Emerson Rosemount 935 User manual

Quick Start Guide
00825-0100-4035, Rev AA
April 2021
Rosemount™ 935
Open Path Combustible Gas Detector

Legal notice
The Rosemount system described in this document is the property of Emerson.
No part of the hardware, software, or documentation may be reproduced, transmitted, transcribed,
stored in a retrieval system, or translated into any language or computer language in any form or by
any means without prior written permission of Emerson.
While great efforts have been made to ensure the accuracy and clarity of this document, Emerson
assumes no responsibility resulting from any omissions in this document or from misuse of the
information obtained herein. The information in this document has been carefully checked and is
believed to be entirely reliable with all the necessary information included. Emerson does not assume
any liability arising out of the application or any use of any product or circuit described herein; neither
does it convey license under its patent rights or the rights of others.
WARNING
All individuals who have or will have responsibility for using, maintaining, or servicing the product must
read this manual thoroughly.
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.
CAUTION
The source and detector are not field-repairable due to the meticulous alignment and calibration of the
sensors and the respective circuits.
Do not attempt to modify or repair the internal circuits or change their settings, as this will impair the
system's performance and void the Emerson product warranty.
Glossary and abbreviations
Abbreviation Meaning
Analog video Video values are represented by a scaled signal.
ATEX Atmosphere explosives
AWG American wire gauge
BIT Built-in test
CMOS Complementary metal oxide semiconductor image sensor
Digital video Each component is represented by a number representing a discrete quantization.
DSP Digital signal processing
EMC Electromagnetic compatibility
EMI Electromagnetic interference
EOL End of line
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Abbreviation Meaning
FOV Field of view
HART®Highway addressable remote transducer communication protocol
IAD Immune at any distance
IECEx International Electrochemical Commission explosion
IP Internet protocol
IPA Isopropyl alcohol
IR Infrared
IR3 Refers to the three infrared sensors
JP5 Jet fuel
Latching Refers to relays remaining in the On state even after the On condition has been removed.
LED Light-emitting diode
LEL Lower explosive limit: The minimum concentration of a substance (gas/vapor) in air mixture
that can be ignited. This mixture is different for every gas/vapor, measured in % of LEL.
LEL.m Integral of concentration in LEL units (1 LEL = 100% LEL) and the operation distance in meters
(m).
LNG Liquified natural gas
LPG Liquified petroleum gas
mA MilliAmps (0.001 amps)
Modbus®Master-slave messaging structure
N.C. Normally closed
N.O. Normally open
N/A Not applicable
NFPA National Fire Protection Association
NPT National pipe thread
NTSC National Television System Committee (a color encoding system)
PAL Phase alternation by line (a color encoding system)
PN Part number
RFI Radio frequency interference
RTSP Real time streaming protocol
SIL Safety integrity level
UNC Unified coarse thread
Vac Volts alternating current
Vdc Volts direct current
µm Micrometer
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Contents
Installation................................................................................................................................... 5
Operation...................................................................................................................................22
Product certifications................................................................................................................. 29
Wiring configurations.................................................................................................................30
Declaration of Conformity..........................................................................................................36
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1 Installation
1.1 General considerations
1.1.1 Personnel
Only employ suitably qualified personnel who are familiar with the local
codes and practices and trained for gas detection maintenance.
Ensure that wiring is only performed and supervised by someone with
knowledge of electronics and, in particular, wiring installation.
1.1.2 Site requirements
When installing the Rosemount 935, take into account the weight of the
monitored gas compared to that of the surrounding air and the individual
site requirements.
Ensure that the site selected gives the detector a direct view to the source.
The mounting point for each item should be secure and stable with minimal
vibrations. Mount the equipment in a position where it cannot be knocked
out of alignment and is guarded from physical impact.
1.1.3 Source and detector
Select the appropriate detector for the length of open path to be monitored.
To allow for aging of the source and a reduction of the infrared signal due to
adverse weather, Emerson recommends using a detector that is not at the
limit of its operating range.
The general recommendation is to install the detector at a distance from the
source of not more than 75 percent of the specified operating distance. In
severe weather conditions, such as offshore oil production and exploration,
reduce this distance to 50 percent.
Keep the open path between the source and detector clear of any obstacles
that might hinder the free movement of air in the protected area or block
the infrared beam.
1.1.4 Tips for gas detector locations
To provide the best detection coverage, install the detector:
•Below potential leak source for gases heavier than air.
