Hach 3650 manual Calibrations, Pressure Calibration

3650 Portable O2 Analyzer - Calibrations 31 of 50

4Calibrations

4.1 Pressure Calibration

Since the instrument is sealed against moisture, you must open the barometric pressure sensor relief valve switch (on top of the instrument) to permit the instrument to achieve atmospheric pressure equilibrium, and take an accurate barometric pressure reading.

This must be done with every calibration.

To open the relief valve, depress and hold down pressure sensor relief valve switch for five seconds, then release.

If you have access to an accurate barometer, you may wish to calibrate the instrument's internal barometric pressure sensor. This is done using the PC WinLog97 program. Choose Troubleshooting, Pressure Calibration and a message will warn that the current calibration will be lost.

Fig 4-1: Pressure Calibration Screen 1

Choose OK to continue. The calibration procedure then displays a Pressure Calibration dialog box (as illustrated in Fig 4-2). The Measured Pressure value shows the current instrument pressure reading.

Note:

Since the instrument is sealed against moisture, you must open the barometric pressure sensor relief valve switch (as depicted in Fig 1-1 on page 7) to permit the instrument to achieve atmospheric pressure equilibrium, and take an accurate barometric pressure reading.

Fig 4-2: Pressure Calibration Screens 2 & 3

Enter the current atmospheric pressure, in mbars, in the Calibration Pressure entry box. Choose Calibrate to direct the instrument to read and display the Measured Pressure using this calibration value.

Choose Quit when you are satisfied with the pressure calibration to return to normal operation.

Operator Manual ORBISPHERE