Product Manual

3. THE MEASURING MECHANISM
Page 3
7
54 2
VERNIER
MEAS.
WHEEL
DIAL
MINOR MAJOR
DIVISION
DIVISION
(D)
(R)
(V)
Fig. 5
Read Dial, Measur-
ing Wheel and Ver-
nier in this order:
Dial = 2
M.Wheel (major)= 5
M.Wheel (minor) =4
Vernier =7
Result :
2547
HOW TO READ A MECHANICAL PLANIMETER
The reading of a mechanical planimeter, is
given on three different scales, as shown above. One of
these is a flat dial, "D"; the second, "R" is attached to the
measuring wheel; and the third is a stationary vernier
scale, "V", located immediately next to the scale, "R". The
disk provides the most significant digit, the scale at-
tached to the measuring wheel provides the next two
most significant digits, and the stationary vernier pro-
vides the least significant digit.
To get the reading, first look at the disk, "D". Notice a
small slotted-head screw that acts as pointer.
If this pointer points between two numbers, then take
the lower of the two as the most significant digit.
If it points precisely at a number, then this number is
the most significant digit provided that the next most
significant digit turns out to be either zero are almost
zero; otherwise the next lower number is the most sig-
nificant digit.
Next, look at the scale, "R", on the measuring wheel.
Notice that this scale has 10 major division markers
that are numbered 0 to 9, and 10 small divisions be-
tween each numbered marker. Also look at the station-
ary scale,"V", and notice that it has a single major
division marker labeled zero. This zero marker is the
pointer to be used to read the scale.
The measuring mechanism consists of a counting dial, a measuring wheel with
100 divisions, and a vernier. The counting capacity is 9999 .
When measuring large areas, it is important to closely watch the counting dial and
to add 10 000 to the readout for each complete turn of the dial.