Hanna Instruments HI 9810 Instruction Manual

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Hanna Instruments HI 9810 Instruction Manual Manual pdf 6 page image

1110The TDS value in aqueous solutions is directly proportional to conduc-tivity. The ratio between the two parameters depends on the solution.HI 9810 has a fixed conversion factor set to 0.5. This means that1 μS/cm is equal to 0.5 mg/L of TDS.EC/TDS CONVERSION FACTOREC/TDS CONVERSION FACTOREC/TDS CONVERSION FACTOREC/TDS CONVERSION FACTOREC/TDS CONVERSION FACTORThe conductivity of an aqueous solution is the measure of its ability tocarry an electrical current by means of ionic motion.The conductivity invariably increases with increasing temperature.It is affected by the type and number of ions in the solution and bythe viscosity of the solution itself. Both parameters are temperaturedependent. The dependency of conductivity on temperature is ex-pressed as a relative change per degree Celsius at a particulartemperature, commonly as percent per C.For common ionic solution, this value is about 2%/C. Acids, alkalisand concentrated salt solutions have somewhat lower value, typically1.5%/C.Since a small difference in temperature causes a large change inconductivity, it is necessary to compensate for conductivity readings athigh and low temperature. The readings are usually normalized at25C.HI 9810 automatically compensates for temperature differences witha built-in temperature sensor circuitry. With this compensation, thedisplay shows the readings at 25C (77F).TEMPERATURE COMPENSATIONTEMPERATURE COMPENSATIONTEMPERATURE COMPENSATIONTEMPERATURE COMPENSATIONTEMPERATURE COMPENSATIONFor temperature compensation during calibration, please refer to thefollowing chart.pppppH VALUES AT VARIOUSH VALUES AT VARIOUSH VALUES AT VARIOUSH VALUES AT VARIOUSH VALUES AT VARIOUSTEMPERATURESTEMPERATURESTEMPERATURESTEMPERATURESTEMPERATURESTEMP pH VALUES°C °F 4.01 6.86 7.01 9.18 10.01051015202530354045505560657032415059687786951041131221311401491584.014.004.004.004.004.014.024.034.044.054.064.074.094.114.126.986.956.926.906.886.866.856.846.846.836.836.846.846.856.857.137.107.077.047.037.017.006.996.986.986.986.986.986.996.999.469.399.339.279.229.189.149.109.079.049.018.998.978.958.9310.3210.2410.1810.1210.0610.019.969.929.889.859.829.799.779.769.75For instance, if the buffer temperature is 25C, the display shouldshow pH 4.00 or 7.00 or 10.00.If the buffer temperature is 10C, the display should show pH 4.00or 7.10 or 10.20.If the buffer temperature is 50C, the display should show pH 4.10or 7.00 or 9.80.