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Hach 911 User Manual

Hach 911 User Manual

Intrinsically safe flow meters
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Catalog Number 4979
911/940 Intrinsically Safe Flow Meters
USER MANUAL
January 2010, Edition 11
© HACH LANGE Company, 2007–2010. All rights reserved. Printed in the U.S.A.

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  • Page 1 Catalog Number 4979 911/940 Intrinsically Safe Flow Meters USER MANUAL January 2010, Edition 11 © HACH LANGE Company, 2007–2010. All rights reserved. Printed in the U.S.A.

  • Page 3: Table Of Contents

    4.1 Approved 911 and 940 Installation Drawings ................15 4.3 Installing the Batteries ....................... 30 4.3.1 Installing the Battery Pack in the 940 ................30 4.3.2 Installing the Battery Pack in the 911 ................31 4.3.3 Battery Compartment Desiccant ..................32 4.3.4 Estimating the Battery Life ....................32 4.3.5 Recharging the Lithium Ion Battery Pack for Model 940 ..........
  • Page 4 Table of Contents 7.1.1 Replacing the Battery Compartment Desiccant ..............57 7.2 Maintaining the O-Ring Gasket on the End Cap ...............57 7.3 Cleaning the Flow Meters ......................58 7.4 Storing the Flow Meters ......................58 7.5 Cleaning the Connectors ......................58 7.6 Maintaining the Electronics Compartment .................58 7.6.1 Fuses ..........................58 7.6.2 Memory Batteries ......................58 7.7 Replacing the Batteries in the RS232 Interface ................59...

  • Page 5: Section 1 Specifications

    Section 1 Specifications Specifications are subject to change without notice. Table 1 911 Flow Meter Specifications General Certification cCSAus Approved for Class 1 and Division 1, and Group C Dimensions 16.5 cm dia. x 57 cm L (6.5 in. x 22.5 in.) with 12 amp battery Weight 8 kg (17.5 lb) with 12 amp hour battery pack...
  • Page 6 Specifications Table 1 911 Flow Meter Specifications (continued) Depth Compensated 0 to 70 °C (32 to 158 °F) Temperature Material ® Noryl plastic outer shell with epoxy potting within 1.2 W @ 12 VDC Power Consumption Cable Material Urethane sensor cable with air vent Standard: 9, 15, 23, and 30.5 m (30, 50, 75, and 100 ft)
  • Page 7 Specifications Table 2 940 Flow Meter Specifications (continued) Submerged Area/Velocity Sensor Method: Doppler Ultrasound Twin 1 MHz piezoelectric crystals Typical Minimum Depth: 2 cm (0.8 in.) Velocity Measurement Zero Stability: 0.015 m/s (<0.05 ft/s) Accuracy: ± 2% of reading Recommended Range: –1.52 to 6.10 m/s (–5 to 20 ft/s) Method: Pressure transducer with stainless steel diaphragm Accuracy (static) ±0.16% full scale ±1.5% of reading at constant temp (±...
  • Page 8 Specifications Table 2 940 Flow Meter Specifications (continued) Operating Frequency 75 kHz Beam Angle 5° ±15.24 cm or 3.048 m ±0.003 m (±0.01 ft), at 22 °C (72 °F), still air, 40–70% relative humidity, Accuracy from 6 in. to 10 ft Range 10 ft Operating Temperature...

  • Page 9: Section 2 General Information

    Section 2 General Information 2.1 Safety Information Read the entire manual before unpacking, setting up, or operating this instrument. Pay particular attention to all danger and caution statements. Failure to do so could result in serious injury to the operator or damage to the equipment. To ensure that the protection provided by this equipment is not impaired, do not use or install this equipment in any manner other than what is specified in this manual.

