User manual HANNA INSTRUMENTS HI 96821

[. . . ] 6 CALIBRATION PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 MEASUREMENT PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 TO CHANGE MEASUREMENT UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 TO CHANGE TEMPERATURE UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] Refractive Index is an optical characteristic of a substance and the number of dissolved particles in it. Refractive Index is defined as the ratio of the speed of light in empty space to the speed of light in the substance. A result of this property is that light will "bend", or change direction, when it travels through a substance of different refractive index. When passing from a material with a higher to lower refractive index, there is a critical angle at which an incoming beam of light can no longer refract, but will instead be reflected off the interface. The critical angle can be used to easily calculate the refractive index according to the equation: sin (critical) = n2 / n1 Where n2 is the refractive index of the lower-density medium; n1 is the refractive index of the higher-density medium. In the HI 96821 refractometer, light from an LED passes through a prism in contact with the sample. An image sensor determines the critical angle at which the light is no longer refracted through the sample. Specialized algorithms then apply temperature compensation to the measurement and convert the refractive index to: g/100 g (% by mass), g/100 mL, Specific Gravity (S. G. 20/20), or °Baumé. 4 FUNCTIONAL DESCRIPTION TOP VIEW 1. 8. Liquid Crystal Display (LCD) READ Key (User Measurement) ZERO Key (User Calibration) RANGE Key (User Measurement Unit) ON/OFF Stainless Steel Sample Well and Prism Secondary Display Primary Display BOTTOM 9. 9. Battery (blinks when low battery condition detected) Measurement in Progress Tag SETUP: Factory Calibration Tag CAL: Calibration Tag Automatic Temperature Compensation (blinks when temperature exceeds 10-40°C / 50-104°F range) Primary Display (displays measurement and error messages) Temperature Units Secondary Display (displays temperature measurements; when blinking, temperature has exceeded operation range: 0-80°C / 32-176°F) Range indicator MEASUREMENT GUIDELINES · · · · · · · Handle instrument carefully. Do not spray water to any part of instrument except the "sample well" located over the prism. This includes most organic solvents and extremely hot or cold solutions. Absorb sample on soft tissue and rinse sample well with deionized or distilled water between samples. Do not use metallic tools such as needles, spoons or tweezers as these will scratch the prism. 6 CALIBRATION PROCEDURE Calibration should be performed daily, before measurements are made, when the battery has been replaced, or between a long series of measurements. Two instrument test screens will be displayed briefly; all LCD segments followed by the percentage of remaining battery life. Using a plastic pipette, fill the sample well with distilled or deionized water. Make sure the prism is completely covered. Note: If the ZERO sample is subject to intense light such as sunlight or another strong source, cover the sample well with your hand or other shade during the calibration. (For a description of ERROR MESSAGES see page 11). Note: The 0. 0 screen will remain until a sample is measured or the instrument is turned off. 7 MEASUREMENT PROCEDURE Verify the instrument has been calibrated before taking measurements. Fill the well completely. Note: If the temperature of the sample differs significantly from the temperature of the instrument, wait approximately 1 minute to allow thermal equilibration. [. . . ] Example with g/100 g NaCl: g/100 g NaCl g NaCl g Water g Total 10 10. 000 90. 000 100. 000 BATTERY REPLACEMENT To replace the instrument's battery, follow these steps: · Make sure the instrument is off. · Turn instrument upside down and remove the battery cover by turning it counterclockwise. · Extract the battery from its location. · Replace with a new 9V battery making sure to observe polarity. · Insert the back battery cover and fasten it by turning clockwise to engage. WARRANTY The HI 96821 is warranted for two years against defects in workmanship and materials when used for its intended purpose and maintained according to the instructions. [. . . ]