TROLL 9500 Operator's Manual - Geotech Environmental Equipment

Section 3: Getting StartedThe Quick Calibration Wizard starts. A screen like this is displayed.Status indicators during stabilization:NOT TESTED may be displayed before the calibration begins.7UNSTABLE indicates the sensor response does not meet thecriteria for a valid calibration point. All parameters start out at“Unstable” status.NOMINAL indicates the change in the sensor response overtime meets a relaxed stability criterion. “Nominal” stability willoccur first, and can be accepted to shorten the calibration time.STABLE indicates the change in the sensor response over timemeets the stability criteria for a Quick Cal.Reading: Current sensor response (in indicated units).7. Insure there is a check beside the sensors you wish to Quick-Cal.8. Click Next. The pH, ORP, and Conductivity screen appears.8Deviation: Change in response between the last two readings.This enables you to follow the progress of the stabilization, butdeviation from the previous reading is not necessarily the bestindicator of stability as the software is looking at longer-termtrends.Run button: Starts the calibrationAccept button: Becomes available when Nominal stability isreached (see below)Stop button: Stops the current phase of the calibrationBack button: Goes to the previous screen (when available)Next button: Proceeds to the next screen (when available)Cancel button: Cancels the calibration9. Click Run to start the calibration.9The display will continuously update as readings are taken andcompared against the stabilization criteria (see sidebar).All 3 parameters must indicate NOMINAL or STABLE before thecalibration can continue.• When pH, ORP, and conductivity are STABLE, the polarographicD.O. calibration screen is displayed automatically if a polarographicD.O. sensor is installed.Q:A:What is the difference between NOMINAL and STABLE?To meet the criteria for a valid calibration point, the change(deviation) in sensor response is monitored over time. Thesoftware is looking for the calibration solution temperatureand the sensor readings to settle over a specific time period.The criteria for STABLE are designed to meet the publishedspecifications. The NOMINAL criteria are designed toshorten the calibration time when an approximate calibrationis acceptable. When the deviation falls within the limits ofthe “loosened” specifications, NOMINAL is displayed in theStatus area, and the Accept button becomes available tostore the current calibration point.Accepting a NOMINAL value may save considerable time.In some cases, especially if the sensors have been soakingin the solution for several minutes prior to calibration, theaccuracy achieved by accepting a nominal value may bevery similar to that obtained by waiting for complete stability.TROLL 9500 Operator’s Manual18 0095110 rev. 007 01/09