  • Page 10: Hazardous Locations

    2.1.4 Intrinsically Safe Equipment The 911 and 940 Flow Meters are listed as “Intrisically Safe” for Class 1, Div.1, Groups C, and D Hazardous Locations. This means that the circuits within these flow meters are...
  • Page 11 General Information 2.1.4.2 Intrinsically Safe Wiring Practices DANGER Intrinsically safe wiring must be separated from non-intrinsically safe wiring to prevent the transferring of unsafe levels of energy to the hazardous area. DANGER Le câblage à sécurité intrinsèque doit être séparé du câblage à sécurité non intrinsèque afin d'empêcher tout transfert de niveaux d'énergie non sûrs vers la zone dangereuse.

  • Page 12: Confined Space Entry

    911 or 940 Flow Meters or Opto-Isolated Interfaces. 2.1.5 Confined Space Entry Important Note: The following information is provided to guide users of 911 and 940 Flow Meters on the dangers and risks associated with entry into confined spaces.
  • Page 13 General Information Important Note: Standard safety procedures must always be followed prior to entry into confined spaces and/or locations where hazardous gases, vapors, mist, dust, or fibers may be present. Note: Before entering any confined space, check with the employer for procedures related to confined space entry.
  • Page 14 General Information...

  • Page 15: Section 3 Getting Started

    Section 3 Getting Started 3.1 Installing the Flow Meter-Considerations 3.1.1 Choosing the Proper Site The accuracy of flow measurement depends on the suitability of individual monitoring sites. Select sites that have normalized flow and minimal turbulence. Turbulence can make it difficult to detect an average velocity in the flow stream. Obstructions, vertical drops, pipe bends, and elbows can create turbulence.
  • Page 16 Getting Started...

  • Page 17: Section 4 Meter Installation

    Figure 13 on page 28 are approved control drawings. These certified drawings detail the approved method of installing the 911 and 940 Flow ONLY Meters. Additionally, these drawings list both part number, description, and the only certified sensors, probes, and associated equipment to be used with these meters. Any substitutions automatically void the Intrinsically Safe certification of the flow meter and could result in fire or explosion.
  • Page 18 Meter Installation Figure 1 Control Drawing 911-V1...
  • Page 19 Meter Installation REVISION DESCRIPTION APPROVED REVISED PER R-3142-05 CONNECTION OF P/N 4080 FLASH CONVERTER TO 911 FLOW METER MUST BE MADE IN A NON HAZARDOUS LOCATION. NON HAZARDOUS (CLASSIFIED) LOCATION P/N 5150 10 FT/ 10 FT/ 3.1m FLOW METER 3.1m...
  • Page 20 Meter Installation Figure 3 Control Drawing 911-V3...
  • Page 21 Meter Installation Figure 4 Control Drawing 940-V1...
  • Page 22 Meter Installation Figure 5 Control Drawing 940-V2...
  • Page 23 ANYTHING, WHETHER OR NOT SHOWN HEREON/ THIRD ANGLE PROJECTION .XXX .005 REPRODUCED OR DISCLOSED TO ANYONE WITHOUT TITLE: ANGLES = DRAWING - CONTROL, DIRECT PERMISSION FROM HACH COMPANY. 940 FLASH CONV INTERPRET GEOMETRIC TOLERANCING PER: ANSI Y14.5 1994 SIZE DWG. NO. REV. 940-V3...
  • Page 24 Meter Installation Figure 7 Control Drawing 940-V4...
  • Page 25 Meter Installation Figure 8 Control Drawing 940-V5...
  • Page 26 Meter Installation Figure 9 Control Drawing 940-V8...
  • Page 27 Meter Installation Figure 10 Control Drawing 940-V9...
  • Page 28 Meter Installation Figure 11 Control Drawing 940-V10...
  • Page 29 Meter Installation Figure 12 Control Drawing 940-V14...
  • Page 30 Meter Installation Figure 13 Control Drawing 940-V15...
  • Page 31 Use the appropriate manhole support bracket/spanner bar. See Replacement Parts and Accessories on page Figure 14 Installation options Instrument Support Bracket (Cat. No. 5713000) 911 flow meter Manhole cover Wall/Ladder Mount Suspension Bracket (Cat. No. 4874 and Cat. No. 4839) Suspension harness (Cat. No. 4920)

  • Page 32: Installing The Batteries

    4.3 Installing the Batteries Never short circuit, puncture, deform, or incinerate any of the battery packs used in the 911 or 940 flow meters. Proper precautions must be observed in the handling, shipping, and disposal of battery packs. 4.3.1 Installing the Battery Pack in the 940 DANGER Never install, remove, or charge batteries in a hazardous location.

