Extech RF20 Operating Manual

User's Guide
Portable Salinity Refractometer with ATC
Model RF20
Introduction
Warranty
EXTECH INSTRUMENTS CORPORATION warrants this instrument to be free of defects in parts and workmanship for one year from date of shipment (a six month limited warranty applies on sensors and cables). If it should become necessary to return the instrument for service during or beyond the warranty period, contact the Customer Service Department at (781) 890-7440 ext. 210 for authorization or visit our website at www.extech.com (click on ‘Contact Extech’ and go to ‘Service Department’ to request an RA number). A Return Authorization (RA) number must be issued before any product is returned to Extech. The sender is responsible for shipping charges, freight, insurance and proper packaging to prevent damage in transit. This warranty does not apply to defects resulting from action of the user such as misuse, improper wiring, operation outside of specification, improper maintenance or repair, or unauthorized modification. Extech specifically disclaims any implied warranties or merchantability or fitness for a specific purpose and will not be liable for any direct, indirect, incidental or consequential damages. Extech's total liability is limited to repair or replacement of the product. The warranty set forth above is inclusive and no other warranty, whether written or oral, is expressed or implied.
Specifications
Scale Range Resolution
Parts Per Thousand 0 to 100 0/00 1 Specific Gravity 1.000 to 1.070 d20/
Dimensions 7.6 x 1.5 x 1.5" (194 x 38 x 38mm) Weight Approx. 8.0 oz. (227g)
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Description
1. Prism
2. Cover Plate
3. Adjustment Screw
4. Mirror Tube
5. Eyepiece
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RF20 Version 1.1 September 2003
Operation
The instrument measures the refractive index of the sample and displays the result in parts per thousand (
1. Zero Adjustment
Put distilled water on the prism; enough to cover the entire prism. Close the cover plate
and rotate the adjusting screw so that the light/dark boundary line (known as the shadow-line) evens up with the zero line. After the zero adjustment, clean the prism with soft cloth.
2. Sample Preparation and Reading
To take a reading, place a few drops of a sample liquid on the measurement prism. Ensure that enough solution is added to the prism in order to cover the entire prism. Close the prism so that the liquid spreads across the entire surface of the prism without air bubbles or dry spots (see diagrams below). Allow the sample to remain on the prism for approximately 30 seconds.
While holding the instrument under a light source, look through the eyepiece. The salinity concentration is determined by the intersection of the boundary of the light and dark fields (known as the shadow­line) on the printed scale. The left side of the scale indicates the specific gravity and the right side parts per thousand. If the scale appears out of focus, the eyepiece may be adjusted by rotating the knurled portion. The instrument also features an eye guard to prevent stray light from entering the eyepiece and causing reflections.
It may be necessary to adjust the position of the light source to maximize the contrast of the shadow-line. Under normal conditions, optimal contrast is obtained by holding the instrument underneath and perpendicular to a light source.
Once a reading has been taken, wipe dry with a clean cloth (do not wash or rinse) and place the instrument in the supplied plastic case. Store the instrument in a safe, dry environment.
Temperature is the single most important factor influencing refractometer readings and is one of the largest sources of measurement error. However, this device incorporates automatic temperature compensation and the concern for temperature fluctuations in sample liquids is alleviated. When ambient temperature varies from 68°F (20°C), readings are automatically adjusted to compensate for temperature variance between 50°F to 86°F (10°C to 30°C).
0
/00 ) and specific gravity (d 20/20).
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RF20 Version 1.1 September 2003
Calibration and Repair Services
Extech offers complete repair and calibration services for most of the products we sell. For periodic calibration, NIST certification or repair on most Extech products, call customer service for details on services available. Extech recommends that calibration be performed on an annual basis to ensure calibration integrity.
Copyright ©
All rights reserved including the right of reproduction in whole or in part in any form.
Support Hotline (781) 890-7440
Tech support: Ext. 200; Email: support@extech.com Repair/Returns: Ext. 210; Email: repair@extech.com
Website: www.extech.com
2003 Extech Instruments Corporation.
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RF20 Version 1.1 September 2003
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