Ultima MOS-5 Detector
27
Figure 18: Portable Purge Calibrator
NOTE:
Do not store the cylinder with the regulator fully engaged in the cylinder valve.
To calibrate, make sure the portable purge calibrator contains a gas concentration equivalent to
50% of full-scale for the unit that is going to be calibrated. Ensure that the sensor is seeing
clean air. If it is suspected that hydrogen sulfide gas is present, it will be necessary to purge the
sensor environment with clean air.
Place the gas cup over the sensor and initiate the calibration sequence, by placing the magnet
over the MSA logo on the cover of the unit. When the letters “
AC
” appear in the display
window, remove the magnet and apply the calibration gas (50% of full-scale) by opening the
valve on the cylinder. When the sensor begins to see the gas, the display will change from “
AC
”
to “
CP
” to indicate “Calibration in Progress”. When the calibration sequence is complete, the
display will change from “
CP
” to “
CC
” to indicate “Calibration Complete”.
Remove the gas by closing the valve on the cylinder, and remove the cup allowing the sensor
to see clean air. The display will change from “
CC
” to indicate a few parts per million (ppm) and
then drop to “
0
”. The unit is now calibrated and the new values have been stored in the
EEPROM (non-volatile memory). See Section 9.5 for available equipment.
