AUTOMATIC LEVELS
(DUMPY LEVELS)
Room with a view
M
agnification
has always been a troublesome point as the main factor to purchasing
. One question we often hear is "How far can I see?". How
far depends on how good your eyesight is for a particular sized
object at a certain distance. However, there is a rule of thumb which
we use. If you are within an acre of ground you are safe with an
automatic level with a magnification of 18x to 20x. Past that but no
more than a few hundred metres select a unit that is 22x to 26x
magnification. Over a few hundred metres or where accuracy becomes a
serious issue 28x or better is the only option. There are First order
levels and unless you know what first order means don't bother to ask
as the prices for these items are approximately USD$4,000 / AUD$8,000.
Did you bring your scuba gear?
Another issue is waterproof. The term for waterproof is rather a meaningless classification if no standard accompanies the statement. Survey manufacturers generally have their products between IPX4 and IPX6, where IPX7 (instrument can be submerged below 1 metre of water at its base) is the most "waterproof". Some products are nitrogen filled as a means of waterproofing. So, what IPX do you need? In a dry environment any level will suffice. Majority of Automatic Levels have a rating of IPX4 which as far as the manufacturer is concerned is sufficient for any condition that such levels have to endure. We have not seen a level better than IPX4 but some will tell you that nitrogen filled is the best waterproofing. Yes and no. Only the lens system is nitrogen filled whilst the compensator in all makes and models are not. The idea of nitrogen filled lens system is a concept specifically to eliminate fogging or moisture ingress in the lens system under any condition. Ideally in an extremely wet or humid environment this idea with a reasonably waterproofed compensator is the ultimate. However, costs to repair these items may only warrant purchasing in continuous usage in severe weather conditions. Levels of this nature are somewhat dearer than those without nitrogen filled lens system. Non nitrogen type levels work perfectly well in 90% of all applications. Sales have shown this to be the case.
She's breaking up Captain
Reliability. This is an issue that we find difficult as reliability doesn't just rest with the instrument. The case, or tools must be considered. The Survey manufacturing industry at the low end of equipment choices is very competitive and margins are very small, therefore, you get what you pay for. A typical example is a moulded joint rather than a metal hinged type for the two casing halves. The moulded type is where the top and bottom casing is joined by a thin pliable plastic strip. These are renowned for breaking in a matter of a few years where as the metal type will last 3 or 4 times as long. A lot of these issues depend on the use and abuse by the owner or the owner's staff. We have sold "cheap" instruments to people who only need it for one job and are not concerned about when the next oil change is needed or if the tyre tread is low. We have not replaced or credited a level under warranty as yet no matter how inexpensive. The only issue is customers wanting something clearly that is inadequate for their needs. We have never had a customer complain what they bought was more than they needed, but rather it was the best choice.
Mission impossible
If you are still not sure what you want, tell us that you are confused, tell us what you intend to use the instrument for and in what weather conditions it has to cope with, then we will give you advice within 24 hours. Good luck and may you complete your mission successfully.