19
11041781.04 01/2020 EN/DE
Pressure gauge with reed contact model 851-A, for Ex areas
EN
■
With filled versions the vent valve at the top of the case must
be opened before commissioning!
■
For outdoor applications, the selected installation location has
to be suitable for the specified ingress protection, so that the
instrument is not exposed to impermissible weather conditions.
■
In order to avoid any additional heating, the instruments must
not be exposed to direct solar irradiation while in operation!
■
To ensure that the pressure can be safely vented in the case of
failure, instruments with blow-out device or blow-out back must
keep a minimum distance of 20 mm from each object.
Requirements for the installation point
If the line to the measuring instrument is not adequately stable, an
instrument mounting bracket should be used for fastening. If vibra-
tions cannot be avoided by means of suitable installation, filled
instruments should be used. The instruments should be protected
against coarse dirt and wide fluctuations in ambient temperature.
Permissible vibration load at the installation site
The instruments should always be installed in locations free from
vibration. If necessary, it is possible to isolate the instrument from
the mounting point, e.g. by installing a flexible connection line
between the measuring point and the instrument and mounting
the instrument on a suitable bracket.
If this is not possible, the following limit values must not be
exceeded:
Frequency range < 150 Hz
Acceleration < 0.5 g (5 m/s
2
)
5. Commissioning, operation
