describe are adapted to a particular quality of field staff, but I would not have thought you were in the group.
I do that way a) as an example for the crews (nothing kills standard procedure rules faster than having the boss excuse himself from them), b) because I think it puts less wear and tear on the instrument, and c) because that is what I'm accustomed to.
Yes, we have multiple tribrachs and tripods in each truck.
Phrase of the week
> ... Our error budget was kill radius minus a meter....
I do it that way except sometimes I re-center the plummet with the foot screws between 4 & 5 to get a more centered instrument on the tripod head especially if it's a steep, difficult or high mark setup.
Also it helps to to center the foot screws before starting.
No! Tripod/Total Station setup procedures
I prefer to setup with a tribrach first too then put the instrument on there.
When we traverse there is already a tripod centered over the point when I get to the next point.
> I do it that way except sometimes I re-center the plummet with the foot screws between 4 & 5 to get a more centered instrument on the tripod head especially if it's a steep, difficult or high mark setup.
>
> Also it helps to to center the foot screws before starting.
SOP should be to return the foot screws to the center position before returning the instrument to the case. I'm sure that an exhaustive description of how to set up a theodolite or total station would run to over three pages if every contingency were properly accounted for.
>return the foot screws to the center position before returning the instrument to the case
My practice, also. But the professor has them turning them all to the fully-down position. No idea why.
Send TDD over there, he will learn them to set up in under 5 seconds....:-P
That's exactly my method as well.
I am reminded of a state inspector back in about 1978 who was going to show me he knew how to set up a transit using a plumb bob. We were using an old Lietz transit that had a threaded bottom plate that screwed over a threaded tripod. I had been running it for a couple of years and got pretty good at it. This inspector was quite a bit shorter than me, and we were setting up at a centerline intersection on new road construction. The grade was red creek gravel. Transit was on the tripod with the scope with a sunshade pointed up and when he went to stomp one of the legs in it slipped off a rock and the scope flopped over and hit him right on top of his bald head. Then he let me set it up.
I have never understood all the dancing around looking through the OP with a leg or two in the air. At age 13 I began setting up my Dad's old transit on the standard fixed leg tripod and using a plumb bob. After a few years we graduated to a total station (semi-total station I think) with an OP and adjustable tripod. I couldn't figure out why the stupid thing only had three leveling screws. I tried for quite a few hours and even read the Japanese/English manual that only made it worse. One of Dad's friends stopped by and showed me ONE time. After that I was on my own. That's been 30+ years ago. Now I don't even think about what I'm doing when I set it up. It puzzles me that others can't just set the tripod over the point, step on the feet and maybe adjust one or two legs slightly, then set the instrument on the tripod ready to be fine centered and levelled. Even though I don't run the gun anywhere near enough to even be called a part time I-man anymore, I typically set it up faster and more accurately than the most experienced I-man in the company. I guess it became second nature from so many years. The method I use is a hybrid that does NOT jar the gun, is fast and easy (to me anyway). It seems the newer guys just will not learn without the gun screwed onto the tripod. It makes me cringe as I expect a foot to slip off a rock and jar the gun out of calibration. I guess no one these days takes an instrument/tripod home or skips lunch to learn how or speed up their technique.
Me. "What's the difference?"
T.C. Carroll "It's the difference between right and wrong!"
> It puzzles me that others can't just set the tripod over the point, step on the feet and maybe adjust one or two legs slightly, then set the instrument on the tripod ready to be fine centered and levelled.
> The method I use is a hybrid that does NOT jar the gun, is fast and easy (to me anyway).
Yes, absolutely. You stamp in the tripod legs BEFORE mounting the instrument and after that the adjustments are quite minor if even moderate care was taken.
Tripod/Total Station setup procedures
I've used that method for years.
Optical plummet in instrument.
If ground is anything but soft dirt I never stand on legs with instrument attached.
Any adjustments to legs is followed with a 'tweak' of the legs at the clamp area just in case the legs are clamped tight but not quite centred / snug in their circular grooved lower section.
I discovered it's easy to clamp tight only to find a slight movement and it then creeps slightly or at worst slips.
Generally I find it is easy to setup, clamp instrument on, level and make slight adjustment only on head.
I practised that for ages and it does come to you and well worth the effort and perseverance.
>So the question is: Do you or do you let your crews adjust the length of one tripod leg at a time with the instrument in place?
Yep. Sometimes even synchronised leg adjusting; two legs, two people at a time. That would make one person I know get a bit hot under the collar, but that gives it a mild sense of excitement. As much excitement as one can have when setting up a tripod that is.
Tripod/Total Station setup procedures
My tuition on setting up the tripod amounted to: 'Senter with the Screws, Level with the Legs'.