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Emerson Rosemount 935 Reference Manual

Open path combustible gas detector
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Reference Manual
00809-0100-4035, Rev AJ
May 2023
Rosemount
™
935
Open Path Combustible Gas Detector

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Summary of Contents for Emerson Rosemount 935

  • Page 1 Reference Manual 00809-0100-4035, Rev AJ May 2023 Rosemount ™ Open Path Combustible Gas Detector...
  • Page 2 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.

  • Page 3: Table Of Contents

    6.5 Conduit/cable installation......................31 6.6 Receiver/transmitter mounting....................32 6.7 Receiver wiring.......................... 32 6.8 Receiver terminal wiring......................35 6.9 Transmitter wiring........................36 Chapter 7  Operating instructions......................39 7.1 Safety operation........................39 7.2 Alignment of unit........................39 7.3 Powering up the system......................40 7.4 Safety precautions........................40 7.5 Signal verification........................41 7.6 Zero calibration..........................41 7.7 Functional check........................42 Rosemount 935...
  • Page 4 B.4 Wall mount..........................51 B.5 Commissioning kit........................51 B.6 HART handled diagnostic unit....................52 B.7 Universal RS-485 and HART IS harness kit................52 B.8 USB/RS-485 harness converter kit..................52 B.9 Protective cover.........................52 Appendix C  SIL-2 features...........................53 C.1 Safety relevant parameters..................... 53 C.2 General conditions for safe use....................53 Emerson.com/Rosemount...

  • Page 5: About This Guide

    • Wiring configurations - provides wiring diagrams for installation. • Accessories - provides a list of accessories available for the Rosemount 935 Open-Path Gas Detection System. • SIL-2 features - details the special conditions for compliance with the requirements of EN 61508 for SIL-2.

  • Page 6: Notifications

    This indicates a potentially hazardous situation that could result in serious injury and/or major damage to the equipment.  CAUTION This indicates a situation that could result in minor injury and/or damage to the equipment. Note This provides supplementary information, emphasizes a point or procedure, or gives a tip to facilitate operation. Emerson.com/Rosemount...

  • Page 7: Chapter 2 Product Overview

    The Rosemount 935 detects ambient combustible gases over a path length of up to 660 ft/200 m, even in harsh environments where dust, fog, rain, snow, or vibration can cause a high reduction of signal. The Rosemount 935 can maintain operation in up to 95% signal obscuration and ±0.5 degree of misalignment.
  • Page 8 Product overview Reference Manual May 2023 00809-0100-4035 Emerson.com/Rosemount...

  • Page 9: Chapter 3 Technical Description

    • High reliability-MTBF-minimum 100,000 hours 3.2  Applications The Rosemount 935 system is an optical control fence for combustible gases as defined in the product specification, providing perimeter monitoring and early detection in various applications, such as: • Petrochemical, pharmaceutical, and other chemical storage and production areas •...

  • Page 10: Principles Of Operation

    Statistics, ratio algorithms, data communications, diagnostics, and other functions are performed. 3.3.5  Gas sensitivity The Rosemount 935 Model uses wavelengths around the 2.3μ spectral band to measure air flammability potential between the transmitter and receiver. At this wavelength, all Emerson.com/Rosemount...
  • Page 11 The Xenon Flash transmitter was originally introduced in the first development and was designed to overcome false alarms, which were experienced by early generations of the open path system. The new Rosemount 935 employs the latest generation of flash bulbs to provide even more power and an extended operation life.

  • Page 12: Product Certification

    3.4  Product certification 3.4.1  ATEX, IECEx The Rosemount 935 is ATEX approved per SIRA 16ATEX1224X and IECEx per IECEx SIR 16.0075X per: This product is suitable for use in hazardous zones 1 and 2 with IIB+H group vapors present, and zones 21 and 22 with IIIC combustible dust types.