  • Page 33: Installing The Battery Pack In The 911

    The entire battery assembly unscrews and separates to access the battery connector (Cat. No. 5160-01). Follow the steps below to install the battery pack in the 911. 1. Hold the 911 Flow Meter by the handle on the end opposite of the interface connectors and twist counter-clockwise to open.

  • Page 34: Battery Compartment Desiccant

    Meter Installation 4.3.3 Battery Compartment Desiccant The battery compartment in both the 911 and 940 Flow Meters is kept dry with a small desiccant cartridge to avoid moisture damage to the batteries and power circuitry (Figure 17 Figure 18). When the beads are blue they can remove moisture from the enclosure. When they turn pink, they cannot absorb any more moisture.

  • Page 35: Recharging The Lithium Ion Battery Pack For Model 940

    Battery Life in Days 12 Amp-hour gel cell (Cat. No. 5160-01) Rechargeable lithium battery (Cat. No. 6608500) Typically 330 Batteries for the 911 and 940 flow meters should last as listed above under the following conditions: • 15 minute logging intervals •...

  • Page 36: Recharging The Battery Pack For Model 911

    To recharge the 911 Lithium Ion Battery Pack (5160-01): 1. Move the 911 Flow Meter to a non-hazardous location. 2. Remove the battery pack from the 911 Flow Meter as described in section 4.3.2 on page 3. Inspect the battery pack and the battery connection for any damage. Do not attempt to use or repair a damaged battery pack assembly.

  • Page 37: Wiring The Rs232 Interface

    35). The Opto-Isolated Interface (Cat. No. 4087) is used only for data downloading and remote programming. This interface isolates the energy potential in the PC from hazardous locations and from the 911 or 940 Flow Meters. Figure 19 RS232 Communications Setup Use “approved”...

  • Page 38: Wiring The Sampler Interface On Model 940

    Follow the steps mentioned below to route the RS232 Serial Port 1. Attach the cable with the round connector from the Opto-Isolated Interface to the connector on the 911/940 Flow Meter labelled RS232. 2. Attach the cable with a rectangular connector to the appropriate serial COM port on the PC or laptop.

  • Page 39: Sampler Receptacle (940 Only)

    Meter Installation BLUE ORANGE WHITE YELLOW BLACK GREEN YELLOW GREEN BLACK BROWN DO NOT TIN WIRES PRIOR TO TERMINATION Figure 20 Sampler Interface Wiring 4.6 Sampler Receptacle (940 Only) DANGER Do not attempt to connect any sampler to the 940 Flow Meter without the use of the Optically Isolated Sampler Interface (Cat.

  • Page 40: Connecting The Sampler Cable To A 940 Flow Meter

    Meter Installation • Sample history logging. Figure 21 Sampler Communications Use “approved” seal to minimize passage of gases or Sampler located in a non-hazardous location vapors from hazardous location to non-hazardous location. Optically Isolated Sampler Interface (Cat. No. 4274) in a 940 Flow Meter in a hazardous location non-hazardous location 4.6.1 Connecting the Sampler Cable to a 940 Flow Meter...
  • Page 41 Meter Installation Note: It is the installers responsibility to ensure compatibility and proper connection of a non-Sigma sampler to the Optically Isolated Sampler Interface. 1. Remove the cover from the Optically Isolated Sampler Interface. 2. Disconnect all the wires from the terminals labeled J4 through J6. Do not remove the wires from terminals labeled J1 through J3.
  • Page 42 Meter Installation...

