4 Operation | Model 3000PA | |
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of the displayed value of the oxygen concentration (in ppm) for three min- utes. Then the instrument automatically returns to the analyze mode.
4.4.2.2Manual Mode Spanning
Press Span to start the Span function. The screen that appears allows you to select whether the span calibration is to be performed automatically or manually.
Span: Settling:MAN
<ENT> For Next
Use the ∆∇ keys to toggle between AUTO and MAN span settling. Stop when MAN appears, blinking, on the display. Press Enter to move to the next screen.
Span Val: 20.90 <ENT>Span <UP>Mod #
Press ∆ (<UP>) to permit modification (Mod #) of span value.
Use the arrow keys to enter the oxygen concentration of the span gas you are using (20.90 if you are using air). The < > arrows chose the digit, and the ∆∇ arrows choose the value of the digit.
Press Enter to enter the span value into the system and begin the span calibration.
Once the span has begun, the microprocessor samples the output at a predetermined rate. It calculates the difference between successive samplings and displays this difference as Slope on the screen. It takes several seconds for the first Slope value to display. Slope indicates rate of change of the Span reading. It is a sensitive indicator of stability.
####% Span
Slope=#### ppm/s
When the Span value displayed on the screen is sufficiently stable, press Enter. (Generally, when the Span reading changes by 1 % or less of the full scale of the range being calibrated for a period of five minutes it is sufficiently stable.) Once Enter is pressed, the Span reading changes to the correct value. The instrument then automatically enters the Analyze func- tion.
4.5The Alarms Function
The Model 3000PA is equipped with 2 fully adjustable concentration alarms and a system failure alarm. Each alarm has a relay with a set of form
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