Instruction manual

7.0 STARTUP SM425 INSTRUCTION MANUAL
5. After the measured value has stabilized, press the [Enter] key to display the “span-calibration
complete” display screen shown in Figure 7-27. At this point, the measured value is corrected to
the span-gas concentration setting. Close the span-gas flow valve. The valve lock-nut should be
tightened completely to prevent the span gas from leaking.
Figure 7-27 Span Calibration Complete
6. Select Zero calibration as shown in Figure 7-27 to display the zero-gas concentration check
display. Verify the concentration value displayed is the correct value for the reference zero gas. If
it is, select “Next” as shown in Figure 7-28.
Figure 7-28 Zero-gas Concentration Check Display
7. Follow the prompt in Figure 7-29 to establish the zero gas flow. Open the zero-gas flow valve of
the Flow Setting Unit by loosening the valve lock-nut and slowly turning the valve shaft
counterclockwise. Set the flow to 600 ± 60 ml/min. as measured by the calibration gas flowmeter.
Figure 7-29 Zero-gas Flow Display
42500001 REV A 117