Sensitivity Adjustment - Dräger PEX 3000 Gebrauchsanweisung

Sensitivity adjustment

Before sensitivity adjustment the zero point must be adjusted!
 Navigate by means of keys ▲ or ▼ until the display shows SP ("SPan") and
enter the menu by pressing the keys (▲+▼). The output signal is set to 3.4 mA
to signal the calibration procedure mode to the controller unit.
— The display shows the span gas concentration used during the previous
calibration procedure in %LEL.
 By means of the keys ▲ or ▼ the concentration of the currently used span gas
can be adjusted between 20 and 99 %LEL in steps of 1 %LEL.
— The display of type XTR 0010 shows a decimal point, so the gas concentration
of the currently used span gas can be adjusted between 2.0 and 9.9 %LEL in
steps of 0.1 %LEL.
— Pressing the keys for longer activates a repeat function.
Recommended span gas concentration:
Transmitter
Typ XTR 0000
Typ XTR 0010
The span gas must be a mixture of the gas to be monitored in air!
Mixtures with nitrogen are not suitable!
 Press (▲+▼) and – depending on the current transmitter type (see table) –
apply the recommended gas concentration at a flow rate of ca. 0.5 L/min via the
calibration adapter.
 Wait until the reading has stabilised (max. 3 min) and press keys (▲+▼) to
calculate 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 longer than four minutes.
After sensor replacement the internal amplification of the transmitter can be so
high that the measured concentration cannot be displayed. The display will show
then "99" or "9.9". Nevertheless press keys (▲+▼) to calculate the necessary
internal amplification, save it, and repeat the sensitivity adjustment.
 Press keys (▲+▼). The newly calculated amplification factor is finally saved.
The display shows a reference value proportional to 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 (or with the type
XTR 0010 divide it by 10), e.g.:
— If after sensitivity adjustment of the type XTR 0000 by means of 52 %LEL
propane a reference value of 45 is displayed, so the true sensitivity of the
DrägerSensor PR M DD for propane is 45
Full scale deflection
100 %LEL
10 %LEL
CAUTION
NOTICE
2 / 100 = 0.9 mV/%LEL.
*
Span gas concentration
30 to 70 %LEL
3 to 7 %LEL
Calibrating transmitter
45