|
How about the best tip ever. Throw the factory supplied rain hood as far as you can, and forget it! The last 25 years or so, our industry has evolved from optical-mechanical instruments to opto-mechanical-electronic designs. Now we all know that electricity and water do not mix; also, moisture and electronic circuit boards are a bad mix.
We work outdoors, it rains, its humid...a quick shower spings up, and all of a sudden your $10,000 total station is all wet. Certainly, the past 10 years most models are marketed as "weather resistant"...at one time some manufacturers offered "water proof" and actually dunked the instruments in a fish tank to prove it....one thing they left out was, you better not rotate it while under water. Anyway, most units are "resistant" whatever that means. However, common sense tells us that for longevity and less downtime: "dry is better".
Since we still get caught in a sudden downpour, the natural response is to cover the instrument with the factory supplied rain hood. Oh, those factory beancounters! Notice how the hood barely fits over your instrument...don't wanna spend too much on material costs. Typical practice is to remove the hood after the shower, fold it up and place it back in the case.
You see where this is going. Now the moisture is inside the hood, the hood is in the case, the case is sealed tight, and you've got a humidifier just attacking your instrument. We have seen rain hoods that actually have fungus and mold inside....just think what this does to your electronic components...not the first time, nor the first 20 times, but over a few years it is like rust on a car...slowly attacking, slowly adding a corrosive element that is not good for electronic instruments.
What to do? Glad you asked. Buy each truck a box of 20 or 30 gallon Hefty trash bags, place in glove box, use ONCE, and then take home for trash bag use. Hey, it goes on quick, covers half the tripod too, protecting it as well.
Since we're lecturing, may I suggest that your field crews KEEP THE CARRY CASE CLOSED at all times. There is a DIRECT correlation to instrument performance and longevity with the carry case interior cleanliness. Survey 101 says take the instrument out, close the case immediately...don't let rain, dust, grasses, twigs, rocks, sand etc in. Most cases have gaps between the fitted foam and hard shell; moisture gets in those crevices and takes forever to dry out. You wouldn't believe, or maybe you do, the condition we see inside cases that give us a very good clue as to the amount of service cost needed. The field crews need one hint: "our company makes "X" amount of profit, I, your friendly boss take most, the IRS takes more, what's left can go to you, or for repairs and service. Help us both, take a moment, and take care of our equipment."
Now why would I share this and limit my service work? Simple, most won't read this, and some that do won't implement it...so pay me now, or pay me later.
Quality angular readings and field results hinge on booking what you see. Almost all total stations offer 30X telescopes with 2 or 3 second resolution. This combination of magnification and resolution allows precise pointing of the telescope and good field shots.
As a 35+ year trained repairperson, I am constantly amazed to see instruments come in for service with eye lenses looking like picture #1
New, instruments have a clear, almost blueish-purpleish tint
Over time, ambient grease from fingers, eyeballs, eyelashes, combined with moisture and dust from field operations cause the eye lens to "cloud over". This absolutely impacts magnification and resolution....similar to looking through a smeared windshield in your car, or greasy eyeglasses. The result is a magnification deterioration from the 30X you paid for to 15X or even 10X, plus you can forget resolution, along with quality angular readings!
Take a moment and look at your instruments....go ahead...we'll wait.
See, I told you. Hey, forget the front lens (objective lens), it is a light gathering source, your eyeball is focussed on the reticle (crosshairs)....kinda like looking past the bugs on your windshield to the road ahead. Of course the front lens shouldn't be caked in mud, but dust, film etc is not that important....not near as important as your eye lens.
What to do? Simple, every now and then use some q-tips and windex to GENTLY clean your instrument eye lens. Squirt windex on your desk in a small puddle, dip q-tip in a SMALL amount, and in a gentle circular motion clean eye lens. If the lens has some grit on it, fluff up the first q-tip and gently brush off sand particles etc, then proceed to clean with windex.
One tip, by breathing on the eye lens, if clean, you should see the fog from your breath dissapate slowly. If still dirty, the areas will be obvious. At this time, you can take a soft cloth, and, using the windex GENTLY clean your front lens. Presto, you now have 30X optics and your field results are way better than your competitor who hasn't read this!
