Table of Contents
Advertisement
Under no circumstances should PTFE tape be used for sealing
the fittings as this tends to shred small particles which may
find their way into the instrument causing malfunctions.
The use of a soft setting anaerobic hydraulic seal is
recommended, (e.g. Loctite Hydraulic Seal 542). Follow the
manufacturers recommendations.
Do not use an excessive amount as this will not set and could
find its way into the instrument.
If the air supply is not of adequate quality, the device
performance can be affected. Adequate quality can normally
be achieved by the use of air filter regulators.
Electrical Installation
The electrical connections should be made as shown in the
dimensional drawing Figure 1. The instrument is protected
against reverse polarity to –100mA, no operation is possible
in this condition.
The Model 4411 approximates a constant voltage load of 6.5
volts across the loop terminals, therefore it is essential that the
loop controller be capable of providing a constant current in the
range 4-20mA with an output voltage of at least 6.5 volts.
Voltage output controllers (e.g. variable voltage power
supplies) are entirely unsuitable for the Model 4411 and could
severely damage the electronic circuits.
Important Note
The control electronics of the Model 4411 incorporate precision
electronics. The calibration of the unit may be affected by very
high voltage spikes. Consequently, in environments where static
electricity may be present ESD precautions should be used.
Wiring And Cable Entry
These instruments must be installed in accordance with
local and national codes of practice, especially for hazardous
area installations. The instruments are fully isolated from
ground and therefore grounding is unnecessary for functional
purposes. However, grounding may be necessary to conform
to installation codes.
Note: It is strongly recommended that shielded cable
or a grounded conduit be used to achieve maximum RFI
immunity, if the installation has any risk of electromagnetic
interference.
Conduit Entry
The instrument has twin conduit entry threaded 1/2" NPT. For
explosion proof installation, a sealed conduit gland conforming
to explosion-proof specifications must be used. A ground
terminal is provided both internally and externally and should
4 | BHGE
be used if ground continuity is essential.
The unit is supplied with plastic blanking plugs, which must
be removed before operation/calibration and replaced with a
blanking plug conforming to the hazardous area certification
rating applicable.
Calibration
The instruments are designed for continuous operation
without the necessity for routine overhaul, with continuous
monitoring, adequate precautions and replacement of the
filter no longer than every 5 years.
The most common source of failure for pneumatic
instrumentation has been found to be inadequate air quality,
allowing contaminants to block internal orifices. Air filtering
is included within the instrument but cannot cope with
sustained poor air quality, which may ultimately lead to failure.
The recommendations in the Pneumatic Installation section
should be rigorously observed.
Note: These instruments are factory calibrated at a supply
pressure of 30psig (2 bar).
The instrument cover must be unscrewed to obtain access to
the trimpots.
Do not remove the instrument cover in a potentially explosive
atmosphere when the instrument is powered.
An accurate current source of 4-20mA and pressure gauge are
required. These should be of good quality with an accuracy of
0.1% or better. The current source should be checked to ensure
that it provides at least 6.5V at 20mA output compliance.
• Connect the instrument as described in the installation
section or the test-jack section below.
• Remove the instrument cover to gain access to the
trimpots and jack-socket.
• Set the current to 4.00mA – the instrument outlet should
be 3.00+/-0.05psig (0.200+/-0.003 bar). Adjust the Zero
trimpot if necessary.
• For 6-30 psig output, the output pressure should be set
to 6.00 ±.05 psig (0.400 ± .003 bar). Adjust trimpot as
necessary.
• Set the current source to 20.00mA – the instrument
outlet should be 15.00 +/-0.05psig (1.00+/-0.003 bar).
Adjust the Span trimpot if necessary.
• For 6-30 psig output, the output pressure should be set
to 30.00 ±.05 psig (2.00 ± .003 bar). Adjust trimpot as
necessary.
If either Span or Zero controls are adjusted it may be necessary
to repeat the above steps until both ends are within the
calibration limits.
Alternatively the Jack Plug can be connected to calibrate and
test the unit. The Jack Plug can be either set-up for Monitoring
or Calibration/Operation set-up.
© 2019 Baker Hughes, a GE company. All Rights Reserved.
Advertisement
Table of Contents
