Dräger PEX 1000 Notice D'utilisation page 35

4. Wait until the reading has stabilised (max. 3 min) and press keys (▲+▼) to recalculate the
necessary internal amplification.
The display shows the measured value with the newly calculated amplification factor, which
however has not been saved yet. So the original amplification factor will be restored if the
calibration menu is automatically exited by waiting for more than four minutes.
NOTICE
i i
After sensor replacement the internal amplification of the PEX 1000 can be so high that
the measured concentration cannot be displayed. The display will then show "99" or
"9.9". Nevertheless press keys (▲+▼) to recalculate the necessary internal
amplification, save it, and repeat the sensitivity calibration.
5. Press key (▲+▼). The newly calculated amplification factor is finally saved. The display
shows a reference value for the sensitivity of the sensor (constantly amplified bridge signal).
If this value is lower than 10 it is displayed with decimal point.
The true sensitivity of the sensor in mV per %LEL can be obtained by multiplying the

reference value by a factor 2 and dividing it by 100, e.g.:
If, following a calibration of the PEX 1000 by means of 52 % LEL propane, a reference

value of 45 is displayed, the true sensitivity of the DrägerSensor PR M DD/DQ for
propane is 45
The reference value and/or the true sensor sensitivity should always be recorded for test
purposes in mV/%UEG.
NOTICE
i
i
If the reference value is less than half the value recorded during commissioning of the
sensor or if the measured value does not stabilise within 3 minutes, the sensor should
be replaced.
Press keys (▲+▼) to terminate the sensitivity calibration.

Press key ▲ twice to return to measuring mode. The flashing point in the right bottom

corner is deactivated.
5.1.3 Following completion of calibration
The display shows the current gas concentration in % LEL and the 4 to 20 mA-signal of the

PEX 1000 is proportional to the current gas concentration in % LEL.
Dräger PEX 1000
2 / 100 = 0.9 mV/%LEL.
*
Maintenance
35