  • Page 13: Models And Types

    The Rosemount 935 was functional tested by FM per EN60079-29-4 and Ansi/FM 60079-29-4. 3.5  Models and types The Rosemount 935 is available in 4 models. Each model has the same receiver but a different transmitter. This allows for detection at distances of 7–200 m/∼23–656 ft. Rosemount 935...

  • Page 14: Description

    132 ft (40 m) 115 ft (35 m) 330 ft (101 m) 265 ft (81 m) 656 ft (201 m) 3.6  Description The Rosemount 935 is comprised of 2 main units: • The Flash Infrared Transmitter • The Infrared Receiver 3.6.1  Transmitter unit The transmitter unit emits a powerful IR pulse (5-10ms width) at the rate of 2 pulses per second.
  • Page 15 Figure 3-2: Receiver A. Front window section B. Label C. Main housing D. Mounting plate E. Intrinsically safe connector (RS-485/HART) F. Back cover G. Earth terminal H. Front window I. Inlet conduit J. Inlet conduit K. Indicator LED Rosemount 935...
  • Page 16 Technical description Reference Manual May 2023 00809-0100-4035 Emerson.com/Rosemount...

  • Page 17: Chapter 4 Operating Modes

    Reference Manual Operating modes 00809-0100-4035 May 2023 4  Operating modes 4.1  Operational modes The Rosemount 935 has 4 operational modes: • Normal mode • Maintenance call mode (3 mA output) • Fault mode • Zero calibration mode (1 mA output) 4.1.1 ...

  • Page 18: Visual Indicators

    Table 4-2: Transmitter LED indications Transmitter status LED color LED mode Fault Amber 4 Hz – flashing Normal Green 1 Hz – flashing 4.3  Output signals The Rosemount 935 system provides the following outputs: • 0–20 mA current output • RS-485 interface Emerson.com/Rosemount...

  • Page 19: System Setup

    Receiver configuration • Receiver default setup 4.4.1  Field configuration The Rosemount 935 incorporates several functions that can be set by the customer, using: • Host software: For additional settings and trouble shooting use the software on the product web page. •...
  • Page 20 The receiver has functions that can be programmed according to customer requirements, either at the factory or at the customer facility, using a PC software host or a handheld unit. The standard setup is as follows: Table 4-4: Receiver default setup Function Setup Gas type Methane Emerson.com/Rosemount...
  • Page 21 Front LED (Revised model with firmware number Disabled containing Py for the primary CPU and Ey for the secondary CPU) Address Table 4-5: Transmitter default setup Function Setup Heat mode Auto Heater power High Heat On temperature 5° Address Rosemount 935...
  • Page 22 Operating modes Reference Manual May 2023 00809-0100-4035 Emerson.com/Rosemount...

  • Page 23: Technical Specifications

    ± 7.5 % of the reading or ±4 % of the full scale (whichever is greater) 0.15 LEL.m Minimum detectable : -67 °F/-55 °C to +149 °F/+65 °C Temperature range: Immunity to false Does not produce a false alarm and is not influenced by alarm: • Solar radiation Rosemount 935...

  • Page 24: Electrical Specifications

    The protocol enables continuous communication between a single standard Modbus controller (master device) and a serial network of up to 247 receivers. • The protocol enables connections between different types of Spectrex receivers or other Modbus devices to the same network. Emerson.com/Rosemount...

  • Page 25: Mechanical Specifications

    Tilt mount 4.2 lb 1.9 kg 5.5  Environmental specifications The Rosemount 935 system is designed to withstand harsh environmental conditions. The transmitter and receiver units compensate for adverse conditions while maintaining accuracy. 5.5.1  High temperature The Rosemount 935 system conforms to DNVGL-CG-0339, class D.
  • Page 26 Technical specifications Reference Manual May 2023 00809-0100-4035 5.5.2  Low temperature The Rosemount 935 system conforms to DNVGL-CG-0339, class D. –67 °F/–55 °C Operating temperature: Storage temperature: –67 °F/–55 °C 5.5.3  Humidity The Rosemount 935 system conforms to DNVGL-CG-0339, class B. 5.5.4 ...

