Locking Alarms; Setting The Sensor Current; Calibrating/Adjusting The Polytron Se Ex Sensing Head; Maintenance - Dräger Polytron SE Ex PR M1 DQ Notice D'utilisation

– Although the sensing heads have been factory-tested before delivery, the
commissioning process following installation must include zero-point and
sensitivity testing. The commissioning process must be concluded with a
functional test of the complete gas detection system.
– In the case of a strong flow there are no distortions of the measured values,
however up to 16% LEL higher measured values are displayed in the case
of a strong flow with 50 % LEL test gas.
– In conjunction with a REGARD control unit or Polytron transmitters with
preset alarm thresholds, acoustic and visible alarm devices or automatic
countermeasures may be initiated before the detected gases or vapours can
form dangerous flammable mixtures with air.
– The DrägerSensor PR M/HT/NPT DQ and LC M/NPT sensors can be
damaged temporarily or permanently in the presence of sensor poisons.
Sensor poisons are hydrogen sulphide, hydrocarbons containing sulphur,
and volatile silicon bonds. To a lesser extent, frequent exposure to high
concentrations of halogenated or nitrogen-containing hydrocarbons may
impair the sensor properties. Sensor poisoning is typically first manifested in
a decrease in sensitivity to methane. Sensitivity to other combustible
substances is generally less impaired.
4.3.1

Locking alarms

For tests or settings, it may be necessary to lock the alarm evaluation in
downstream devices. Follow the instructions in the instructions for use for the
relevant device.
WARNING
An alarm lock does not generate any electrical signal to indicate the alarm lock.
► To prevent the gas warning system remaining in this unsafe condition,
organisational measures must be implemented (e.g. warning sign,
information provided by the safety officer).
4.3.2

Setting the sensor current

The DrägerSensor PR M DQ, PR NPT DQ and HT M DQ sensors are operated
with 255 mA.
For backwards compatibility, the DrägerSensor PR M DQ and PR NPT DQ
sensors can be operated with a sensor current of 270 mA.
The DrägerSensor LC M and LC NPT sensors are operated with 276 mA.
The sensor current and warm-up time can be found in the instructions for use
for the sensors.
4.3.3 Calibrating/adjusting the Polytron SE Ex sensing
head
Follow the instructions for use for the sensors and the corresponding devices.
5

Maintenance

5.1

Servicing and maintenance

5.1.1

Service intervals

Observe standard EN 60079-29-2 and the relevant national laws and
regulations.
Daily:
– Visual inspection to establish readiness for operation.
During commissioning:
– Set the sensor current. For further information, see the following chapter:
"Setting the sensor current", page 38.
– Calibrate and adjust the sensing head. For further information, see the
following chapter: "Calibrating/adjusting the Polytron SE Ex sensing
head", page 38.
At regular intervals,
as specified by those responsible for the gas detection system, and not
exceeding an interval of 6 months:
– Check signal transmission to the control unit and alarm activation - see the
instructions for use of the control unit being used.
– Calibrate/adjust the sensing head. For further information, see the following
chapter: "Calibrating/adjusting the Polytron SE Ex sensing head", page 38.
The interval for regular calibration depends on the operating conditions.
Maintenance