Detailed Instructions for Using the Auto-Scale Factor
Although the Scalex Plan Wheel has a number of built-in scale factors,
it can also be used when the scale factor is not shown on the drawing
or may be incorrect. This feature is called the "auto-scale" and
is represented on the display by a wheel symbol. The auto-scale is
useful for plans which may have been reduced or enlarged, or on maps.
To use the auto-scale, at least one distance must be identified on
the print. For blueprints, use the largest distance which is indicated
anywhere on the print. On a map, use the bar which shows distance
or mileage. It is usually located toward one edge of the map. For
the greatest accuracy, roll the entire length of the bar.
The procedure for setting the auto-scale is simple after you do it
once or twice. Follow these detailed step-by-step instructions until
you get the hang of it. (If you get stuck, start over at number 1)
1. Press CLEAR.
2. If you are not already reading in the units you want (MI, FT, KM,
etc.), press UNITS until you get to the proper units. (Note - If
you cannot find the correct units, see note 5 below)
3. If you are not already on the auto-scale (wheel symbol), press
SCALE repeatedly until the wheel symbol shows. (Do not hold the button
just press it and release it - repeat until you get to the flashing
4. Once you have the wheel symbol (flashing or not), press and hold
SCALE for two seconds. If you have done everything correctly to this
you will see a row of seven zeroes across the top of the display with
the left-most zero flashing.
5. Carefully roll the wheel over the known distance.
6. Enter the distance you rolled onto the display. Do this by using
the blue left and right arrows to move the flashing digit (left arrow
= ADDER and right arrow = SCALE) and by using the blue up and down
arrows to increase or decrease the digit (up arrow = SQ/CU and down
arrow = SENSE).
Example: To enter 180 (starting with all zeroes, the left one flashing),
Right arrow (SCALE) - moves the flashing to the second digit (hundreds).
Up Arrow (SQ/CU) - sets the distance to 100.
Right arrow (SCALE) - moves the flashing to the third digit (tens).
Down arrow (SENSE) twice - sets the distance to 180.
7. When the distance
is correct, press the blue circle (UNITS). The auto-scale should now
be set correctly. Verify this by rolling over
the known distance again and checking to see that you get the correct
1. You may roll the known distance and enter the corresponding number
in either order.
2. The auto-scale will stay set even if you go to a different scale
factor, then come back to the wheel symbol. It will also stay set
if the scaler
turns off. (If you change the batteries, however, the auto-scale will
3. The actual scale factor will not be displayed. Only the wheel symbol
is displayed. If you wish to see the actual scale factor, you may
roll the scaler a real distance of one meter and read the length in
meters on the Plan Wheel's display. (Or you may roll the scaler a
real distance of one foot and read the length in feet.) Notice that
the scale factor may include a decimal fraction.
Example: If you roll a real distance of 10 cm and enter the distance
as 20 m, the scale factor will be calculated inside the scaler as
20 / 0.10 = 200. Then, if you roll the scaler over a distance of one
meter, the length will display as (approximately) 200 m, indicating
a scale factor of 1:200.
4. If, when you are entering the auto-scale, you realize that you
have made a mistake, push the CLEAR key to cancel. This will return
Plan Wheel to normal operation. Whatever scale was in the auto-scale
previously will still be valid. Then you may start over.
5. The Plan Wheel can be set to read in U.S. standard units (MI, YDS,
FT, IN) only, or in metric units (CM, M, and KM) only, or in both
U.S. standard and metric units. When selecting the units of readout
before setting the auto-scale, if you cannot find the correct units,
do the following: Hold down CLEAR and, at the same time, press UNITS.
Repeat until you find the correct set of units. Then let up CLEAR.
(For more information, refer to the instructions that came with the
6. If you are measuring from a nautical map, you can use statute miles
(MI) instead of nautical miles. Since you enter the known distance
in nautical miles, it will read back in nautical miles. (However,
if you switch to another readout, such as yards, the conversion will
not be correct.