GDU-Incus
Ultrasonic Gas Leak Detector
Quick Start Guide
00825-0100-3003, Rev AA
August 2021
Quick Start Guide August 2021
Important instructions
Emerson designs, manufactures, and tests products to function within specific conditions. Because
these products are sophisticated technical instruments, it is important that the owner and operation
personnel strictly adhere both to the information printed on the product nameplate and to all
instructions provided in this manual prior to installation, operation, and maintenance.
WARNING
Installing, operating, or maintaining an Emerson product improperly could lead to serious injury or
death from explosion or exposure to dangerous substances.
Comply with all information on the product, in this manual, and in any local and national codes
that apply to the product.
Do not allow untrained personnel to work with this product.
Use Emerson parts and work procedures specified in this manual.
Authorized personnel for installing, operating, servicing, and maintaining the GDU-Incus are instructed
and trained qualified personnel of the operating company and the manufacturer.
It is the operating company's responsibility to:
• Train staff.
• Observe safety regulations.
• Follow the Reference Manual.
Operators must:
• Have been trained.
• Have read and understood all relevant sections of the Reference Manual before commencing
work.
• Know the safety mechanisms and regulations.
To avoid personal injury and loss of property, do not install, operate, maintain, or service this
instrument before reading and understanding this reference manual and receiving appropriate
training.
WARNING
Heavy instrument
The GDU-Incus weighs approximately 40 lb. (18 kg).
Take care when lifting and carrying the unit.
Ensure that all bolts and fixings selected for mounting are suitable for the weight and that the
wall, pole, or mounting surface is solid and stable.
WARNING
Physical access
Unauthorized personnel may potentially cause significant damage to and/or misconfiguration of end
users’ equipment. This could be intentional or unintentional and needs to be protected against.
Physical security is an important part of any security program and fundamental to protecting your
system. Restrict physical access by unauthorized personnel to protect end users’ assets. This is true for
all systems used within the facility.
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NOTICE
The contents of this publication are presented for informational purposes only and while every effort
has been made to ensure their accuracy, they are not to be construed as warranties or guarantees,
expressed or implied, regarding the products or services described herein or their use or applicability.
All sales are governed by Emerson's terms and conditions, which are available upon request. We
reserve the right to modify or improve the designs or specifications of such products at any time.
Emerson does not assume responsibility for the selection, use, or maintenance of any product.
Responsibility for proper selection, use, and maintenance of any Emerson product(s) remains solely
with the purchaser and end user.
To the best of Emerson's knowledge, the information herein is complete and accurate. Emerson makes
no warranties, expressed or implied, including implied warranties of merchantability and fitness for a
particular purpose with respect to this manual and, in no event, shall Emerson be liable for any
incidental, punitive, special, or consequential damages including, but not limited to, loss of
production, loss of profits, loss or revenue, or use and costs incurred including without limitation for
capital, fuel and power, and claims of third parties.
Product names used herein are for manufacturer or supplier identification only and may be trademarks
or registered trademarks of these companies.
All rights reserved. No part of this work may be reproduced or copied in any form or by any means
graphic, electronic, or mechanical without first receiving written permission of Emerson, Shakopee,
Minnesota, United States.
Contents
Introduction.................................................................................................................................5
Installation................................................................................................................................... 7
Operation...................................................................................................................................29
HART® functionality................................................................................................................... 41
Product certifications................................................................................................................. 42
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1 Introduction
1.1 Product overview
The GDU-Incus is an ultrasonic gas leak detector used for detecting airborne
ultrasound generated from pressurized gas leaks. Airborne ultrasound is
generated when gas moves from a high pressure area to a low pressure area
with a ratio in excess of 1.8 to 1 upstream to downstream. However,
Emerson only recommends this detector for pressures above 2 bar (30 psi)
gauge. The intensity of airborne ultrasound generated is dependent on a
number of factors including gas pressure, gas leak size, and gas
temperature.
The detector uses four individual Piezo ceramic sensing heads designed
using a patent-pending floating crystal design. The sensor design makes the
sensing heads virtually indestructible and totally immune to temperature,
moisture, and other contaminants found in hazardous areas. The detector
uses a continuous electronic monitoring test feature to ensure complete
functionality.
The detector has a large dynamic range, which allows use in a wide range of
applications, from offshore platforms to gas transportation systems. The
multi-stage amplifier ensures a linear output across the entire detector
range without drop-off at each end of the range.
The detector is not designed to detect specific gas types, LEL, or ppm. It
responds instantaneously to the ultrasound produced by a wide range of gas
leak sizes and remains unaffected by even the most extreme weather
conditions. The detector is rated to IP66/IP67 and NEMA® Type 4X to
withstand harsh environments.
The detector is supplied with a 4-20 mA analog output, a HART® interface,
and two configured relays.
1.2
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Service support
For technical support, contact your Emerson representative or email
safety.csc@emerson.com.
The Response Center will ask for product model and serial numbers and will
provide a Return Material Authorization (RMA) number.
The Response Center will also ask for the installation and application details.
