Pressure Transmitter
Accuracy 0.25 %
Temperature drift <0.005 % of FRO*/˚C
HART compatible
Membrane made of 96 % alumina ceramics
Body in titanium for seawater applications or
AISI 316 L
Rugged construction
Application and general description
The N-type of the GT403 Pressure transmitter,
with the flow channel in the front adapter, is
designed to be submerged in ballast and service
tanks, to measure levels in the tanks. Other types
of the transmitter can also be used to measure
pump pressure (suction and pressure side) on
submerged ballast pumps, or other submerged
equipment. The pressure transmitter can be
delivered as an absolute type or a sealed gauge
type, with pressure ranges from 0.6 to 40 Bar.
Other pressure ranges may be delivered. Zero
and full range (4 to 20 mA) may be adjusted with
a PC and HART modem or a HART
Communicator. Maximum downscale is 1/6 of
full range. For seawater applications a sensor
with front adapter in Titanium is available.
Mechanical design
The transmitter consists of a piezo resistive
sensing element together with an electronic unit
encapsulated in the sensor body. The body is
made of titanium for submerged installation in
seawater or stainless steel, where the N-type has
the flow channel in the front adapter to reduce
clogging of the pressure inlet.
Pressure sensing capsule
The pressure transmitter is built around a dry,
robust measurement capsule, made of ceramic,
with internal strain gauge Weathstone-bridge as
a converting element between pressure and
electrical signal, see Figure 3. A relative large
diaphragm of 96 % alumina ceramics in front of
the element is exposed to the pressure media. On
back side of this diaphragm, the Weathstonebridge is applied by the well-known thick-film
procedure. By high temperature treatment these
resistors are stabilized. By the fixed structure to
the ceramic diaphragm, the strain gauge effect
will occur when pressure is applied, and the
diaphragm is bending. The signal given by this
strain gauge is then digitized and stored together
with known applied pressure and temperature.
All this together forms a unique tabular for each
sensor, which is kept in sensor memory for the
sensor’s lifetime. This gives a possibility to
linearize and temperatures compensate each
sensor uniquely, based on each element’s
character. This enables a much higher accuracy
and temperature stability than with former
analogue sensors. As the 96 % alumina
membrane is resistant to most chemicals, the
process medium is in direct contact with the
measuring membrane, thus there is no need for
costly de-coupling in the form of a filling liquid
and second membrane. A filling liquid and a
second membrane will also be the source of
errors. That is why dry capsule sensors have
superior specifications compared to wet
Electrical description
The pressure transmitter is connected to a 24
VDC power supply, 4 to 20 mA, and 2-wire
connection. An electronic unit in the transmitter
gives stabilised voltage to the pressure capsule.
Out from the pressure capsule a voltage signal
linear with the pressure range is converted to 4 to
20 mA in the same electronic unit.
Power supply
Power supply to the transmitter is 24 VDC
nominal, and can vary from 12 to 35 V. The
allowable load is determined by the minimum
power supply, see Figure 1.
Electrical connection
A Cu-screened cable, with intact screen, must
always be used from the transmitter to the
monitoring system. Minimum cross cable is 2 x
0.5 mm2. The transmitter is supplied with a
Polyurethane cable flanged to the transmitter and
the cable screen is grounded in the Polyurethane
cable flanged to the transmitter. The cable screen
is grounded in the transmitter and must also be
grounded in the connection box on deck.
Screened cable must also be used on deck and
the screen must be connected to ground in the
gland on the connection box on deck as near to
the inlet of the monitoring system/cabinet as
possible, see Figure 4.
For level measurement in ballast tanks, the
transmitter is installed near the bottom of the
tank and measures the static pressure from the
liquid column plus the atmospheric pressure. As
this transmitter is an absolute pressure
transmitter, atmospheric pressure measurement is
necessary to calculate the level. A Polyurethane
Cable connects the transmitter to a connection
box on deck, see Figure 2. For detailed
installation, see “Technical Information and
Application Guidelines”, order key PGT400/KE.
Intrinsic safety
Using a Zener barrier, i.e. the DZ-110
Transmitter Barrier, the transmitter can be used
in hazardous areas.
Fig. 1:
Load vs.
Power supply
Technical specifications
Power supply:
Output signal:
Load resistance:
Sensor output current (mA):
Maximum output current (mA):
Output current with sensor fault (mA):
HART compatible:
Temperature drift:
Compensated temperature range:
Operating ambient temperature:
Storage temperature:
Long term stability:
Protection grade:
Generic EMC standard
Performance degradation during immunity test:
24 VDC (12 to 35 VDC depending on load resistance)
4 to 20 mA
0 to 1150 ohm depending on power supply
3.8 < Iout < 21.5
Iout > 21.5
Conformance class #2
< 0.25 % of FRO*
< 0.005 % of FRO*/˚C (0 to 60 ˚C)
0 to 60 ˚C
-40 to 85 ˚C
-45 to 100 ˚C
< 0.3 % of FRO*/year
0.3 kg
Intrinsic safety:
IP68, 6 bar
NEMKO Certificate reference:
Ex classification:
EN 50081-1
EN 50081-2
< 0.5 % of FRO*
Safety data:
Maximum input voltage:
Titanium grade 2 or AISI 316
Maximum input power:
L, minimum 2.5 % Mo
Maximum input current:
96 % alumina ceramics
Maximum internal capacitance:
Viton – Nitril, see order key
Maximum internal inductance:
EEx ia IIC T5
Ui = 30 V
Pi = 0.85 W
Ii = 130 mA
Ci = 22 nF
Li = 4 µH
*FRO = Full Range Output.
**Accuracy including non-lineraity, hysteresis and reliability at 22 ˚C. If Pc = Pressure range of element and Pm =
Programmed measurement range for 4 to 20 mA output then: Accuracy = 0.1 % FRO*Pc/Pm.
Based on dwg. no.: GT-1098
Based on dwg. no.: GT-1094
Fig. 2: Flange with polyurethane cable
Based on dwg. no.: E-2635
Fig. 3: Pressure sensing capsule -------0470
II 1 G EEx ia IIC T5
Nemko 02ATEX119X
Fig. 5: Drawing of the GT403 sign
Fig. 4: The GT403 Pressure Transmitter,
electrical connection
Ordering key
GT4 0 3
GT400 series
Pressure connection and material of wetted parts
V= ISO228-G1/2A, AISI316, Viton (other than
Flange, side mounted, AISI316, Viton (GT301)
K =ISO228-G1/2A, AISI316, Isolast J9503
N =ISO228-G1/2A, Titanium, Viton **)
L =O-ring made of Nitril
D =Front adapter in Titanium Viton O-ring
Output signal
0 = 4 to 20 mA
Pressure range in Bar
Application / mechanical design
3 = Ballast tanks/inert, submerged, Ex approved
A = 0.25 % FRO 0.005 % FRO/°C 0 to 60 °C
E = 0.9 % FRO -30 to 70 °C *)
F = 0.45 % FRO -30 to 70 °C *)
Zero point
A = 0 Bar absolute
C = 0.8 Bar absolute
H = 1.0 Bar absolute
*) Included un-linearity, temp.shift and hysteresis
**) Front adapter with a flow channel. Suitable for
submerged , and level gauging.
Cable gland
0 – NA (Own flange with polyurethane cable)
Order key, cable:
GT-1234/350 (Titanium)
GT-1094/350 (AISI 316)
Mechanical design
Total length, CL (dm)
Options are available. Please contact Kongsberg Maritime AS.
NO-7005 Trondheim Norway
Telephone: +47 73 58 10 00
Telefax: +47 73 58 10 01