TM 5-6675-330-12&P
(e) When using the auxiliary cable, connect the
power cable to power connector (2). Connect the
red clip lead of the power cable to the positive
terminal of the 12 volt DC power source, and con-
nect the black clip lead to the negative terminal
of the DC power source.
(f) Setup the retro-reflector accurately over the
point to which the distance measurement is to be
made. Align the retro-reflector on the line of sight
to the instrument (see Figure 7). For maximum
signal return the retro-reflectors should be perpen-
dicular, with *5 degrees, to the instrument line-of-
sight.
Figure 7- Prism Alignment
2. Computing PPM Correction
[a) Take a temperature reading with the ther-
mometer placed in a shaded area and positioned
six to eight feet above ground surface. Record this
temperature reading.
(b) Take a barometric reading with the barometer
placed in a shaded area that is protected from
gusty wind conditions. Record this barometric
reading,
(c) Using the Atmospheric Correction Graph (See
Figure 8), Page 17, read the PPM Correction at the
intersection of lines extending from the measured
temperature and pressure, A one PPM variation will
cause a 1 millimeter per 1 kilometer distance
variation.
(d) Using PPM switches (43), dial the computed PPM
correction into the instrument.
NOTE:
The computed PPM correction can be either
positive or negative. Remember that the * section
of the PPM switch (43) will have to be set to one of
the positive or negative position for positive or
negative PPM corrections, respectively.
3. Offset Switch Setting
(a) Obtain the instrument total offset correction
(TOC) from the instrument offset plaque located at
the bottom front of the instrument. (Page 18].
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