Rae MiniRAE Plus PGM-76, Operation And Maintenance Manual

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SECTION 3 OPERATION OF ACCESSORIES
3 - 11
3.7 Dilution Probe
A dilution probe device is offered as an accessory to the
MiniRAE Plus Professional PID unit. This device mixes one
part of incoming gas sample with 9 parts of clean air to dilute
the concentration of the gas sample by 10 times. The clean air
is obtained through a charcoal filter.
Install dilution probe :
Remove the regular probe. Make sure that O-ring and a
membrane filter remain inside the hole on the front of the sensor
block. Screw on the dilution probe.
Calibrate dilution probe :
In the factory, the dilution probe is preset at approximately 10:
1 ratio with about 5-10% error. User can adjust the dilution
probe during calibration using a 5/64" Allen wrench to achieve
exact 10:1 ratio. Here is how:
Step 1 : Connect the "zero gas" to the probe, follow the
instructions in section 4.8.1 to calibrate the zero gas.
Step 2 : Follow the instruction in section 4.8.2 to enter the
standard reference gas value.
Note: enter only 1/10 of the
actual value of the standard gas, not the actual value. For
example, if the calibration gas is 500 ppm, enter 50 in this step,
do not enter 500.
Step 3 : Connect the standard reference gas to the probe.
Turn on the gas, press [enter] key on the MiniRAE. Wait for
about 30 seconds until the gas reading appear on the LCD