•Above potential leak sources for gases lighter than air.
•Near to leak sources along the expected leak trajectory, taking into
account prevailing wind directions.
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CAUTION
For optimal performance, avoid placing the detector in locations frequently
covered by steam.
1.1.5 Separation distances
To avoid cross talk between adjacent Open Path Gas Detector (OPGD)
systems where transmitters are installed on the same side, keep the relevant
separation distance between the neighboring OPGD systems according to
the installation lengths as listed in Table 1-1.
Table 1-1: Minimum Separation Distances
Installation line of sight distance, ft.
(m)
Minimum separation, ft. (m)
33 (10) 3.3 (1)
66 (20) 5 (1.5)
98 (30) 6.5 (2.5)
131 (40) 11.5 (3.5)
164 (50) 15 (4.5)
197 (60) 16.5 (5)
230 (70) 20 (6)
262 (80) 23 (7)
295 (90) 26 (8)
328 (100) 28 (8.5)
361 (110) 29.5 (9)
394 (120) 33 (10)
427 (130) 34.5 (10.5)
459 (140) 38 (11.5)
492 (150) 42.5 (13)
525 (160) 47.5 (14.5)
558 (170) 49 (15)
591 (180) 51 (15.5)
623 (190) 52.5 (16)
656 (200) 54 (16.5)
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1.1.6 Wiring
For wiring, use color-coded conductors or suitable wire markings or labels.
•The wire cross-section must be between 28 to 14 AWG (0.5 mm2 to
2.5 mm2).
•The selected wire gauge should be based on the number of detectors
used on the same loop and the distance from the control unit. The
maximum number of wire connections in one terminal is two wire cross-
sections, each 1 mm2.
•To fully comply with electromagnetic compatibility (EMC) directive and
protect against interference caused by radio frequency interference (RFI)
and electromagnetic interference (EMI), the cable to the detector must
be shielded, and the detector must be grounded. Ground the shield at
the detector end.
1.2 Preparations for installation
Ensure that installation complies with local, national, and international
regulations and norms as applicable to gas detectors and approved electrical
devices installed in hazardous areas.
1.2.1 Equipment
The system should include the following (in addition to the Quick Start
Guide):
Figure 1-1: Box Contents
Commissioning kit (not pictured)
A. Source or detector (per box)
B. Tilt mounts
•Detector unit: 935-R1F00XXXX
•Source unit: 935-TXFXXXXXX
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•Two tilt mount bases (one for the source and one for the detector).(1)
•Commissioning kit, three options when ordered:
—For methane calibration
—For propane calibration
—For ethylene calibration
The commissioning kit includes:
•Alignment tool kit
•Function check filters
•HART® hand-held harness kit
Other accessories are available (per customer request):
•5-in. pole mount kit
•2 to 3-in. pole mount
•Wall mount
•Protective cover
Note
See the Rosemount 935 Product Data Sheet for accessory part numbers.
1.2.2 Required tools
You can install the detector using general purpose common tools and
equipment.
Table 1-2: Tools
Tool Function
Alignment kit Provides tools to install fine alignment tool.
Hex key 8 mm Mounts the detector on the tilt mount.
Hex key 3/16 in. Aligns the detector.
Hex key 5/16 in. Screws ¾ stop plug.
Flat screwdriver 4 mm Connects ground terminal.
Flat screwdriver 2.5 mm Connects wires to the terminal block.
(1) If you order a source or detector separately, you will receive one tilt mount.
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1.3 Certification instructions
WARNING
EXPLOSION
Do not open the detector, even when isolated, in a flammable atmosphere.
•The cable entry point may exceed 182 °F (83 °C). Take suitable
precautions when selecting the cable.
•The equipment may be used with flammable gases and vapors with
apparatus groups IIA and IIB+H2 T4 in the ambient temperature range:
-67 to +149 °F (-55 to +65 °C).
•Only suitably trained personnel shall install the detector in accordance
with the applicable code of practice, e.g., EN 60079-14: 1997.
•Only suitably trained personnel shall inspect and maintain this
equipment in accordance with the applicable code of practice, e.g., EN
60079-19.
•Only suitably trained personnel shall repair this equipment in accordance
with the applicable code of practice, e.g., EN 60079-19.
•The certification of this equipment relies upon the following materials
used in its construction:
—Enclosure: Stainless steel 316
—Windows: sapphire glass
—Seals: EPDM
•If the equipment is likely to come into contact with aggressive
substances, then it is your responsibility to take suitable precautions that
prevent it from being adversely affected, thus ensuring that the type of
protection provided by the equipment is not compromised.