  • Page 43: Section 5 Software And Communications

    Storage of 116,000 data points in battery backed RAM memory • Storm water sampling trigger option (940 only) • Flow proportional output option (940 only) For details on programming the 911 or 940 Flow Meter, refer to the software manual.
  • Page 44 Software and Communications...

  • Page 45: Section 6 Sensor Installation

    Section 6 Sensor Installation DANGER Only qualified personnel should conduct the tasks described in this section of the manual. DANGER Seul un technicien qualifié peut effectuer les tâches d'installation décrites dans cette section du manuel. DANGER All connections to the flow meter must be made in a non-hazardous location. DANGER Tous les raccordements au débitmètre doivent être effectués dans un environnement qui ne présente aucun danger.
  • Page 46 Sensor Installation sensor is “blind” to anything closer than the deadband and stops reading level when the distance is shorter than that. Figure 22 Invisible Range Maximum Range Highest expected water level Minimum Distance (must be at least 11 in. (29 cm) Invisible Range (set to ignore tops of channel walls) Beam Angle The beam angle from the bottom of the ultrasonic sensor spreads out at an angle of 5°...
  • Page 47 Sensor Installation Table 8 Beam Angle Spread by Distance Distance from Target (in.) 75 KHz Beam Width (in.) w/ Horn 11 (27.9 cm) 0.96 (2.4 cm) 12 (30.5 cm) 1.05 (2.67 cm) 13 (33.0 cm) 1.14 (2.9 cm) 14 (35.6 cm) 1.2 (3.1 cm) 15 (38.1 cm) 1.31 (3.3 cm)
  • Page 48 Sensor Installation This surface must be level. Figure 24 Permanent Bracket and Isolation Washers Wall/Rail Mount Bracket (Cat. No. 2974) Downlook Ultrasonic Sensor Isolation Washers (Cat. No. 6820) 1 inch x 0.25 Hex Nuts (Cat. No. 1429)
  • Page 49 Sensor Installation Figure 25 Adjustable Mounting Bracket (Cat. No. 2904) 14.75 inches (Cat. No. 3047) Sensor Mounting Clamp 15.25 inches (Cat. No. 3046) 14 cm (5.5 in.) tall (Cat. No. 3108) 16.625 inches (2) (Cat. No 3048) Horizontal and vertical sections are fully adjustable Sensor Mounting Clamp (with built-in bubble level) Sensor adjusts to any required level.

  • Page 50: Troubleshooting The Downlook Ultrasonic Sensor Installation

    Sensor Installation 6.1.2 Troubleshooting the Downlook Ultrasonic Sensor Installation Problem/Error Message Solutions Check the connection between the flow meter and the sensor. Check the sensor cable for cuts or nicks. Ultrasonic Failure Recalibrate the sensor. Look for unusual temperatures or the inability for a new calibrated (No signal from sensor) level to be read.

  • Page 51: In-Pipe Ultrasonic Sensor

    Sensor Installation 6.2 In-Pipe Ultrasonic Sensor The in-pipe ultrasonic sensor is used in pipes where level measurement near the top of the pipe is desired. The sensor reads the level until the liquid reaches the bottom of the sensor housing. The in-pipe sensor is not recommended for weir or flume applications due to limited range, but may be desirable in some applications.

  • Page 52: Angling The Beam

    Sensor Installation Figure 27 End View of In-Pipe Sensor Wastewater Bracket Thumbscrew Vibration Isolation Gasket Bubble Level Mounting Clip Sound Waves Pipe (size may vary) 6.2.2 Angling the Beam The narrow beam of sound that emanates from the bottom of the in-pipe ultrasonic sensor spreads out at an angle of ±12°...

  • Page 53: Protecting The In-Pipe Ultrasonic Sensor

    Sensor Installation 6.2.3.2 Calibrating the Liquid Depth Liquid depth calibration requires knowing the level or the depth of the liquid in the channel that is contributing to the flow. Liquid depth calibration is the recommended calibration method for the in-pipe sensor. Take a physical measurement of the liquid depth and enter the value into the application software.

