TROLL 9500 Operator's Manual - Geotech Environmental Equipment

Section 11: pHE ois related to the potential of the reference electrode,R is the Gas Law constant,F is Faraday’s constant,T is the temperature in Kelvin,n is the ionic charge (+1 for Hydrogen), and[H + ] is the hydrogen ion concentration in moles/L.The MP TROLL 9500 reads the signal from the pH electrode, thereference electrode, and the temperature and then calculates the pHusing the Nernst equation.Sensor InstallationThe MP TROLL 9500 may be shipped with a pH or combination pH/ORP sensor installed. If installation is necessary, unpack and installthe sensor in the MP TROLL 9500 as follows.A combination pH/ORP sensor will work properly only inport 1. A pH sensor may be installed in port 1 or 3.TIP: To ensure optimum response for a new or previouslystored sensor, rinse off the soaking solution, then soak thesensor in clean water for at least 15 minutes before calibrating.1. Remove the restrictor or Cal Cup from the front end of the MPTROLL 9500. This allows access to the sensor block shown below.2. Remove the sensor hydration bottle and set aside for future use.3. Rinse the sensor in clean water to remove the soaking solution.Soak the sensor in clean water for at least 15 minutes beforecalibrating.4. Remove any moisture or dirt from the area aroundthe port where you will install the sensor, then use thesensor removal tool to remove the plug from the port.Retain the plug for future use.5. Remove any moisture or dirt from the port connectorwith a clean swab or tissue.sensorremovaltool6. Remove the cap from the sensor connector. Check lubrication ofthe o-rings. If they appear dry, apply a silicone lubricant beforeinstallation.7. Visually align the sensor connector pins with the port connector pins.8. Press the sensor into the port until you feel it dock with the port connector.When properly inserted a small gap (the width of the sensorremoval tool) remains between the instrument body and the widestpart of the sensor, for ease of removal.CalibrationOverviewSeveral options are available for pH calibration.• Quick Cal: Calibrates all basic sensors (pH, ORP, polarographicD.O., conductivity) at the same time with one convenient solution. Aone-point calibration in pH 7; default slope, calculated offset.• Traditional calibration–1 point: requires a single solution; resultsin calculation of sensor offset for a single pH value (pH 4, 7, or10). Select a calibration solution for the region of the pH range youexpect to measure. A one-point calibration may be used with goodresults when the sensor is new.• Traditional calibration–2 point: requires two solutions; results incalculation of sensor slope and offset for one pH range (pH 4-7 orpH 7-10). Choose solutions that bracket the expected pH range:pH Sensor PositionspH/ORP Sensor PositionPressure/Turbidity(or plug)Pressure/Turbidity(or plug)TemperatureTemperatureInstall a pH sensor inport 1 or port 3alignment markInstall a pH/ORPsensor in port 1alignment markTROLL 9500 Operator’s Manual 670095110 rev. 007 01/09