Sensitivity Adjustment - Dräger PEX 3000 Instrucciones Para El Servicio

Calibrating transmitter

Sensitivity adjustment

Before sensitivity adjustment the zero point must be adjusted!
Navigate by means of keys
the menu by pressing the keys (
the calibration procedure mode to the controller unit.
— The display shows the span gas concentration used during the previous calibrati-
on procedure in % LEL.
q
By means of the keys
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
Attention:
The span gas must be a mixture of the gas to be monitored in air!
Mixtures with nitrogen are not suitable!
q l
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 calibra-
tion adapter.
Wait until the reading has stabilised (max. 3 min) and press keys (
late the necessary internal amplification.
The display shows the measured value with the newly calculated amplification fac-
tor, 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.
Remark:
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 (
necessary internal amplification, save it, and repeat the sensitivity adjustment.
q l
Press keys ( + ). The newly calculated amplification factor is finally saved. The
display shows a reference value proportional to the sensitivity of the sensor (con-
stantly 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 pro-
pane a reference value of 45 is displayed, so the true sensitivity of the Ex-sen-
sor PR M for propane is 45 * 2 / 100 = 0.9 mV/% LEL.
Page 18 of 42
q l
or until the display shows SP ("SPan") and enter
q l
+ ). The output signal is set to 3.4 mA to signal
l
or the concentration of the currently used span gas
Full scale deflection
100 % LEL
10 % LEL
q
Span gas concentration
30 to 70 % LEL
3 to 7 % LEL
q l
+ ) to calcu-
l
+ ) to calculate the
9023810 - 2nd edition - September 2005