  • Page 54: Troubleshooting The In-Pipe Sensor

    Sensor Installation 6.2.5 Troubleshooting the In-Pipe Sensor During surcharged conditions, the ultrasonic level gives random depth readings that need to be edited in the application software. Symptoms of this hydraulic condition occur when the level appears erratic within 5.7 cm (2.25 in.) of the pipe diameter.

  • Page 55: Connecting The Submerged Area/Velocity Sensor To The Mounting Bands

    Sensor Installation 6.3.2.1 Proper Strain Relief of Submerged Area/Velocity Sensor Cable Attach the desiccant hub to the instrument handle to provide a strain relief for the sensor cable and connector (Figure 28). Figure 28 Proper Strain Relief Flow Meter Carabineer Desiccant Hub Lanyard 6.3.3 Connecting the Submerged Area/Velocity Sensor to the Mounting Bands...

  • Page 56: Placing The Submerged Area/Velocity Sensor And The Mounting Band Into The Pipe

    Sensor Installation Figure 29 Attaching the Sensor to the Mounting Band Nylon Wire Ties Sensor Screws (2) Mounting band Figure 30 Avoiding Silt when Mounting the Sensor Pipe Sensor Silt Water 6.3.4 Placing the Submerged Area/Velocity Sensor and the Mounting Band into the Pipe Point the angle-face of the sensor into the flow.
  • Page 57 Sensor Installation Manhole Velocity Sensor Normal Upstream Position Manhole Velocity Sensor Downstream Position Figure 31 Placing the Sensor into the Flow...
  • Page 58 Sensor Installation...

  • Page 59: Section 7 Maintenance

    Use a light coating of O-ring lubricant to help maintain a water-tight seal. Table 10 on page lists replacement O-ring gaskets. Table 10 Replacement O-rings Description Part Number Model 911 End Cap O-ring (2 required) 4912 Model 940 End Cap O-ring (2 required) 4807...

  • Page 60: Cleaning The Flow Meters

    Maintenance 7.3 Cleaning the Flow Meters Clean the outside of the logger case with warm water and mild detergent. Do not use solvents or harsh cleaners to clean the logger. Do not use high pressure washing equipment to clean the case. 7.4 Storing the Flow Meters Remove all batteries from the logger when storing for long periods (more than 3 months).

  • Page 61: Replacing The Batteries In The Rs232 Interface

    Maintenance 7.7 Replacing the Batteries in the RS232 Interface DANGER Never replace batteries in a hazardous location. DANGER Ne jamais remplacer les piles dans une zone dangereuse. The Opto-Isolated RS232 interface uses a quantity of industrial quality Alkaline “C” cells. Under normal circumstances the batteries should last for more than 1,000 downloads based on an average download time of 5 minutes.

  • Page 62: Cleaning The Submerged Area/Velocity Sensor (Oil-Filled And Non-Oil)

    Maintenance 7.8.2 Cleaning the Submerged Area/Velocity Sensor (Oil-filled and Non-oil) Important Note: DO NOT interchange an oil-filled protective cover plate with a non-oil cover plate. This adversely affects level readings. It is possible to convert one type of sensor to the other using the Oil Probe Conversion Kit (Cat. No. 7730000), refer to the Oil Probe Conversion Kit Instruction Sheet, Cat.
  • Page 63 Maintenance Figure 33 Removing the Protective Cover (Non-Oil Sensor) Screws (#6–32 x Pressure Transducer Protective Cover Sensor Gasket Figure 34 Removing the Protective Cover (Oil-filled Sensor) Screws (#6–32 x Gasket Protective Cover Pressure Transducer Screw, set, #2-56 Sensor...

  • Page 64: Replenishing The Oil

    Maintenance 7.8.3 Replenishing the Oil The manufacturer recommends inspecting the oil in the sensor for large air bubbles during the customer-scheduled service duty cycle, and prior to every installation. Small bubbles (less than ¼-in. diameter) of air within the oil do not affect performance. Larger bubbles may minimize the anti-fouling benefit of the oil.

