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One of the first things to do with a new instrument is to test all the offsets. This should be done with each prism and all the various programs in the data collector. You don’t want the program to check into the prism on the backsite tripod and be set the same for the 360 prism or the tiny layout prism. Test, test, test, it’s simple to do.
Hello. Thanks for all the answers so far.
I know and understand what prism constant is and how to apply it.
What I don’t know and is confusing for me is the instrument offset written inside and if I have to apply it. For example if I use a Leica prism that has the real constant -34.4mm on a Pentax total station…I have to apply it in the instrument. Ok so far. But…
Do I ad or not the 20.2 mm ? In the Pentax software menu there’s not an option for something like this, only for prism constant.So.. Do I ad or not the 20.2 mm ?
This in the question ???
Set two points in your yard, the distance apart does not matter.
Pull out a steel tape and measure and/or setup an older TS and measure a distance.
Set you new gun on the instrument tripod and shoot the same and apply the resulting difference into your instrument until when you take a measurement it will be the same as your other TS or taped distance.
Bottom line – if you use Leica, use Leica prims. Anything else, I just set to 0, in instrument, DC, and prisms, and no worries.
Al Harris is exactly correct, test the actual distances, it will become obvious what you need to do. This isn’t really complicated. Measure it!!! All you need is a tape measure.
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