Dräger PEX 3000, Руководство пользователя, Страница: 42 / 100

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Dräger PEX 3000
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Maintenance
6 Maintenance
6.1 Maintenance
Comply with EN 60079-29-2 and the relevant national laws and regulations.
Daily
– Visual inspection to establish operational readiness.
During commissioning
– Check the zero-point and span calibration (see "Calibrating the zero-point",
page 39).
– Check the signal transmission to the controller and alarm triggering.
At regular intervals,
as specified by those responsible for the gas detection system, and not
exceeding an interval of 6 months:
– Check the zero-point and span calibration (see "Calibrating the zero-point",
page 39).
– Check the signal transmission to the controller and the triggering of the
alarms (SL function – set the current output to X mA, (see "SL – set current
output to X mA", page 36)).
In particular, regular checks must be performed to ensure that the sensor’s
sinter disc is in a condition that does not impair the gas infeed due to corrosion
or deposits (dust, oil, aerosol).
Every six months
– Inspection by specialists.
The inspection intervals must be established in each individual case, depending
on technical safety considerations, engineering conditions, and the technical
requirements of the equipment. We recommend that a service contract be
obtained with Dräger and that all repairs also be carried out by them.
If necessary
– Replace sensor (see "Replacing the sensor", page 42).
6.2 Replacing the sensor
Only use sensors which are listed in the order list on page 27. Type XTR 0000,
XTR 0001: DrägerSensor PR M DQ, order number 68 12 220, type XTR 0010,
XTR 0011: DrägerSensor LC M, order number 68 10 350.
WARNING
The transmitter must be de-energised before replacing the sensor. Otherwise
explosion protection and the integrity of the sensor are not ensured, as this
might be damaged during live connection.
– Observe the national regulations for the installation of electrical apparatus in
explosion-hazard areas (in Europe EN 60 079-14).
– Disconnect the transmitter from the power supply or remove the controller’s
channel card from the rack.
– Loosen four screws on the top of the transmitter and remove the upper part
of the housing.
– Disconnect the sensor lines from the connection terminals. Use a
screwdriver (width of 3 mm) or special tool to open the spring terminals (see
"Handling the spring terminal clamps in the transmitter", page 34).
– Unscrew the hexagon nut from the old ex-sensor.
– Remove the old ex-sensor from the housing and replace with a new ex-
sensor. Shorten the sensor cables on the new sensor to 55 mm, strip
approx. 6 mm and apply the isolated ferrules provided (Fröhlich,
type: V3AE0003 or equivalent). This ensures that the degree of protection
IP 30 is preserved if the housing is opened for maintenance purposes.
– Screw the new sensor into the hexagon nut (via the housing opening) and
fasten with thread-locking fluid (e.g. Loctite no. 221). To preserve the IP
degree of protection, ensure the flawless fit of the sensor sealing ring.
– Connect the ex-sensor’s cables (brown, yellow, black) to the corresponding
br/br, ge/yw and sw/bk terminal. Use a screwdriver (width of 3 mm) or
special tool to open the spring terminals (see "Handling the spring terminal
clamps in the transmitter", page 34).
– Refit the upper part of the housing, ensuring that the atmosphere is free of
dust and fasten the cover screws.
– Turn the transmitter on again and/or re-insert the controller’s channel card
into the rack.
– Observe the warm-up time of the new ex-sensor of about 10 minutes.