  • Page 65: Changing The Submerged Area/Velocity Sensor Desiccant

    Maintenance Figure 36 Attaching the Feed Tube and Syringe Figure 37 Oil Replenishment Sensor Side port Set screw Syringe 7.8.4 Changing the Submerged Area/Velocity Sensor Desiccant The desiccant canister contains beads of silica gel which ensure proper orientation of the pressure transducer.

  • Page 66: Replacing The Desiccant

    Maintenance 7.8.5 Replacing the Desiccant Note: Replacing the desiccant does not require that the desiccant container be removed from the desiccant box. 1. Twist the bottom end-cap using a slight twisting motion until its slots align with the retaining clips (Figure 38).
  • Page 67 Maintenance 7.8.5.1 Replacing the Hydrophobic Filter ® A single Teflon hydrophobic filter (Cat. No. 3390) is installed in the top of the canister to prevent liquid from entering the vent tube. For best performance and to avoid grease buildup on the filter during submergence or surcharge conditions, hang the canister vertically so that the end facing the sensor points downward.
  • Page 68 Maintenance...

  • Page 69: Section 8 Replacement Parts And Accessories

    Section 8 Replacement Parts and Accessories 8.1 Flow Meter Replacement Parts Description Part Number Battery, 12 AH (Model 911 only), rechargeable 5160-01 Charger, lead acid battery (Model 911 only) RS232 Intrinsic Safety Barrier 4087 AC Power, 115 V with 2 AH battery backup and intrinsically safe barrier...

  • Page 70: Ultrasonic Sensor Mounting Hardware

    Replacement Parts and Accessories 8.3 Sensor Mounting Rings and Bands (continued) Description Part Number 10 inches 1363 12 inches 1364 15 inches 1365 18 inches 1366 21 inches 1353 24 inches 1370 Submerged Pressure/Velocity Mounting Bands for 15 to 42 in. Pipes 15 inches 9706100 18 inches...

  • Page 71: Mounting Plate Hardware For Directly Mounting To Pipe Wall

    Replacement Parts and Accessories 8.5 Mounting Plate Hardware for Directly Mounting to Pipe Wall Part Number Sensor Type Submerged Pressure 4939 In-Pipe 3875...
  • Page 72 Replacement Parts and Accessories...

  • Page 73: Section 9 Contact Information

    • Quantity Ordering Information for Outside the U.S.A. and Europe Hach maintains a worldwide network of dealers and distributors. To locate the representative nearest you, send an e-mail to: hachflowsales@hach.com or visit ww.hachflow.com. Technical Support Technical and Customer Service Department personnel are eager to answer questions about our products and their use.

  • Page 74: Section 10 Contact Information For Europe

    Ph: +-32-87-899797 or 899799 Fx: +-32-87-899790 Email: info@flow-tronic.com www.flow-tronic.com For France, Spain and Great Britain: France HACH LANGE FRANCE S.A.S.33 Rue du Ballon 93165 Noisy-le-Grand Telephone: ++33 (0)1 48 15 68 70 Fax.: ++33 (0)1 48 15 80 00 Email: info@hach-lange.fr www.hach-lange.fr Spain HACH LANGE, S.L.U...

  • Page 75: Section 11 Limited Warranty

    In the event that a defect is discovered during the warranty period, Hach Company agrees that, at its option, it will repair or replace the defective product or refund the purchase price excluding original shipping and handling charges.