  • Page 27: Chapter 6 Installation Instructions

    The mounting point for each item should be secure and stable with minimal vibrations • Equipment should be either mounted in a position where it cannot be knocked out of alignment, or it is guarded from physical impact, above human height to avoid partial obscuration. Rosemount 935...
  • Page 28 60 (197) 5 (16.5) 70 (230) 6 (20) 80 (262) 7 (23) 90 (295) 8 (26) 100 (328) 8.5 (28) 110 (361) 9 (29.5) 120 (394) 10 (33) 130 (427) 10.5 (34.5) 140 (459) 11.5 (38) 150 (492) 13 (42.5) Emerson.com/Rosemount...

  • Page 29: Preparations For Installation

    Upon receipt of the gas detection system, check and record the following: Procedure 1. Verify that the model matches the purchase order. 2. Record the part number (P/N) and serial number of the receivers and transmitter units, and the installation date in an appropriate logbook. Rosemount 935...

  • Page 30: Certification Instructions

    — Examples of suitable precautions: routine inspections, establishing resistance to specific chemicals from the material’s data sheets. — Examples of aggressive substances: acidic liquids or gases that may attack metals, solvents that may affect polymeric materials. Emerson.com/Rosemount...

  • Page 31: Conduit/Cable Installation

    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 receiver location to accommodate wiring after installation. • After the conductor cables have been pulled through the conduits, perform a continuity test. Rosemount 935...

  • Page 32: Receiver/Transmitter Mounting

    M25x1.5 explosion-proof conduit connection/cable gland to assemble the cable/ explosion-proof conduit to the receiver. 3. Connect the wires to the required terminals (Figure 6-3, Item B) according to the wiring diagram. See Receiver terminal wiring, and Figure A-1, Figure A-2, Figure A-3, Figure A-4 Wiring configurations. Emerson.com/Rosemount...
  • Page 33 B. Transmitter or receiver holding plate C. Vertical crude alignment tightening screw D. Vertical fine alignment tightening screw E. Horizontal fine alignment tightening screw F. Horizontal crude alignment tightening screw G. Horizontal fine alignment screw H. Vertical fine alignment screw Rosemount 935...
  • Page 34 F. Vertical crude alignment tightening screw G. Vertical fine alignment screw H. Horizontal fine alignment screw I. Receiver tightening screw J. Receiver tightening washer K. Receiver L. Alignment tool M. Alignment tool tightening bolt N. Receiver back cover O. Receiver back cover secure bolt Emerson.com/Rosemount...

  • Page 35: Receiver Terminal Wiring

    The following table lists the functions of each electrical terminal of the receiver. Table 6-4: Wiring options Terminal number Function Power +24 VDC Return –24 VDC 0–20 mA In (+) 0–20 mA Out (–) RS-485 (+) RS-485 (–) Rosemount 935...

  • Page 36: Transmitter Wiring

    5. Place and secure the transmitter unit’s back cover by screwing on the cover and securing the back screw bolt. 6.9.2  Terminal wiring The contains 6 wiring terminals. Table 6-5: wiring options Terminal number Function Power +24 VDC Return –24 VDC Spare Spare Spare Spare Emerson.com/Rosemount...
  • Page 37 Reference Manual Installation instructions 00809-0100-4035 May 2023 Figure 6-4: Transmitter with cover removed A. Housing B. Terminal board C. Earth terminal D. Inlet conduit E. Internal earth connection F. Transmitter holding plate Rosemount 935...
  • Page 38 Installation instructions Reference Manual May 2023 00809-0100-4035 Emerson.com/Rosemount...

  • Page 39: Chapter 7 Operating Instructions

    PC. This section describes the alignment, calibration, and operation of the Rosemount 935 System.  CAUTION Accurate alignment is essential for proper operation of the Rosemount 935 system. 7.2  Alignment of unit The alignment tool is used to perform full alignment.

