Sper Scientific 300055 Digital Refractometer Automotive - Manual (Page 5)

- 8 -
(page 6), then press the SCALES (8)
button and hold the button for 1 second to
cycle through the options.
• "- - -" is displayed and the ACTIVE
SCALE (7) indicator "▼" points to the
selected scale.
• With the desired scale selected, press the
READ
(9) button to obtain the results.
Erratic Readings
If the readings are significantly above or
below the expected results, consider the
following:
• Sample contains more than one dissolved
solid. For example, if the sample contains
both salt and sugar, a Brix refractometer
will not display the true sugar content
because the salt content will skew the brix
measurement.
• When diluting samples, be sure to use a
pure solution such as distilled water.
• Sample contains suspended solids. Filter
and thoroughly mix the sample before
testing.
• Perform a calibration.
• Replace the battery.
• Outside light can cause erratic readings,
- 5 -
3. NOTES AND PRECAUTIONS
• The refractometer will automatically shut
off after about 3 minutes of inactivity.
• After each use, clean the SAMPLE
PLATE
(1) and PRISM (3) with distilled
water on a soft cloth, and wipe dry.
• If a film develops on the PRISM (3) it will
repel test samples and affect readings.
If this occurs, clean with a mild detergent.
• The prism is easily scratched, never use
abrasive cleaning materials.
• Never submerge.
• Avoid spills around the unit.
• Avoid prolonged use or storage in
extreme temperatures.
• Do not use in corrosive environments.
• Do not drop or shake the unit.
• Use the protective carrying case to
prevent physical damage.
4. CALIBRATION
Calibration should be performed daily before
sample testing begins or when you suspect
that the reading may be inaccurate. For
best results, perform the calibration in a
controlled environment of 68°F (20°C).