—Aggressive substances: For example, acidic liquids or gases that may
attack metal or solvents that may affect polymeric materials.
—Suitable precautions: For example, regular checks as part of routine
inspections or establishing from the material's safety data sheets that
it is resistant to specific chemicals.
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1.4 Special conditions for safe use from ATEX IECEx
certificate
The dimensions of the flameproof joints differ from the relevant minimum
or maximum values required by Table 2 of IEC/EN 60079-1: 2007 for IIB + H2,
as detailed in Table 1-3.
Table 1-3: Flamepaths
Flamepath
description
Type of joint Minimum width "L"
in inches
(millimeters)
Maximum gap "ic" in
inches (millimeters)
Cylindrical section of
spigot (both ends of
Ex d compartment)
Cylindrical 0.59 (15) 0.003 (0.08)
1.2-in. (30 mm)
diameter window
fitted against
enclosure
Flanged 0.42 (10.7) 0.001 (0.02)
1.6-in. (39.5 mm)
diameter window
fitted against
enclosure
Flanged 0.39 (10) 0.001 (0.02)
•Gaps, "ic", should not be modified to be any larger, and widths, "L", should
not be modified to be any shorter than the values in Table 1-3.
•Connections to the intrinsically safe (I.S.) port on the side of the detector
enclosure should be made using equipment that maintains the
intrinsically safe levels of protection.
•The Um should be installed in accordance with one of the following:
—The Um is 18 to 32 Vdc in a SELV/PELV system.
—Via a safety isolating transformer, complying with the requirements
of IEC 61588-2-6 or technically equivalent standard.
—Directly connected to apparatus, complying with IEC 60950, IEC
61010-1, or technically equivalent standard.
—Fed directly from cells or batteries.
•If the product is to be used as a safety related device, an appropriate
independent certification, would be required meeting all the
requirements.
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1.5 Install conduits and cables
The conduit and cable installation must comply with the following
guidelines:
•To avoid water condensation in the detector, install it with the conduits/
cable entries facing downwards.
•Use flexible conduits/cables for the last portion connecting to the
detector.
•When pulling the cables through the conduits, ensure that they are not
tangled or stressed. Extend the cables about 12-in. (30 cm) beyond the
detector location to accommodate wiring after installation.
•After pulling the conductor cables through the conduits, perform a
continuity test.
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1.6 Mount detector and source to tilt mount
You can install the detector and source in two ways with the same tilt mount
by using the upper or lower mounting access.
Figure 1-2: Mounting the Tilt Mount and Detector Using the Lower
Mounting Access
A. Front shield
B. Back cover
C. Security screw
D. Locating pins
E. Alternate mounting location
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Figure 1-3: Tilt Mount
A. Detector/source holding plate
B. Vertical fine alignment screw
C. Tilt mount holding plate
D. Horizontal fine alignment screw
E. Vertical crude alignment tightening screw
F. Vertical fine alignment tightening screw
G. Horizontal crude alignment tightening screw
H. Horizontal fine alignment tightening screw
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Figure 1-4: Detector and Tilt Mount Assembly Using Lower Mounting
Access
A. Back cover
B. Detector
C. Alignment tool tightening bolt
D. Alignment tool
Table 1-4: Tilt Mount Kit
Item Quantity Type / model
Tilt mount 1 N/A
Screw 1 M10 x 1.5
Spring washer 1 No. 10
Prerequisites
Prior to mounting the tilt mount to a stable surface, verify that the line of
site is unobstructed and corresponds to the detector's installation distance.
Procedure
1. Place the tilt mount holding plate in its designated location and
secure it with four fasteners through four holes with diameters of
0.3-in. (8.5 mm).
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NOTICE
Skip this step if the tilt mount is already installed.
Removing the detector for maintenance purposes does not require
removing the tilt mount.
2. Place the detector with its conduit/cable inlets pointing downwards
on the detector holding plate of the tilt mount.
3. Secure the detector with M10 x 1.5 screws with number M10 spring
washers.
4. Secure the detector to the tilt mount using hex key number 7 for
M10 x 1.5 screws.