By the way, I recommend not using any front lens caps or covers. The least amount of tugging, twisting or pulling on that critical multi-lens component the better. Your infrared or pulsed beam is in critical optical-electrical alignment (i.e., the EDM goes where the crosshair is pointed). The stability and tighteness of that lens is very important.
Hey! Your welcome....your cleaning Invoice is in the mail.
Any automatic level can "stick" or "hang-up", causing errors in reading. All manufacturers recommend that the user take steps to assure proper compensator performance. Earlier models allowed check by "tapping" on tripod leg or tapping instrument telescope with two fingers, inducing oscillation of the compensator (user notes this by observing corsshairs during oscillation...crosshairs should move off line, oscillate up and down before settling on line "level").
Compensators can hang on damping mechanism, or on the stoppers (stoppers limit "swing" and protect wires under a shock); Lietz/Sokkia models eliminate any problems with hanging on the damping mechanism, as this brand uses rare earth magnets with large gaps to dampen oscillation...unfortunately, this prevents tapping on the tripod or instrument, as the damping effect is so strong. However, no brand can eliminate hanging on the stoppers.
Stopper hang up can come from dirt, grease or misalignment caused by bumps, blows, falls... or wear from transportation*. After years of use, we clean and realign stoppers, sometimes repointing the stops.
*Transportation issues: early models had a carry case design that held the instrument "vertically", i.e., the front lens facing toward 12 o'clock. Later models were held in case horizontally, front lens facing 3 or 9 o'clock. It is our opinion that during transport (non-use) the compensator is constantly swinging back and forth in horizontally carried instruments, causing wear and damage to stoppers, accelerating "hanging up" problems.
We recommend tranporting any automatic level in the vertical position.
Finally, it is good survey practice to always "test" compensator performance. In the Lietz/Sokkia models with heavey damping, we find the following procedure works best:
Observe crosshair after leveling up. Almost always one of the 3 leveling feet will be "in line" with the front lens (direction of observation). As you "burp" the 1 level footscrew, the user will observe the crosshair oscillate and then settle on level line. If it is hanging up, usually "burping" the one level screw will cause enough "shock" internally that the compensator will release from stopper. Also, gentle movement of the telescope from shot to shot can cause hanging, as side swing can "cock" compensator. A rougher motion is better, or a slight jerk will prevent cocking.
 Picture 1
Although photo #1 above shows an updated '80's Lietz/Sokkia design cutaway of their rare earth magnetic damped compensator, their very latest design incorporates an ingenius "stopper-limiter". Picture #2 below shows the current compensator with the pointer at this composite cage stopper-limiter. Picture #3 is a closer view of this cage.
So, what does this mean to you as a user? Almost all stoppers incorporate sharply pointed screws that make contact with a flat surface, effectively limiting travel....and we want to limit travel, in fact beware of instrument specs that tout a longer travel spec; 10 minutes is great, 8 would be better, over 12 is asking for trouble. In fact, when we overhaul and repoint compensators, we tighten up the travel to ensure precise arc swing and repeatability.
Back to sharply pointed screws: in use, and worse, in vehicle transportation, these stoppers are beating themselves up, flatening the points and making divots in the flat surfaces which in turn leads to a larger contact area in which ambient grease fumes and light dust accumulate, creating a perfect storm for "hanging up". Again, in service, we clean the sticky residue off, repoint screws, tighten up travel and bill you. The screws are softer after repeated repointing, and the divot remains, so it does not take too long to repeat the hanging up problem.
In our opinion, the unique Lietz/Sokkia cage, a composite material in which a "round" pin travels to and fro as the compensator seeks perpendicularity with the ground, effectively eliminates stopper sticking...just not much surface area, and a round pin vs. a sharp point...believe me this is the best design I have ever seen since I took service training at Lietz in 1978, and the thousands of levels we have serviced since 1973...and we have seen some ridiculous designs that are junk right out of the box!
Who cares? Who uses levels anymore? Well, all I know as a service facility, the darn grumpiness of the boss when his level has cost his company time, money and sometimes reputation. What to do? Well, transport the level with the objective (front) lens facing up (12 o'clock); testing operation by a variety of methods before booking that critical shot, and consider purchasing a design that works for you, not against you.
|