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WARNING
Hazardous substances
Individuals who handle products exposed to a hazardous substance can
avoid injury if they are informed of and understand the hazard. If the product
being returned was exposed to a hazardous substance as defined by the
Occupational Safety and Health Administration (OSHA), a copy of the
required Safety Data Sheet (SDS) for each hazardous substance identified
must be included with the returned goods.
1.3 Product recycling/disposal
Consider recycling equipment and packaging. Dispose of the product and
packaging in accordance with local and national legislations and regulations.
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2 Installation
2.1 Safety messages
Instructions in this section may require special precautions to ensure the
safety of personnel performing the operations.
WARNING
Failure to follow these installation guidelines could result in death or serious
injury.
Ensure that only qualified personnel perform the installation.
The area in which the detector is mounted must be in accordance with
the certification of the apparatus and in accordance with local or national
standards.
Do not modify the enclosure or component parts; this will compromise
the Hazardous Area Certification.
Ensure that all wiring and power supply to the detector is within specified
operating parameters.
Except for the terminal cover, the GDU-Incus is a sealed unit. The main
enclosure may be opened only by Emerson or Emerson-authorized
personnel. All warranties and certifications are nullified if the seals are
tampered with or broken.
The GDU-Incus is supplied without cable glands. Ensure that all cable
entry threads are sealed with an appropriate plug to eliminate water
ingress and thread damage. At installation, remove all shipping cable
entry plugs and replace them with approved Ex d cable glands or
blanking plugs to meet hazardous locations requirements. If the
detector is to be installed in a Zone 1 Hazardous Area, an Ex d barrier seal
must be used.
WARNING
Electrical hazard
Electrical shock could cause death or serious injury.
Use extreme caution when making contact with leads and terminals.
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CAUTION
Equipment damage
Identification tags must be firmly secured to the GDU-Incus bracket to
prevent unwanted, locally-generated, ultrasonic noise. Refer to Figure 2-1.
2.2 Unpack and inspect
Procedure
1. Carefully remove all components from the packaging.
2. Verify the components against the enclosed packing list.
3. Inspect all components for obvious damage, such as broken or loose
parts.
4. If any components are missing or damaged, contact your local
Emerson representative or the factory immediately.
2.3 Dimensions
Refer to Figure 2-1 for the dimensions of the GDU-Incus.
Note
Dimensions are in millimeters (top number) and inches (bottom number).
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Figure 2-1: Dimensions
A. Suitable for M10 or equivalent
B. Main body enclosure (housing)
C. Standard mounting bracket shown. U-bolt kits (for pole mounting) and a
"DNV" certified bracket are available.
D. Display
E. Sensor head (four positions)
F. Customer cable entry position available for dual entry/relay output
(ATEX/IECEx units only)
G. Terminal compartment housing
H. Customer cable entry M20 standard. M250.5 in (13 mm) NPT or 0.75 in
(19.0 mm) NPT alternative
I. Identification tag (sold separately) can be mounted on either side of
bracket using holes provided.
J. Top body enclosure (housing)
2.4
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Installation procedure
Emerson recommends mounting the GDU-Incus between 10 and 16 ft. (3
and 5 m) above the floor level to eliminate ground reflections and
absorption. You may mount the detector lower than 10 ft. (3 m), but that
may reduce the coverage; contact an Emerson representative for more
details.
Check the area of installation for equipment capable of generating high
levels of spurious airborne noise that would not be classified as "normal
background noise", such as pressure release valves, etc. If any are present in
Quick Start Guide August 2021
the detector range of coverage, contact Emerson or monitor the detector
when activated to ensure immunity.
2.4.1 Mechanical installation
The detector incorporates a dedicated flameproof terminal compartment
certified to Ex d and a flameproof main electronics compartment certified to
Ex d, both sealed to IP66/IP67.
CAUTION
Take care when removing the terminal cover during installation to ensure
that the flamepath surfaces are not scratched or damaged. See Wire the
detector for more information.
The detector has a large detection radius capability; take care when
positioning it to use the maximum coverage while eliminating blind spots
and spurious alarms.
The detector has a variety of mounting options to incorporate installation
into most situations in industrial environments, such as wall/flat surface
mounting (Mount to wall or flat surface), vertical pole mounting (Mount to a
pole), and mounting in an environment where DNV certification is required
(Mount DNV certified detector).
The detector should be mounted so that the four sensor heads are pointing
vertically downwards towards the floor or ground. See Figure 2-2.
Figure 2-2: Three-Dimensional View of Detector Coverage.
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The detector uses four independent sensor heads for full coverage. Figure
2-2 shows a three-dimensional view of the coverage (detector not to scale)
at a 10-ft. (3 m) height above floor level with the detector pointing vertically
downwards. The detector coverage is specified as meters radius at the floor
level, as this is the minimum sensing distance. As shown, the entire area
below the detector is covered, as well as some of the area above and around
the detector. Each sensor overlaps the next, so multiple sensors cover areas
underneath the detector.
2.5 Mounting
2.5.1 Mount to wall or flat surface
When mounting on a vertical flat surface, such as a wall with no significant
vibration, use the standard mounting bracket supplied with the detector. If
you suspect vibration at the fixing point, contact an Emerson representative
for additional options.
Figure 2-3: Wall/Flat Surface Mounting Diagram
Dimensions in mm.