  • Page 40: Powering Up The System

    Follow the manual instructions, and refer to the drawings and specifications issued by the manufacturer. • Do not open the transmitter or receiver housing while power is connected. • External devices such as automatic extinguishing systems must be disconnected before performing maintenance tasks required by the warranty. Emerson.com/Rosemount...

  • Page 41: Signal Verification

    To perform the zero calibration procedure use the HART software (refer to the product web page), or Modbus software on the RS-485 interface (refer to the product web page). Procedure 1. Switch from normal to alignment mode indication. 2. Switch from alignment to standby mode. Rosemount 935...

  • Page 42: Functional Check

    0–20 mA output indicates 4 mA. 7.7  Functional check The Rosemount 935 system has been calibrated at the factory for the user's specific gas or vapor detection requirements. The functional check procedure validates the system’s functional operation.

  • Page 43: Chapter 8 Maintenance Instructions

    8.2.1  Routine optical surface cleaning The Rosemount 935 system, being an optical device, must be kept as clean as possible. The optical surfaces involved are the transmitter and receiver viewing windows. To clean the optical window: Procedure 1.
  • Page 44 8.2.3  Functional check of unit The Rosemount 935 has been calibrated at the factory according to the user’s specific gas or vapor detection requirements. Use the check filters included in the commissioning kit according to the corresponding calibrating gas to validate correct installation. Refer to Functional check for instructions.

  • Page 45: Chapter 9 Troubleshooting

    Perform alignment of the limit Dirt on the window Clean the window Receiver fault Replace/repair receiver Amber LED blinking at Transmitter fault Low/high input voltage Check the power supply the transmitter and installation Internal fault Replace the transmitter Rosemount 935...
  • Page 46 Troubleshooting Reference Manual May 2023 00809-0100-4035 Emerson.com/Rosemount...

  • Page 47: Declaration Of Conformity

    Reference Manual Declaration of Conformity 00809-0100-4035 May 2023 10  Declaration of Conformity Rosemount 935...
  • Page 48 Declaration of Conformity Reference Manual May 2023 00809-0100-4035 Emerson.com/Rosemount...

  • Page 49: Appendix A Wiring Configurations

    Reference Manual Wiring configurations 00809-0100-4035 May 2023 A  Wiring configurations Figure A-1: Receiver wiring terminal Figure A-2: Transmitter wiring terminal Rosemount 935...
  • Page 50 Wiring configurations Reference Manual May 2023 00809-0100-4035 Figure A-3: 0–20 mA sink 4-wire Figure A-4: 0–20 mA non-isolated sink 3-wire Figure A-5: 0–20 mA transmitter 3-wire Emerson.com/Rosemount...

  • Page 51: Appendix B Accessories

    Check filter part number Gas concentration 888260-1 110-270% LEL.m propane 888260-2 270-490% LEL.m propane 888260-3 140-250% LEL.m methane 888260-4 270-480% LEL.m methane 888260-5 180-370% LEL.m ethylene 888260-3 or 888260-6 490-760% LEL.m ethylene Note For LEL conversion see Table 3-1. Rosemount 935...

  • Page 52: Hart Handled Diagnostic Unit

    The USB RS-485 Harness Kit with RS-485/USB converter (P/N 794079), together with Modbus Manager host software, enables the user to connect to any available PC or laptop to reconfigure settings or perform diagnostics on the Rosemount 935 gas detection system.

  • Page 53: Appendix Csil-2 Features

    SIL-2 features This appendix details the special conditions for compliance with the requirements of EN 61508 for SIL-2. The Rosemount 935 Open-Path Gas can be used in low and high demand mode applications - see IEC 61508-4:2010, Chapter 3.5.16. C.1 ...
  • Page 54 SIL-2 features Reference Manual May 2023 00809-0100-4035 • Defects found in the detector must be repaired within 72 hours. Emerson.com/Rosemount...
  • Page 55 Reference Manual 00809-0100-4035 May 2023 Rosemount 935...
  • Page 56 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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