Ultima MOS-5 Detector
25
After 3 to 5 minutes, the display will change from “CP” to “CC” indicating that the calibration is
complete. (Figure 16).
Figure 16: Calibration Complete Mode
Remove the gas and wait for the unit to return to normal operation. Once the gas concentration
decreases, the display will read a few percent LEL and then will reach “0.”
The unit is now calibrated and the new span value has been stored in the non-volatile memory
(EEPROM).
NOTE:
The sensor life figure displayed is that calculated on completion of the last calibration.
To determine the current sensor life, calibrate unit and then repeat steps 1 and 2.
4.7.2 Aborting
Calibration
If calibration is to be aborted and gas has not been applied, wait ninety seconds and reapply
the magnet. The unit will then returns to normal operation with the previous calibration values
unchanged.
NOTE:
Once gas has been applied, it is not possible to abort a calibration.
If the Ultima MOS-5 Intelligent Sensor is placed in the Calibration Mode and no gas is applied
for 12 minutes, the unit reverts to a Fault (F2) condition. Re-applying the magnet over the MSA
logo returns the unit to operational mode with the previous calibration values unchanged.
4.7.3 Remaining Sensor Life
The Ultima MOS-5 Intelligent Sensor provides an estimate of remaining sensor life, in percent
remaining, to provide the user with an early warning of the need for sensor replacement. The
remaining sensor life is updated each time the unit is calibrated. The current remaining sensor
life estimate is displayed during the zeroing portion of a calibration sequence. It can also be
read via the Modbus or HART interface (Section 8.0).
NOTE:
Remaining sensor life is an estimate of sensor degradation derived from sensor
sensitivity. Because sensor sensitivity is affected by factors other than the natural
sensor degradation, users must establish their own reference by resetting sensor life
whenever these factors are at play. Some examples of these factors are new sensor
installations, sensor replacement, change of the target gas, and changes in the access
of gas to the sensor. If sensor life is not reset, the remaining sensor life indicator will
no longer reflect the true state of the sensor.