A. Wall mounting bracket
B. Standard bracket
C. Floor
D. Vertical mounting locking fastener, typical both sides
E. Roof
F. See Step 3.
G. See Step 2.
H. See Step 1.
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Note
GDU-Incus assembly weight: approximately 40 lb. (18 kg). Ensure fixings are
capable of supporting assembly weight and local standards for shock
loading.
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Figure 2-4: Wall Mounting Drilling Template
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Figure 2-4 shows the position of the mounting slots on the wall mounting
bracket supplied with the standard GDU-Incus. Drill pairs of Ø 0.4-in. (10
mm) holes on the mounting surface between 1.2 in. (30 mm) and 2.8 in. (70
mm) apart, with a vertical distance of 7.48 in. (190 mm) between the two
pairs of holes.
Procedure
1. Attach wall mounting bracket to wall of flat horizontal support using
four M10 bolts.
2. Position the detector so that the standard bracket is on the studs of
the wall bracket. Secure the brackets together using the two M10
nuts supplied.
3. Permanently fix the brackets together using the socket head bolts
and nuts supplied.
Make sure to use spring washers.
2.5.2 Mount to a pole
In large open areas, Emerson recommends mounting the detector on a pole
to take advantage of the large omni-directional detection coverage.
Mount the detector 10 to 16 ft. (3 to 5 m) high to eliminate reflections and
ground absorption. You may mount the detector lower than 10 ft. (3 m), but
coverage may be reduced; contact an Emerson representative for details.
Make sure the pole complies with local standards and is capable of
supporting the detector weight at the installation height, taking
environmental factors into consideration.
Attach the detector to the pole using two U-bolts fixed to the pole mounting
adapter (you can use the wall bracket for pole mounting if the pole is 1.5 to
2-in. (38.1 to 50.8 mm) diameter. Emerson suggests torquing to 45 Nm, but
use local standards in the first instance.
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Figure 2-5: Pole Mounting Diagram
A. See Step 1.
B. See Step 2.
C. See Step 3.
D. Floor
E. Vertical mounting locking fastener
F. Roof
G. Pole mounting adapter
Note
Specify U-bolt and pole mounting adapter size at time of order. Standard
parts are available for tube sizes from Ø 1.5 in. (38.1 mm) to 4 in. (101.6
mm).
Weight of detector is 40 lb. (18 kg) approximately. Specify free-standing
pole size to support the detector to local standards. Ensure calculations
employ suitable civic factor of safety to support extended weight at
detection height. Ensure nyloc fixing nuts are tightened to 45 Nm or to
applicable local standards.
Procedure
1. Attach pole mounting adapter to pole using two M10 U-bolts. Secure
using nyloc nuts and/or spring washers.
2. Position the detector so that the standard bracket is on the studs of
the pole adapter. Secure the brackets together using the two M10
nuts provided.
3. Permanently fix the brackets together using the socket head bolts
and nuts supplied.
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Use spring washers.
2.5.3 Mount DNV certified detector
When an installation requires equipment to be DNV certified, you must
mount the detector using a DNV mounting bracket.
Figure 2-6: DNV Mounting Diagram
A. Roof
B. Detector permanently locked in vertical position by 4X M10 bolts (one
either side and two on underside of bracket)
C. Floor
D. See Step 3.
E. See Step 2.
F. See Step 1.
G. DNV mounting bracket: GDU-02-412
Figure 2-6 shows the mounting arrangement for DNV installation. Torque all
bolts to 45 Nm and use spring washers in all cases.
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Figure 2-7: DNV Mounting Drilling Template
Figure 2-7 shows the position of the mounting slots on the DNV mounting
bracket supplied with the DNV detector. Drill pairs of Ø 0.4-in. (10 mm)
holes between 2.8 in. (70 mm) and 3.5 in. (90 mm) apart, with a vertical
distance of 3 in. (75 mm) between the two pairs of holes.
Procedure
1. Attach DNV mounting bracket directly to wall or flat horizontal
support using 4 M10 bolts as shown.
Use spring washers.
2. Rest the detector on the flat base plate of the DNV bracket and
secure using M10 bolts either side, making sure to use spring
washers.
3. Secure the detector to the base plate using two M10 bolts, making
sure to use spring washers.
2.6
Terminal compartment wiring
WARNING
Failure to follow these installation guidelines could result in death or serious
injury.
Ensure that only qualified personnel install the detector.
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WARNING
Electrical shock could cause death or serious injury.
Use extreme caution when making contact with the leads and terminals.
Do not open the detector's enclosure in a classified area or where an
explosive atmosphere may be present unless the power to the detector
has been removed.
The detector's terminal cover is certified to flameproof standards; do not
open it while energized.
NOTICE
Connect the detector housing to local ground via the external earth point as
shown in Figure 2-12. Make sure the ground wire is a minimum of 4 mm2 (8
AWG) and as short as possible. Make sure termination at the detector is
suitable for M6 (0.25-in.) fastener. Ensure earth wire is attached using the
supplied spring washer.
The standard GDU-Incus is temperature rated between -40 and +185 °F (-40
and +85 °C), and the heated variant is temperature rated between -67 and
+185 °F (-55 and +85 °C). Ensure that all cable is rated to the appropriate
temperature of installation.