  • Page 77: Appendix A Working With Primary Devices

    Appendix A Working with Primary Devices A.1 Working with Primary Devices and Sensor Operation Installing the sensor in any primary device requires familiarity with the proper location for head measurement in that particular primary device. Just as the proper installation of the primary device itself is critical to obtaining optimum flow measurement accuracy, the appropriate location of the submerged or ultrasonic sensor also greatly affects flow measurement accuracy.
  • Page 78 Working with Primary Devices Submerged Draw down Head Probe Maximum Measurement Head Height Point Crest FLOW FLOW Minimum Crest Height Weir Plate Submerged Minimum Distance from Probe Weir Plate Figure 40 Weir...
  • Page 79 Working with Primary Devices Stilling Well (Optional) Length of Converging Section 2/3A Length to Stilling Well Submerged Probe TOP VIEW FLOW Head Measurement Point Submerged Probe ELEVATION Submerged Flow Free Flow Figure 41 Parshall Flume...
  • Page 80 Working with Primary Devices Submerged Probe (Preferred Head Measurement Point) FLOW Top View Lower Throat Upper Transition Transition Preferred Head Measurement Point Water Surface Small jump should occur here. FLOW Elevation View Downstream Depth "D" Conduit Diameter Upstream Depth Figure 42 Palmer-Bowlus Flume (with Integral Approach)
  • Page 81 Working with Primary Devices Submerged Probe (Preferred Head Measurement Point) FLOW Top View Upper Transition Throat Lower Transition Preferred Head Measurement Point Small jump should occur here. Water Surface FLOW Elevation View End View "D" Conduit Diameter Downstream Depth Upstream Depth Figure 43 Leopold-Lagco Flume...
  • Page 82 Working with Primary Devices FLOW Top View Inlet Bulkhead Head Measurement Section FLOW Elevation View Approach Section Pipe Stub Figure 44 H-Flume Top View FLOW (Q) Elevation View ΔY ΔX Figure 45 Round Pipes...

  • Page 83: Appendix B Channel Installation Options

    Appendix B Channel Installation Options Figures through show how to install the 911 and 940 Flow Meters in various applications. Figure 46 shows Model 911 installed in a manhole with a single level/velocity sensor stored in the small-diameter pipe. Figure 46 Small-Diameter Pipes Down to Street or Building Collectors...
  • Page 84 Channel Installation Options The 940 and the 911 Flow Meters do not require profiling to establish average velocity, allowing setup in a dry channel (Figure 47). Rapid signal processing and temperature compensation accurately record the change from dry to wet conditions.
  • Page 85 Channel Installation Options Figure 48 shows a storm vault accepting flow from two locations. The 940 Flow Meter monitors level, velocity, and flow in both pipes and sends data via modem to a central location. Figure 48 Installation for Multiple Source Monitoring at a Single Site...
  • Page 86 Channel Installation Options When a Combined Sewer Overflow (CSO) is conducive to accurate flow measurement, the 940 Flow Meter can measure depth and velocity in the primary channel and measure discharge in the overflow channel. See Figure 49. In some instances, the overflow in some CSO applications may be too turbulent for accurate measurement.
  • Page 87 Channel Installation Options Custody transfer or interagency billing demand redundant measurement for chain of custody. In Figure 50, the 940 Flow Meter provides ultrasonic measurement of flow in a Parshall flume while also measuring flow upstream using the Continuity Equation (Q=AV). This ensures no loss of data in a submerged flow condition.
  • Page 88 Channel Installation Options...

  • Page 89: Appendix C Batteries And Chargers

    5 to 35 °C (47 to 95 °F) temperature range is recommended. Disposal • 911 Flow Meter: The battery pack assembly for the 911 Flow Meters are rechargeable/disposable. Follow local applicable disposal guidelines for gel–electrolyte type batteries. The entire battery housing is meant to be disposed of after the service life of the battery.
  • Page 90 Batteries and Chargers Gel Cell Self Discharge Characteristics 100% 0 °C 10 °C 20 °C 30 °C 40 °C Storage Time (months) Figure 51 Battery Discharge Characteristics Table 12 Lead-Acid Battery Storage Recommendations Storage Temperature Maximum Recommended Storage Time 0 to 20 °C 12 months 21 to 30 °C 9 months...
  • Page 91 The batteries must be individually wrapped and boxed separately. Do not puncture, incinerate or expose to water. If local government does not allow for the disposal of these batteries contact the Hach Company for proper disposal arrangements.
  • Page 92 Batteries and Chargers...

