3 | Baker Hughes
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To meet the EMC specifications, screened cable should be
used for installation. The cable screen should be connected to
the internal earth bonding point of the I/P. An earth strap should
also be connected from the external earth bonding point of
the I/P to a common earth point. The cable screen should not
be connected at the signal source when used in Intrinsically
Safe (IS) environments. The I/P has been thoroughly tested in
accordance with:
Electromagnetic compatibility (EMC)
Generic Standards – Immunity for industrial environments
Electromagnetic compatibility (EMC)
Generic Emissions Standard – Industrial environment
Please consult wiring diagram for further information. The results
obtained from these tests show that with the screen arrangement
shown in the installation diagram, the typical sustained output
pressure shift is <+/-5% full scale. Consult supplier for further
details�
Instrument Mounting
The converter can be mounted directly onto a valve, onto any
suitable flat surface, or onto 2” (50mm) pipe. Dimensional details:
Figure 2
These converters will operate in any position, with slight re-
calibration adjustments, normal operation is in the upright
position, i.e. with the screwed lid horizontal. The unit is weather
resistant when the lid is removed for connection or calibration,
but should not be left uncovered during operation or for extended
periods of time. They are unaffected by shock and vibration, but
severe vibration environments are best avoided.
The instruments are protected against environmental effects, to
a level of Type 4X (IP66). Sensible positioning should be used if
the local environment is severe.
Temperature compensation is designed into these converters
which will operate over a range from –40° to +85°C (-40° to
+185°F). Maximum life is obtained if extreme temperature cycling
is avoided. In extreme direct sunlight, sun-shading is advised.
The pneumatic exhaust and the bleed are routed through the
baffles. The baffles must not be blocked with paint and/or plastic
sheeting etc�
Captured Bleed Version
The baffles and the baffle cover are fitted to maintain the adequate
Ingress Protection (IP) rating of the instrument. Removal of these
protective parts will invalidate the IP and the NEMA 4X rating of
the instrument�
For captured bleed installation, remove the baffle cover and
unscrew both the baffles, fit 1/8" NPT fittings to two separate
lengths of pipes, to exhaust and bleed gas to a safe area
installation�
Vented gas from the enclosure through bleed port must not
be re-circulated and introduced back into the process stream.
Exhaust port installation must not have any restriction to create
backpressure to cause instrument to malfunction. Instrument
installation for captured bleed version must be under the
installer’s discretion.
Note: Exhaust Port is nearer the conduit entry (LH side)
Enclosure Bleed Port is on the RH side. (See Figure 3.)
Figure 3
Pneumatic Installation
These instruments are recommended for use with clean, dry, oil
free instrument grade air to BS.6739 or ISA-7.0.01-1996.
Dew Point: At least 10°C (18°F) below (-40°C) minimum
anticipated ambient temperature.
Dust:
Filtered to below 50 microns.
Oil Content: Not to exceed 1ppm mass.
The instrument is factory calibrated with a supply pressure of 30
psig (2 bar) ±10%. Operation is possible at any pressure between
18 and 150 psig (1.3 to 10 bar), though recalibration may be
necessary towards these limits to maintain specified accuracy.
The inlet and outlet ports are threaded 1/4" NPT female and
suitable fittings should be used. For most installations 1/4" (6mm)
pipe will be adequate. If a large actuator, high flow rates or long
pipework is necessary then a larger diameter should be used.
Plastic tubing, e.g. Nylon is preferable where circumstances
permit, since it is normally very clean internally. In all cases,
purge the supply pipework before connection to the converter.
Two gauge ports are provided to facilitate direct mounting of
a pressure gauge. To use one of these ports remove the plug
(using a 1/4" or 3/16" Hexagon Key) in a de-pressurized state,
and connect the gauge. The ports are threaded 1/4" NPT at the
back of the unit and 1/8" NPT at the front.
Exhaust Port
Enclosure Bleed Port