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2.6.1 Wire the detector
NOTICE
Wiring codes and regulations may vary. Wiring must comply with all
applicable regulations relating to the installation of electrical equipment in a
hazardous area and is the installer's responsibility. If in doubt, consult a
qualified official before wiring the system.
In applications where wiring is installed in a conduit, do not use the conduit
for wiring to other equipment.
For full EMC requirements, ensure incoming cables are threaded through the
ferrite beads (provided with the detector). See Figure 2-8.
Figure 2-8: Ferrite Bead Locations
A. Thread cable through ferrite
B. Ferrite
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Procedure
1. To gain access to the terminal compartment, undo the six terminal
cover fixing screws and raise the terminal cover vertically until clear
of the main enclosure.
The terminal cover is held in place with a stainless steel wire. You can
lower the terminal cover to the side of the detector during
installation, but take care to ensure the flame path is not damaged.
Refer to Figure 2-9 for the flamepath details.
Figure 2-9: Flame Path Details
A. Terminal cover
B. Flame path
C. O-ring
2. Seal the terminal compartment with two O-rings to prevent water
ingress.
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Before closing, Emerson recommends visually inspecting the
detector to ensure the O-rings are in place and undamaged. Also
check the flame paths of the terminal cover and main enclosure for
signs of damage. See Figure 2-9 for O-ring and flame path positions.
3. Connect cable shield to instrument earth in the control room only
unless extra radio frequency interference (RFI) protection is required
and all local and site grounding regulations are met, in which case,
terminate the shield to local ground via one of the internal earth
points shown in Figure 2-10.
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Figure 2-10: GDU-Incus Terminal Compartment Diagram
A. Customer cable entry position 1
B. M4 internal earth point for use with multiple cable entry
C. Ferrite supplied in box
D. Terminal row 1
E. Terminal board
F. Terminal row 2
G. M4 internal earth point for use with multiple cable entry
H. Customer cable entry position 2 (not available for FM certified
detectors)
Figure 2-10 shows a view of the GDU-Incus with the terminal cover
removed. For single entry enclosures, enter customer cable via
position 1; use positions 1 and 2 for dual entry enclosures.
The terminals are separated into power and communications for
terminal row 1 and relay outputs for terminal row 2.
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4. Tighten the six terminal cover fixing screws to a torque of 9 Nm.
WARNING
Ensure cable entry is via suitable hazardous area approved and
ingress protection certified cable glands (customer supplied) or
conduit.
The ATEX/IECEx approved GDU-Incus has two positions for M20
cable glands, while the FM approved detector has one position
for ¾-in. national pipe thread (NPT) conduit.
Fit cable glands and conduit in accordance with manufacturers'
instructions for assembly to a certified flame-proof enclosure.
Seal all unused cable entries with a flame-proof certified plugging
device.
Ensure all cable gland and plugging devices are ingress protected
to the same standard as the enclosure to maintain certification
and are suitable for the size of the cable used.
If the detector is to be installed in an ATEX Zone 1 Hazardous
Area, use an Exd barrier seal.
Seal all FM approved detectors (US and Canada) within 18 in.
(457.2 mm) of enclosure entry using a suitably rated conduit seal.
NOTICE
The terminal cover label specifies thread size for cable entry.
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2.6.2 Wiring configurations
Figure 2-11: Electrical Connection Drawing
A. Terminal row 1
B. Terminal row 2
Table 2-1: Terminal Row 1
Symbol Description
Single cable entry internal earth
0V 24 V return - (0 V)
+24v +24 Vdc (15 to 30 Vdc)
mA 4-20 mA output
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Table 2-2: Terminal Row 2
Abbreviation Description
F NO Fault relay normally open
F NC Fault relay normally closed
F C Fault relay circuit contact
A1 NO Alarm 1 normally open
A1 NC Alarm 1 normally closed
A1 C Alarm 1 circuit contact
485+ Factory use only
485- Factory use only
F1 Factory use only
F2 Factory use only
Refer to Table 2-1 and Table 2-2 for descriptions of the cable entries for
terminal rows 1 and 2.
According to standard, connect three-wire connection cables to Terminal
Row 1 in positions +24 v, 0 V, and current loop output connected to the mA
terminal. The maximum loop resistance is 500 Ω.
Current source is the standard default operation; current sink is an option
you should specify when you order.
Relay data: 1.4 A, 30 Vdc switch voltage.
Related information
Relay options
2.7
External cables
WARNING
Choose customer cable in accordance with hazardous area certification
and applicable local regulations.
The GDU-Incus has a temperature rating of 185 °F (85 °C). When used in
areas with an ambient temperature above 140 °F (60 °C), ensure cable
has a rating that is equal to or exceeds the proposed maximum working
temperature.
The following data indicates maximum cable length restriction due to
voltage drop based on a nominal input voltage of 24 Vdc.
