Oldham MX48, Руководство по пусконаладке, эксплуатации и техническому обслуживанию

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NOTE
If the ambient air is not pure, inject air using a “synthetic air” cylinder and the gas injection pipe or
a remote calibrating fixed device with a flow rate of 60 litres per hour for 25 seconds directly on the
detector or a flow rate of 170 litres per hour for 1 min 45 s using a remote calibrating fixed device.
As soon as the signal is stable on the MX48 display panel, adjust the “MEASUREMENT ZERO”
by adjusting the ZERO potentiometer (Fig. 5) and corresponding to channel to be set up, so as to
read ZERO on the MX48 display panel.
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Adjust the detector sensitivity:
- Inject the calibration gas using the gas injection pipe (or a remote calibrating fixed
device) in the same conditions as those applicable for the synthetic air (zero adjustment).
When the measurement has stabilized, set the value corresponding to the reference gas
concentration on the display panel of the MX48 unit by adjusting the sensitivity potentiometer for
the relevant channel (Fig. 5).
NOTE
For this category of explosive gas detectors, the unit’s display panel indicates 100 DIVISIONS for
100 LEL of an explosive gas.
Example:
If the reference gas is a 2.5% methane concentration, i.e. 50% LEL of methane, adjust to obtain a
display of 50 DIVISIONS.
Formula:
Maximum scale
100 DIV x n% LEL of standard gas
Number of divisions to be set =
100% LEL
Maximum LEL
- Stop the injection of the standard gas, wait for the measurement to return to zero (on the
MX48 display panel). Then, press the "CALIBRATION" key (item C, Fig 4). The
flashing yellow LED is extinguished and the "C" on the display panel disappears. The
measuring channel now operates normally an calibration has been completed.