SELF TEST ERROR.

To. TEST the stroboscope, proceed as follows:

a. Allow the instrument to warm up for about 10 minutes.

b. Refer to SELF TEST table in the instrument cover or to Table

2-1 for the HIGH CAL and LOW CAL RPM dial settings indicated for the

power -line frequency being used. Turn the range switch to the corres -

pending range required to make these settings.

c. Set the RPM dial to the exact HIGH CAL RPM dial setting called

for in the SELF TEST table.

d. Adjust the HIGH CAL screwdriver control until the on -off pattern

of the CAL neon indicator lamp stops, or nearly stops (refer to para -

e. Set the RPM dial at the exact LOW CA L RPM dial setting indicated

in the SELF TEST table and adjust the LOW CA L screwdriver control until

the on-off pattern of the CAL neon indicator lamp stops, or nearly stops.

f. Return the RPM dial to the HIGH CAL RPM setting. If the CAL

indicator lamp blinks on and off too rapidly, repeat steps d, e, and f.

This step is usually not necessary unless the LOW CAL adjustment was

changed substantially.

g. The RPM dial is now calibrated to within 1% on all scales.

SELF TEST DATA

RPM Dial Settings

Powe+Line

HIGH CAL

LOW CAL .

Frequency

3000

750

3600

900

400

6000

24,000

2.7.2 SELF TEST ERROR.

The action of the CAL indicator lamp is used to determine when

either of the HIGH CAL or LOW CAL adjustments are properly set. Ex -

tremely slow on-off action of the lamp indicates the calibration setting

is very close to the line frequency and generlly accurate enough for

most speed measurements. If desired, the SELF TEST error can be

calculated as follows:

a. First, observe the period (in seconds) required for the CAL

indicator lamp to complete one full cycle on to off to on again, for

example.

Then, calculate the SELF TEST error by:

RPM

= rpm error

line frequency (c/s) xT