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Conductor cross
sectional area/gauge
0.5 mm2, 20 AWG 1770 ft. (540 m) 240 ft. (75 m)
1.0 mm2, 18 AWG 2800 ft. (855 m) 380 ft. (115 m)
1.5 mm2, 16 AWG 4470 ft. (1360 m) 620 ft. (185 m)
2.5 mm2, 14 AWG 7120 ft. (2170 m) 990 ft. (300 m)
2.8 External ground
Connect the detector housing to local ground via the external earth point as
shown in Figure 2-12.
Figure 2-12: External Grounding Point
Maximum cable length
for standard, non-heated
GDU-Incus
Maximum cable length
for heated GDU-Incus
A. Terminal cover in open position
B. Terminal cover restraint
C. M6 external earth point
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2.9 Commissioning
2.9.1 Visual inspection
Before powering the detector, inspect the following:
Refer to Figure 2-13 for key locations on the GDU-Incus when completing
this inspection.
Figure 2-13: Components of the GDU-Incus
A. Display
B. Sensor (four positions)
C. Sensor pod (four positions)
D. Mounting bracket
E. Enclosure mounting point
F. Terminal cover bolts (six positions). Tighten to 9 Nm.
G. Terminal cover
H. External earth point
I. Main enclosure bolts (six positions). Do not remove or adjust.
• Ensure detector is correctly situated for area of detection.
• Ensure mounting bracket is secured to mounting points on the detector
and mounting surface/pole.
• Check pole mount (if present) for suitability to withstand detector
weight and measurement
• Ensure external earth is correctly attached using spring washer.
• Ensure correct cable gland installation and appropriate certification or
local regulations have been observed. Check correct cable installation in
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the terminal compartment; ensure terminal compartment flame paths
and seals are intact.
• Ensure incoming cable is threaded through ferrite beads (Figure 2-8).
• Tighten terminal cover bolts to the 9 Nm recommended torque.
• Verify main enclosure bolts are in place. Emerson torques these bolts at
the factory; do not adjust or tamper with them.
• Check display glass for damage or contaminants that may display.
• Ensure correct operating supply voltage.
2.9.2 Power up
Upon power up, a brief functionality check runs to ensure detector
functionality; this lasts no more than five seconds. Once completed, the
detector goes into normal operation using the factory/customer defaults
specified at time of order or signals any faults that may be present.
In addition, the display shows the real-time ultrasonic sound level, the
detector becomes responsive to commands for function setup via hand-held
TREX or AMS, and all relays are energized or de-energized as per defaults.
Note
If Emerson has set the detector at the factory for specific site requirements,
Emerson recommends carrying out the steps in Check sensor functionality
before you finish commissioning.
Related information
Fault outputs
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3 Operation
3.1 Normal operation
On power-up, the detector initializes a diagnostic check and then enters
normal operation mode as per factory default settings.
Factory operation mode 71 settings
• 4-20 mA = 4-120 dB (linear scale factor).
• Relays are energized open; loss of power causes alarm (fail-safe).
• Relays are set to non-latching.
• Reset alarms enabled; allows latched relays to be reset and restarts alarm
delay.
• Alarm level set to 70 dB for relay output.
• Delay time set to 15 seconds for relay output.
• All communication ports are active and ready to receive commands.
3.1.1 Alarm level
The alarm level is the ultrasonic sound level at which an alarm state is
triggered. During the alarm state, the display flashes, the relays switch
states, and the current loop becomes active if one or more sensors were in
fault mode (if no sensors are in fault, the current loop will already be
outputting dB level).
To avoid false alarms, Emerson recommends setting the alarm level above
the background level established by mapping when all processes are
operational. If you don't know the background level, Emerson recommends
using the detector to analyze the background. Take care to observe all
processes that may cause intermittent ultrasonic noise, such as pressure
relief valves.
Contact an Emerson representative for advice on alarm levels.
Note
The higher the alarm level, the smaller the detector coverage radius; it is
therefore important to establish a safe alarm level at the lowest permissible
rate.
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Figure 3-1: Suggested Alarm Levels
A. Alarm level (dB), 6 dB above background sound level
B. Background sound level (dB)
Figure 3-1 shows the suggested alarm level settings (6 dB above background
sound level) for known background sound levels. The values shown have
been found to provide sufficient immunity against most spurious alarms;
however, take care to survey the area of installation for potential spurious
noise.
If you don't know background levels, use typical historical process
background levels along with a safety factor. Contact an Emerson
representative for historical values and guidance.
You can set alarm levels in the detector (via HART®/TREX/AMS) or at the
control panel. Most installations set the alarm levels in the control system.
However, please note that the best practice is to have the control panel and
the GDU-Incus's internal alarm level to always mirror each other. The reason
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for this is when the detector is in a sensor fault condition, the detector's mA
output will be a constant 2 mA and will not change to the real time mA
output (which can be converted to real-time dB) until the device's internally
set alarm level is reached or exceeded.
For example, assume a sensor fault is present and the detector's internal
alarm level is set at 70 dB. The detector's mA output will be 2 mA until the
real time dB level meets or exceeds 70 dB, at which point the detector's mA
output will change to the mA value that coincides with the real-time 70 db
level the detector is sensing.
Lastly, the display on the detector will read the real time dB values at all
times, regardless of the mA loop output.
3.1.2 Delay time
To avoid spurious alarms, Emerson recommends using a delay time for nontoxic gas applications or when instantaneous detection is not required. The
delay timer is activated from the point at which the alarm threshold is first
exceeded.