  • Page 93: Appendix D Scada-Modbus® System Guidelines

    ® Appendix D SCADA-Modbus System Guidelines D.1 Introduction to SCADA - Modbus Communications Use this section as a guide when using the Modbus ASCII protocol to communicate directly with the 940 Flow Meter via an RS232 or modem connection. This guide assumes that the user has a working knowledge of Supervisory Control and Data Acquisition (SCADA), its components, and the different topologies used to construct the communications network.
  • Page 94 SCADA-Modbus® System Guidelines D.4 Function Field The function code field of an ASCII message frame, ranging from 1 to 255 decimals, consists of two characters that represent the type of action the master is requesting from the slave. Of these functions, the 940 Flow Meter currently supports function 3 (Read Holding Registers).
  • Page 95 SCADA-Modbus® System Guidelines Table 13 Modbus ASCII Memory Input/Output Referencing System Reference Indicator Reference Type Meaning 0xxxx Discrete Output or Coil Binary 1xxxx Discrete Input Binary 3xxxx Input Register Real 4xxxx Output Holding Register Real 6xxxx Extended Memory Register Real The memory data is stored in 16-bit words.
  • Page 96 SCADA-Modbus® System Guidelines Table 15 Channels’ Units of Measure Read Holding Register Addresses Start Address Start Address Name Type Size (bits) # of Registers Registers Temperature Integer 40050 Rainfall Integer 40051 pH (or ORP) Integer 40052 Level 1 Integer 40053 Velocity 1 Integer 40054...
  • Page 97 SCADA-Modbus® System Guidelines Table 17 SCADA-Modbus Units of Measure Codes Unit Code Unit Code DEGREE_F MILS VOLTS PCT_O2 PCT_H2S PCT_LEL D.10 Query The Modbus ASCII query must take the form shown below that specifies the starting register and number of registers to be read: Start Start Start...
  • Page 98 SCADA-Modbus® System Guidelines D.11 Response The 940 Flow Meter responds with the following transmission reflecting a level reading of 15.0 inches: Table 19 Transmission Response that Reflects a 15 in. Level Reading Start ‘:’ Slave Address Function Byte Count Data High Data Low Data High Data Low...
  • Page 99 SCADA-Modbus® System Guidelines D.13 Complications with Floating Point Values The manufacturer’s implementation of the Modbus protocol was based on the idea that we ® would enable our flow meters to emulate a Modicon , Compact 984 PLC. Consequently, we follow the exact same format that Modicon uses for the storing and processing floating point numbers.
  • Page 100 SCADA-Modbus® System Guidelines D.14 Port Expanders and Protocol Converters In some situations, there may not be a Modbus ASCII port available for use with the 940 Flow Meter. A good example might be where there is a need to install a flow meter at a remote pump site that already has a single Modbus line connected to a PLC that is used to control the pumps.
  • Page 101 SCADA-Modbus® System Guidelines Problem: 940 Flow Meter does not respond to any Modbus message requests Note: It is imperative that the DTR be asserted prior to the communication session and that it remains asserted throughout the entire communication session. Response: Check the DTR Signal/Line The 940 Flow Meter will not respond to any Modbus messages until the device connected to the RS232 port asserts (raises) the DTR line (DB-9, Pin 4 on the 1727 cable).
  • Page 102 SCADA-Modbus® System Guidelines Likewise, if polling the meter for engineering units, which are represented by integer values, such as Flow Units of Measure or Level Units of Measure, the Modbus server or MMI must be configured to read these values as Integers. If the server or MMI is formatting this data as any data type other than Integer, the values will not be read or displayed correctly.
  • Page 103 Special Output/Sample Output ......... 38 Installing the Battery Pack ........30 Specifications ............. 3 Intrinsically Safe Equipment ........8 911 ............... 3 Intrinsically Safe Installation Requirements ....8 940 ............... 4 Intrinsically Safe Wiring Practices ......9 Storing the Flow Meters ........... 58 Invisible Range ............

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