Instruction manual

SM425 INSTRUCTION MANUAL 7.0 STARTUP
2. Select Manual calibration and press the [Enter] key. The Manual calibration display shown in
Figure 7-24 then appears. Verify the concentration value displayed is the correct value for the
reference span gas. If it is, select “Next”.
Figure 7-24 Manual Calibration
3. Follow the prompt in Figure 7-25 to establish span gas flow. Open the span-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 7-25 Span-gas Flow Display
4. After the span gas flow has been established, select “Valve opened” as shown in Figure 7-25. An
oxygen-concentration trend graph appears (see Figure 7-26). The CAL TIME in the bottom area
of the panel flashes. Observe the trend graph and wait until the measured value stabilizes in the
vicinity of 21% on the graph. The graph shows the concentration before calibration, so the value
may not be correct at this point.
Figure 7-26 Manual Calibration Trend Graph
116 42500001 REV A