If ultrasonic noise drops below the alarm level threshold, the delay time is
reset as shown in Figure 3-3. If the ultrasonic noise level remains above the
alarm level threshold for the duration of the delay time, the alarm is
activated as shown in Figure 3-2.
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Figure 3-2: Graph Showing Alarm Activation with Leak
A. Ultrasonic sound level
B. Time duration (seconds)
C. Delay time (30 seconds)
D. Delay reached - alarm
E. Delay start point
F. Ultrasonic noise level
G. Background noise level
H. Alarm level
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Figure 3-3: Graph Showing No Alarm Activation with Spurious Noise
A. Ulstrasonic sound level
B. Delay start point
C. Noise 1
D. Alarm dB exceeded
E. Delay reset
F. Delay start point
G. Delay reset
H. Noise 2
I. Delay time (30 seconds)
J. Noise 3
K. Delay start point
L. Delay reset
M. Alarm level
N. Background noise level
In Figure 3-3, noises 1 and 2 are spurious noise spikes of approximately 1.5
seconds, typical of man-made ultrasonic noise produced through normal
maintenance procedures. Noise 3 is a longer spurious noise of approximately
13 seconds, typical of a pressure relief valve. Delay time is introduced to
ignore spurious noise spikes, as the detector will reset when noise level
drops below alarm level before the delay time is reached.
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Figure 3-4: Graph Showing Alarm Activation with Spurious Noise and
Leak
A. Ultrasonic sound level
B. Time duration (seconds)
C. Delay time (30 seconds)
D. Delay reached - alarm
E. Noise 1
F. Noise 2
G. Delay start point
H. Alarm level
I. Background noise level
Figure 3-4 shows detector response when a leak is encountered during a
spurious noise spike, such as a pressure relief valve. Noise 1 represents a
pressure relief valve actuating for approximately 13 seconds before a leak
(noise 2) occurs. The detector starts the delay time when the pressure relief
valve opens and continues to monitor for leaks. If a leak occurs during a
spurious noise spike, the delay time is reduced by the duration of the
spurious noise spike.
It is important to identify all spurious noise spikes of significant duration
within the detector coverage. Emerson recommends setting the alarm delay
to a value greater than the maximum spurious noise spike operating
duration. If two or more spurious noise sources are situated within the
detector coverage area, Emerson recommends assessing whether activation
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of these sources can overlap in time, in which case you should extend the
delay time accordingly.
The factory alarm delay value is set at 15 seconds. To modify this value,
connect to the GDU-Incus with a hand-held TREX device or AMS. Please note
when changing the alarm delay that setting values 0 to 99 are in 10 second
increments and 100 to 127 are in 1 second increments. 0 and 100 represent
instantaneous alarms. For example, 1 represents a 10 second alarm delay,
and 99 represents a 990 second alarm delay; whereas 101 represents a 1
second alarm delay, and 127 represents a 27 second alarm delay. Therefore,
the factory alarm delay value for 15 seconds would be 115. See Table 3-1 for
more information.
Table 3-1: Alarm Delays
Desired alarm delay value Actual input value in TREX/AMS
15 seconds (factory default) 115
10 1 or 110
30 3
60 6
0 0 or 100
3.1.3 Automatic self-test
The automatic self-test checks the complete detector every 320
milliseconds by sending an electrical signal of known amplitude through the
sensing circuitry and analyzing the result, without interrupting the normal
functionality of the sensor.
If drift, component failure, or damage occurs, the automatic self-test signals
a fault.
Related information
Fault outputs
3.2
Check sensor functionality
Emerson calibrates the sensors on the GDU-Incus at the factory; they do not
need to be adjusted. Before operation, Emerson recommends functionality
checks to ensure correct installation. On power-up, the detector performs a
diagnostic check to ensure all main functions are operational and
continuously monitors the sensors via the built-in self-test.
The sensor's functionality can be verified using the GDU-01-TT Ultrasonic
Test Transmitter and the following procedure:
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1. Ensure that the background ultrasonic level is suitable for the
distance of the proposed transmitter test.
2. Aim the transmitter at the sensor face from a known distance. The
detector's display dB level will rise according to the hand-held device
used and the distance.
3. Check all four sensors, if possible, by moving around the detector
and repeating.
3.3 Output options
The GDU-Incus comes with the following industry-standard forms of
communication:
• Analog (4-20 mA)
• HART® communication protocol
• Two configured relays
This enables the detector to be operated as part of a system, as a standalone
unit, or hard wire linked to form a sub network.
3.3.1 Relay options
The GDU-Incus has two relays configured as follows for the standard factory
default:
Table 3-2: Relay Defaults
Relay Type Factory default setting
1 Fault Energized in normal operating condition,
2 Alarm Energized in normal operating condition,
de-energized in fault condition, nonlatching
de-energized in fault condition, nonlatching
Table 3-3: Relay Data
Maximum switching current 1.4 A
Maximum switching voltage 30 Vdc
You can change relay configuration to suit installation requirements with the
user changeable functions; options include normally open/normally closed
condition and latching/non-latching.
