272250-series Operating Manual rev 2.05.1.2.2 Manual CalibrationAs explained above manual calibration can be used if the probe has a very large offset, has low efficiencyor is being calibrated with non-standard buffer solutions.1. Select Manual Calibration2. Place the probe in the first buffer. As opposed to auto calibration, it is okay to press Enterwithout waiting for the probe output to settle down. The next screen will display the currentoutput reading of the probe.3. When the reading settles down press Enter. The next screen allows you to change the value ofthe displayed pH value to correspond to the actual pH of the calibration solution. Use the ↑ and↓ arrow buttons to change the value and the or → button to change the cursor position.Press the Enter key to lock in the correct value.4. The results of the calibration (identical to the one shown for auto calibration) will display.5. Place the probe in the second buffer. Again, there is no need to wait for the probe reading tosettle down prior to pressing Enter.6. When the reading settles down press Enter. Change the pH value display to equal the pH of thecalibration standard.5.1.3 3-Point CalibrationThe instructions for 3-point calibration are the same as for 2-point calibration with the obvious exceptionthat three standards are used instead of two.5.1.4 Temperature CalibrationSince all pH readings are temperature compensated, an accurate pH readings depend on an accuratetemperature.1. Select Temperature.2. The screen displays the current temperature reading. Make sure the temperature reading hassettled down. Keep in mind that most temperature elements in pH probes are encapsulatedinside the probe, which results in a temperature lag of several minutes for the element toequilibrate with the temperature of the solution.3. The temperature calibration procedure is analogous that for manual pH calibration. It’s notnecessary to immerse the probe in solution. Knowing room temperature enables you to calibratethe probe in air. As with manual pH calibration, ensure that the temperature reading settles