MODEL 54eA | SECTION 7.0 |
| CALIBRATION - DISSOLVED OXYGEN |
7.5CALIBRATING BAROMETRIC PRESSURE
1.If the barometric pressure measured by the controller does not agree with the local barometric pressure, cal- ibrate the pressure sensor. A pressure error of 3 mm Hg introduces an error of about 0.5% in the final meas- urement. When calibrating the pressure reading, be sure to use the actual barometric pressure. Weather fore- casters and airports usually report barometric pressure corrected to sea level; they do not report the acutal pressure. It is good practice to open the enclosure door before starting a barometric pressure calibration. When gland fittings are used, the controller enclosure is moderately airtight. As the controller enclosure heats or cools, the pressure of the air trapped inside the enclosure may be as much as 5% different from ambient pressure.
2.From the main display, press any key. With the cursor on “Calibrate,” press Enter (F4).
3.Press Enter (F4) to select “Calibrate main sensor.”
Calibrate main sensor
Zero main sensor
Adjust temperature
ExitEnter
Calibrate in air Calibrate in process Barometric pressure
4.Press the ê key twice to move the cursor to “Barometric pressure.” Press Enter (F4).
ExitEnter
763mm Hg
Standardize : 760
ExitEdit
5.Press Edit (F4). Use the arrow keys to change the pressure reading to the desired value. Press Save (F4) to store the value.
6.Press Exit (F1) four times to return to the main display.
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