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3.4 Display
The GDU-Incus incorporates a five-digit segment, 0.31-in. high x 0.16-in.
wide (8 mm high x 4 mm wide) character light-emitting diode (LED) display
with red numerals as standard.
During operation, the real-time dB level is continuously shown while below
the programmed alarm level and flashing when above the programmed
alarm level.
Figure 3-5: Example of Real-Time dB Level Display: 53 db
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3.5 4-20 mA output
Figure 3-6: 4-20 mA Output Values (Example Shows Default Op-Mode
71)
A. Normal operation
B. Detector fault detected
C. 100 percent of range
D. Linear scale
E. 0 percent of range
F. 2.0 mA sensor head test fault
(1)
G. 1.0 mA internal process fault
H. 0.5 mA all sensor heads failed
(1) The GDU-Incus is providing coverage when the 2.0 mA sensor test fault is active.
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I. 0 mA major fault
Figure 3-6 shows the 4-20 mA output values for the detector during normal
operation and under various fault conditions. The value on the left side
shows the mA output tolerance band; internal fault is set for a 1.0 mA output
with a tolerance of 0.8 to 1.2 mA, for example.
All mA outputs are grouped in descending order to signify importance and
to allow for instant status recognition.
Normal operation between 4 to 20 mA (±0.2 mA): detector working, no fault
conditions.
Related information
2.0 mA sensor test fault
Fault outputs
3.6 Fault outputs
3.6.1 2.0 mA sensor test fault
One or more sensor heads fail to respond with the correct value during the
automatic self-test.
Output is continuous at 2.0 mA unless the test is subsequently passed
successfully or an alarm condition occurs, in which case the normal sound
level is transmitted on the current loop.
Related information
Alarm level
3.6.2 1.0 mA internal process fault
Continuous 1.0 mA (±0.2 mA) output for any known internal or external
faults that include over-voltage, high/low external voltage, blown fuse, or
high/low internal voltage.
3.6.3 0.5 mA all sensors dead fault
Continuous 0.5 mA (±0.2 mA) output, indicating that all four sensors have
failed self-test. Firmware version 3.4 onwards.
Recommended action
Contact your Emerson representative.
3.6.4 Zero mA major fault
Zero (0) mA output is either caused by a total loss of power to the detector
or a serious microprocessor fault.
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Potential cause
Loss of power.
Recommended action
Apply power to the detector.
Potential cause
Serious microprocessor fault.
Recommended action
Contact your Emerson representative.
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4 HART® functionality
The GDU-Incus has HART communication enabled by default. The HART
communication mode is standard current output FSK, to HART protocol
revision number 7.
The device reports the primary variable (PV) measurement of sound
pressure level in units of dB. The secondary variable (SV) reports the internal
case temperature (degrees Celsius) of the detector. The tertiary variable
(TV) reports the temperature of the heated section of the detector if the
heater option is fitted; otherwise, it will report the same data as the
secondary variable.
A device driver (DD) file for Emerson AMS and the hand-held TREX field
terminals is available from Emerson. In addition, you can use the detector
with FDT frame applications using a generic DTM with limited functionality.
The Incus HART Field Device Specification provides full technical details of
the HART interface.
Note
1. The detector does not support the delayed-response mechanism,
burst-mode, or write protection.
2. The HART device parameters Tag and Long Tag are set to INCUS and
GDU-02-INCUS by default. If unique identification is required, set up
the parameters on site.
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5 Product certifications
Rev 0.1
5.1 Ordinary location certification
As standard, the transmitter has been examined and tested to determine
that the design meets the basic electrical, mechanical, and fire protection
requirements by FM Approvals, a nationally recognized test laboratory
(NRTL) as accredited by the Federal Occupational Safety and Health
Administration (OSHA).
5.2 Installing equipment in North America
The US National Electrical Code® (NEC) and the Canadian Electrical Code
(CEC) permit the use of Division marked equipment in Zones and Zone
marked equipment in Divisions. The markings must be suitable for the area
classification, gas, and temperature class. This information is clearly defined
in the respective codes.
5.3 USA
FM
Explosionproof with Intrinsically Safe sensors
Flameproof with Intrinsically Safe sensors
Certificate
Standards
Markings
3043275
FM Class 3600: 2011, FM Class 3610: 2010, FM Class 3615:
2006, FM Class 3810: 2005, ANSI/NEMA 250: 1991, ANSI/ISA
60079-0: 2009, ANSI/ISA 60079-1: 2009, ANSI/ISA 60079-11:
2011
Class 1, Div 1, Groups B,C, and D, T4
AEx d ib Class 1, Zone 1, Group IIB+H2, T4
Type 4X
-40 °F (-40 °C) to 185 °F (85 °C)
5.4 Canada
FM
Explosionproof with Intrinsically Safe sensors
Flameproof with Intrinsically Safe sensors
Certificate
42 Emerson.com
3043275C
August 2021 Quick Start Guide
Standards
Markings
5.5 Europe
Intertek
Intrinsically Safe and Explosionproof/Flameproof
Certificate
Standards
Markings
Special Conditions for Safe Use (X)
1. As flameproof joint lengths exceed the relevant minimum
FM Class 3600: 2011, FM Class 3610: 2010, FM Class 3615:
2006, FM Class 3810: 2005, ANSI/NEMA 250: 1991, ANSI/ISA
60079-0: 2009, ANSI/ISA 60079-1: 2009, ANSI/ISA 60079-11:
2011
Class 1, Div 1, Groups B,C, and D, T4
Ex d ib Class 1, Zone 1, Group IIB+H2, T4
Type 4X
-40 °F (-40 °C) to 185 °F (85 °C)
ITS09ATEX1683X
EN IEC 60079-0: 2018, EN 60079-1: 2014, EN 60079-11: 2012
II 2 G Ex db ib IIB+H2 T4 Gb
Model Option: -A
-40 °F (-40 °C) ≤ Ta ≤185 °F (85 °C)
Model Option: -B
-67 °F (-55 °C) ≤ Ta ≤ 185 °F (85 °C)
dimensions given in IEC 60079-1: 2014 Clauses 5.2 to 5.5,
information on the dimensions of the flameproof joints shall be
obtained from the listed certified schedule drawings; contact the
manufacturer.
