Product Manual

6. PREPARATIONS
6.1 TRACER ARM LENGTH
SHORT ARM
Shorten the tracer arm as much as
possible. (run the stop pin against the body)
Fig.8
loosen clamp screw
Before you start your measurements
with a model 30 you need to optimize
your instrument by choosing the tracer
arm extension most suitable for your ap-
pli- cation.
Owners of model series 10 and 20 in-
struments have no choice, since the
tracer arm length is fixed.
The readout results of mechanical plani-
meters are expressed in planimeter
units and they need to be processed in
order to obtain true area values.
Therefore it is necessary to prepare a
special measuring constant (C
A
) to com-
pensate for a scale ratio or to select the
appropriate "u" value for 1:1 measure-
ments.
SERIES 10/20 PLANIMETERS
have a fixed resolution and range, limiting the
use of the instrument to some extend.
SERIES 30 PLANIMETERS
give you the choice to configure the instrument
for maximum accuracy by selecting a short
tracer arm extension or for maximum measur-
ing range by selecting a long arm. In addition it
is possible to use a compromise setting (me-
dium arm).
Furthermore, all model 30 planimeters are
calibrated to provide 1:1 measurements di-
rectly in inch
2
and cm
2
by using a precalibrated
arm setting. (check next page)
IMPORTANT:
For maximum precision always use the short-
est arm length possible. This is especially im-
portant, if the areas to be measured are
smaller than 1 in
2
/ 6 cm
2
.
If the size of the area makes it necessary to
subdivide it for evaluation, then you should use
a long arm which permits measurements in
one (or as few as possible) continuous tracing
operations.
Model 30 Planimeter Tracer Arm Extensions
can be quickly changed as shown on the left
side of this page.
Tracer arm settings for 1:1 inch and 1:1 cm re-
sults are shown in your calibration records.
How to adjust the tracer arm length to these
values is shown on page 6.
Push the arm into the planimeter body
until it is flush with the body.
loosen clamp screw
LONG ARM
Fig.6
MEDIUM ARM
loosen clamp screw
Set the tracer arm to 16 (the graduation
line 16 must be aligned with the index line 0)
Fig.7
Page 5