Knowledge Base

Category: SurvCE / SurvCE 2.50
Topic ID: 768
Title: Leica Prism Constants
Created: 0000-00-00Last modified: 0000-00-00

In SurvCE Version 2.55 and higher we have changed the "P.C. mm applied" values in the RW5 raw file for Leica instruments in regards to the prism constants we record to the raw file.

We no longer show the customized Leica value of adding 34.4 to the physical prism constant in our RW5 raw file entries however we still calculate this value to send to the instrument before the measurements are taken in SurvCE.

In SurvCE 2.55 and higher our new entries in the SurvCE RW5 raw file for Leica instruments are displaying the physical prism constants so if you are using a Leica 360 prism we will record it as shown below: 
"--P.C. mm Applied: -11.3000 (Leica 360:foresight)"

The new record shows three values where I'll refer to the Sample above:
the physical prism offset (i.e. -11.3)
the Prism Name in paranthesis (i.e. Leica 360)
a note indicating if its a Foresight or Backsight (i.e. Foresight)

Using SurvCE 2.52 and older with a Leica 360 prism would generate the old record of:
"--P.C. mm Applied: 23.1"

Both of these records would still be setting your Leica Instrument to the correct variable internally of "23.1" on the actual instrument values used to create the Slope Distance.   We are still sending the same instrument commands but just recording them different in the RW5 raw file.

We needed to change Leica entries over to physical constants to provide consistency for someone who may start a job with Leica then switch to a Nikon, Sokkia or Topcon instrument so we don’t have a “Leica 4.4” value in the top of the rw5 raw and then a “Topcon -30” showing further down.   By always reporting physical prism constant values we are able to standardize the Leica prism entries with all other makes and models of total station.

If you would like to see the prism offset value that is sent to the Instrument you can go into Equip tab / Total Station / "Settings" tab then tap the "wrenches" icon to the right of the "FS Target" or "BS Target".

This screen will show the physical "Offset (mm)" but it will also display the "Leica adjusted offset" being sent to the gun in the bottom left as shown in the screenshot below:

Here is some more samples in our SurvCE Version 2.55 and higher:
--P.C. mm Applied: -34.4000 (Leica Circle:backsight)

--P.C. mm Applied: -11.3000 (Leica 360:foresight)

--P.C. mm Applied: -16.9000 (Leica Mini:foresight)

--P.C. mm Applied: 0.0000 (Leica 0mm:foresight)

--P.C. mm Applied: 0.0000 (Reflectorless:foresight)

--P.C. mm Applied: -30.0000 (-30mm:foresight)