User Manual

Total Station Manual
206
3.8 Instrument additive constant (K)
The instrument constant is inspected when it out, and correct it inside the
machine, make K = 0. Instrument constant change rarely, but we suggest that check it
this way for one or two times each year. The checkout should be done in the standard
baseline, or you can take the following simple method.
 Checkout

Choose a flat field A to set up and level the instrument , mark three points A
ǃ
B
ǃ
C in the same line ,their interval is 50m, and set up the reflection prism
accurately.

After setting the temperature and pressure data, accurately measure the horizontal
distance of AB

AC.

Setting up and centering the instruments accurately, measure the horizontal
distance of BC accurately.

You can get the instrument ranging constant:
K = AC-(AB + BC)
K should be close to 0, if | K | > 5 mm, it should be send to standard baseline field
for strict checking, then calibrate it based on the checking value.
 Calibration
If it turns out the instrument constant does not close to 0 but changing after strict
inspection, you need to calibrate it, set the instrument additive constant according to
the comprehensive constant K value. Such as: the K has been measured as -5
according to the method above, and the original instrument constant is -20,so the new
value should be set as -20-(5) =-15; Input-15 through "menu-> 6-> 3" and then
confirm .
¾ Use the vertical line of the reticle to orientate, make A, B and C at the same line
accurately. There must be a clear mark for point B the ground to focus on.
¾ Whether the prism center of B coincide with the instrument centers is the
guarantee of checking the accuracy, so, you had better use tripod and all-purpose
tribrach, for example, if you change the three hand type prism connector with
tribrach, keep the tripod and tribrach stable, just change the prism and thepart
above tribrach of instrument, and it can reduce the error of misalignment.
3.9 The parallelism of collimation axis and photoelectricity axis
 Checkout

Set up the reflecting prism 50 meters long from the instrument.

Focus on the reflecting prism center with telescope crosshair accurately.

Open EDM signal, observe maximum value of the signal, and find the center of