2. When temperature at the cable entry could exceed 158 °F (70 °C) or
176 °F (80 °C) at the branching point, suitably rated cable must be
selected based on the T-Class/T max.
3. Minimum fastener yield stress required ≥ 450 Moa (property class
A4-70).
5.6
Quick Start Guide 43
International
IECEx
Certificate
Standards
IECEXITS10.0004X
IEC 60079-0: 2017, IEC 60079-1: 2014-06, IEC 60079-11:
2011
Quick Start Guide August 2021
Markings
Special Conditions for Safe Use (X)
1. As flameproof joint lengths exceed the relevant minimum
2. When temperature at the cable entry could exceed 158 °F (70 °C) or
3. Minimum fastener yield stress required ≥ 450 Moa (property class
5.7 Brazil
Inmetro
Intrinsically Safe and Explosionproof/Flameproof
Certificate
Standards
Markings
T amb XX °C to 185 °F (85 °C)
XX is -67 °F (-55 °C) when fitted with heating device
XX is -40 °F (-40 °C) when no heating device is fitted
IECEx ITS 10.0004X
dimensions given in IEC 60079-1: 2014 Clauses 5.2 to 5.5,
information on the dimensions of the flameproof joints shall be
obtained from the listed certified schedule drawings; contact the
manufacturer.
176 °F (80 °C) at the branching point, suitably rated cable must be
selected based on the T-Class/T max.
A4-70).
UL-BR 15.0063X
ABNT NBR IEC 60079-0: 2008 + Errata 1: 2011
ABNT NBR IEC 60079-1: 2009 + Errata 1: 2011
ABNT NBR IEC 60079-11: 2009
Ex db ib IIB+H2 T4 Gb
(2)
≤ Ta ≤ 185 °F (85 °C)
Special Conditions for Safe Use (X)
1. No modifications must be made to the flamepaths of the unit
without consultation of the drawings listed in ExTR cover sheets.
2. When temperature at the cable entry could exceed 158 °F (70 °C) or
176 °F (80 °C) at the branching point, suitably rated cable must be
selected based on the T-Class/T max.
3. Minimum fastener yield stress required ≥ 450 Moa (property class
A4-70).
4. Suitably approved cable glands only to be used.
(2)
-67 °F (-55 °C) when fitted with heating device. -40 °F (-40 °C) when no heating
device is fitted.
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August 2021 Quick Start Guide
5. Any unused entries must be blanked using suitably approved
blanking plugs.
6. As flameproof joint lengths exceed the relevant minimum
dimensions given in ABNT NBR IEC 60079-1: 2009, information on
the dimensions of the flameproof joints shall be obtained from the
listed certified schedule drawings; contact the manufacturer.
5.8 Republic of Korea
Explosionproof/Flameproof with Intrinsically Safe output
5.9
Certificate
Markings
Special Conditions for Safe Use (X)
1. As flameproof joint lengths exceed the relevant minimum
dimensions given in IEC 60079-1: 2014 Clauses 5.2 to 5.5,
information on the dimensions of the flameproof joints shall be
obtained from the listed certified schedule drawings; contact the
manufacturer.
2. When temperature at the cable entry could exceed 158 °F (70 °C) or
176 °F (80 °C) at the branching point, suitably rated cable must be
selected based on the T-Class/T max.
3. Minimum fastener yield stress required ≥ 450 Moa (property class
A4-70).
21-KA4BO-0134X
Ex db ib IIB+H2 T4 Gb
Additional certifications
SBS
American Bureau of Shipping (ABS) Type Approval
Certificate
Intended use
18-1744209-1-PDA
Marine and offshore applications.
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5.10 Declaration of Conformity
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5.11 China RoHS tables
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Quick Start Guide 51
*00825-0100-3003*
00825-0100-3003, Rev. AA
Quick Start Guide
August 2021
For more information:
©
2021 Emerson. All rights reserved.
Emerson Terms and Conditions of Sale are
available upon request. The Emerson logo
is a trademark and service mark of
Emerson Electric Co. Rosemount is a mark
of one of the Emerson family of
companies. All other marks are the
property of their respective owners.
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