Accumet AP74 Operating Instructions Manual

Accumet AP74 Operating Instructions Manual Manual pdf 16 page image

155. MeasurementTaking DO readingsDuring measurement, the probe can be:• fully immersed in the solution• partially immersed in the solutionDo not allow the probe’s membrane surface to touch any-thing! The probe guard (the piece with holes fitted over theend of the probe) protects the membrane; you should leavethis piece attached to the probe at all times.IMPORTANT: since the DO probe consumes oxygenfrom the sample, the sample must constantly flow past themembrane to achieve more accurate readings. You can usea stirrer to accomplish this.To take measurements:1. Rinse the probe well with deionizedrinse water or rinse solution.2. Select the appropriate measurementmode. Press the MODE key to togglebetween modes:• %saturation.• mg/l (ppm)**,• date/time clock3. Dip the probe into the sample. Stir theprobe gently to homogenize the sample.Make sure that the sample is continuouslyflowing past the membrane sensor.4. Note the reading on the display. If theREADY indicator is switched on, it willappear when the reading is stable.See figure5. Press the key to activate the backlitLCD. This helps you read measurementsin dimly lit areas. The backlit displayautomatically turns off 20 seconds afterreleasing the key to conserve batteries.5.1AAProbe guard**To select between mg/l and ppm units, see page 33.The ATC indicator should appear in the lower right hand corner of the display.If it does not, this indicates an error.CONTINUED ON NEXT PAGE