Span 2 Calibration - Honeywell MiniRAE 3000+ User Manual

Span 2 calibration

The minimum value of Span 2 gas should be 1000 ppm. If the primary concern is accuracy at
low concentration, only using the 2-point calibration process with Span 1 set to 100 ppm is
adequate. The reading error at 10 ppm will be lower. If Span 1 is set to 10 ppm, the reading
error under 100 ppm (or over 100ppm to 1000 ppm) will be higher. A cylinder of standard
reference gas (span gas) fitted with a 500 cc/min. flow-limiting regulator or a flow-matching
regulator is the simplest way to perform this procedure.
Note: This gas should be of a higher concentration than the gas used for Span 1 calibration.
Choose the 500 cc/min. regulator only if the flow rate matches or slightly exceeds the flow rate
of the instrument pump. Alternatively, the span gas can first be filled into a Tedlar bag or
delivered through a demand-flow regulator. Connect the calibration adapter to the inlet port of
the instrument, and connect the tubing to the regulator or Tedlar bag.
Another alternative is to use a regulator with >500 cc/min flow but allow the excess flow to
escape through a T or an open tube. In the latter method, the span gas flows out through an
open tube slightly wider than the probe, and the probe is inserted into the calibration tube.
At the Span Calibration menu, you perform a Span calibration. You may also go back to the Zero
calibration menu or to the initial Calibration menu if you want to exit calibration.
Press [Y/+] to enter Span 2 calibration.
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Press [N/-] to skip Span calibration and return to Zero calibration.
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Press [MODE] to exit Span calibration and return to the top calibration menu.
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If you have pressed [Y/+] to enter Span calibration, then you will see the name of your Span gas
(the default is isobutylene) and the span value in parts per million (ppm). You will also see this
message that prompts you:
Please apply gas...
1. Turn on your span calibration gas.
2. Press [Y/+] to initiate calibration.
Note: You may press [MODE] if you decide that you do not want to initiate calibration. This
will take you directly to the Calibration menu for Zero calibration.
3. Span calibration starts a 30-second countdown and displays this message:
Calibrating...
During the Span calibration process, the instrument performs the Span calibration
automatically and does not require any action on your part.
Note: If you want to abort the Span calibration process, press [N/-] at any time during the
process. You will see a confirmation message that says "Span is aborted!" and then the Zero
calibration menu will appear. You can then proceed to perform a Zero calibration, perform a
Span calibration, or exit to the topmost Calibration menu.
Handheld PID Monitors 65 User Manual