Dräger Polytron Ex, Инструкция по эксплуатации, Страница: 16 / 39

Start-Up
Page 16 of 40
9023744 - 3rd edition - October 2005
— When using the Ex-sensors LC M:
The gas concentration is display without the decimal point, so the true concentra-
tion is a tenth of the reading in % LEL.
— For calibration with solvent vapours, use can be made of the calibration chamber
(see Order List, page 31) in which a specified amount of solvent is evaporated, so
as to obtain, for example, 50 % LEL.
Adjustment is carried out as for calibration gas.
— The use of a calibration chamber requires appropriate training and knowledge on
the part of the operating personnel. Pay attention to usage instructions provided
with the calibration chamber!
If it is no longer possible to adjust sensitivity due to inadequate sensor sensitivity
(measured value to low),
or
if the measured value display does not stabilize after 3 minutes, the Ex-sensor must
be replaced (refer to page 22).
Following Completion of Calibration:
1 Set sliding switch to position »0« = normal.
2 Use special key to close flap in front of adjusters.
Calibrating Transmitter Polytron Ex R
● Use special key to open flap in front of adjusters.
1 Set sliding switch to position »1« = cal.
● The measurement signal of the 4 to 20 mA loop oscillates between 2.5 and 5 mA
with approx. 1 Hz, thus preventing alarm triggering.
● A further digit appears in the display making it possible to take more precise
readings.
Zero Adjustment
Without calibration adapter:
— Ensure that the sensing head is in clean ambient surroundings, i.e. that there are
no combustible gases or vapours present,
or
— with calibration adapter:
● Supply clean air at a rate of approx. 0.5 L/min. via the calibration adapter.
2 Wait for the display on the transmitter Polytron Ex R to stabilize (max. 3 minutes).
Set potentiometer of the transmitter Polytron Ex R such that the display indicates
00.0.
02823
7
4
4_1
.eps
1
02323
7
4
4_1
.eps
1 2
02
423
7
4
4_1_en.eps
zero gas