5. Repeat steps Step 1 through Step 4 to install the source.
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1.7 Wire detector
To install the detector wiring:
Figure 1-5: Detector with Cover Removed
A. Housing
B. Internal earth connection
C. Terminal board
D. Inlet conduit
E. Detector holding plate
F. Earth terminal
G. Connection to Field Communicator
Procedure
1. Release the back cover secure bolt and open the detector back cover.
2. Remove the protective plug mounted on the detector conduit/cable
entry inlet.
3. Pull the wires through the detector inlet.
4. Use a ¾-in.-14 national pipe thread (NPT) or M25 x 1.5 explosion-
proof conduit connection/cable gland to assemble the cable/
explosion-proof conduit to the detector.
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5. Connect the wires to the required terminals according to the wiring
diagram.
See Wiring configurations.
6. Connect the grounding wire to the ground screw outside the
detector.
The detector must be well grounded to earth ground.
7. Place and secure the detector cover by screwing the cover and
securing it using the secure bolt.
1.8 Wiring to detector terminals
The detector has six wiring terminals. Table 1-5 describes the function of
each electrical terminal of the detector.
Table 1-5: Wiring Options
Terminal number Function
1 Power +24 Vdc
2 Return -24 Vdc
3 0-20 mA (input)
4 0-20 mA (output)
5 RS-485 (+)
6 RS-485 (-)
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1.9 Flash source wiring
1.9.1 Install flash source wiring
To install the wiring:
Figure 1-6: Source with Cover Removed
A. Housing
B. Internal earth connection
C. Terminal board
D. Inlet conduit
E. Detector holding plate
F. Earth terminal
Procedure
1. Release the back screw bolt and open the source back cover.
2. Remove the protective plug mounted on the source conduit/cable
entry inlet; pull the wires through the source inlet.
3. Use a ¾-in.-14 national pipe thread (NPT) or M25 x 1.5 explosion-
proof conduit connection/cable gland to assemble the cable/
explosion-proof conduit to the detector.
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4. Connect the wires to the required terminals according to the wiring
diagram.
See Wiring to source terminals and Wiring configurations.
5. Connect the grounding wire to the ground screw outside the
detector.
The source must be well grounded to earth ground.
6. Place and secure the source back cover by screwing the cover and
securing the back screw bolt.
1.9.2 Wiring to source terminals
The source contains six wiring terminals.
Table 1-6: Flash Source Wiring Options
Terminal number Function
1 Power + 24 Vdc
2 Return - 24 Vdc
3 Not used
4 Not used
5 RS-485 (+)
6 RS-485 (-)
1.10 Align detector
Use the alignment tool to perform full alignment.
Align the detector in two stages: crude alignment and fine alignment.
The alignment tool includes a periscope that consists of a prism and an
ocular located vertical to the alignment tool assembly. This allows you to
look into the opposite unit perpendicularly to the alignment when access
from the rear of the unit is impossible. For installations where rear access is
possible, you don't need to install the periscope. In this case, you can remove
it by releasing the periscope fastening screw.
NOTICE
Prior to installing the alignment tool, verify that the alignment tool and its
sight mounting are free from any dirt to ensure proper alignment according
to factory calibration.
Do not attempt to change any factory calibration at the alignment tool or its
mounting.
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To align the detector (see Figure 1-3 and Figure 1-4):
1. Make sure that the detector and flash source are installed properly.
Installation provides installation instructions.
2. Remove the front shield using the two captive screws.
3. Install the alignment tool assembly on the detector/source front.
4. Fasten the alignment tool with fastening screws.
1.10.1 Perform crude alignment
Prerequisites
Use a ¼-in. Allen screwdriver for all alignment screws.
Procedure
1. Loosen the horizontal lock screws.
2. Approximately aim the source horizontally towards the detector.
3. Tighten the horizontal lock screw adjacent to the plate.
4. Loosen the vertical lock screws.
CAUTION
If the detector is not properly supported when the lock screws are
loosened, it could fall and get damaged.
Support the detector when loosening the vertical lock screws.
5. Approximately aim the source vertically towards the detector.
6. Tighten the outer vertical lock screw.
7. Repeat this process for the detector.
1.10.2 Perform fine alignment
Refer to Figure 1-4 to see the detector with the alignment tool installed.
Procedure
1. Remove the front shield and mount the alignment tool on the front
of the source using the three screws.
The alignment tool is supplied in the commissioning kit.
2. Aim the source towards the detector within the horizontal access.
3. Aim the alignment tool to the center of the front window of the
detector or source.
4. Tighten the outer horizontal lock screw.
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