Hach 1950Plus, Инструкция по эксплуатации инструмента, Страница: 121 / 188

Section 7
Page 121
UVTOCMaintenance.fm
IR Gas Calibration
Figure 46 Light Pressure Applied to Latch
7.9 IR Gas Calibration
7.9.1 IR Gas Calibration Procedure
Perform an IR gas calibration when you suspect the IR is out of calibration.
Check the carrier gas feed pressure at the carrier gas inlet first to ensure that
an adequate supply is available. Pressure should be 40-90 psig.
IR calibration requires CO
2
span gas at 1000 ppm or 10000 ppm (refer to the
configuration table in Section 5.3 on page 88 for IR span, ppm CO
2
gas
range). Zero gas can be the carrier gas. Connect the zero and span gases
directly to the IR.
If relay contacts are connected to ac line voltage, remotely disconnect
the power before opening the upper enclosure door of the analyzer. See
section 7.1 on page 111 before performing this procedure.
1. Enter the Service/Elevation menu and set the elevation to 1 meter.
2. From the Service menu, press the UP key three times to enter the IR cal
menu. The IR cal screen is displayed.
3. Press ENTER. The screen changes to display the live calculated
CO
2
ppm, the measured IR voltage, and the temperature of the IR cell.
4. Verify that the temperature of the IR cell is between 48 and 51 °C.
Apply the zero gas directly to the cell. Allow the gas to flow for ten minutes
at 200 cc/minute.
5. Using Table 11 on page 82 , determine the IR span gas concentration
(either 1000 ppm or 10000 ppm CO
2
). If the span gas is 1000 ppm, LK1
I R c a l