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Solartron Mobrey 7828 Technical Manual

Density transmitter
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Precision measurement solutions
7828
TECHNICAL MANUAL
78285000
Density Transmitter

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Summary of Contents for Solartron Mobrey 7828

  • Page 1 Precision measurement solutions 7828 TECHNICAL MANUAL 78285000 Density Transmitter...
  • Page 2 Copyright © 2001 Solartron Mobrey Ltd. All Rights Reserved Solartron-Mobrey pursues a policy of continuous development and product improvement. The specification in this document may therefore be changed without notice. To the best of our knowledge, the information contained in this document is accurate and Solartron- Mobrey cannot be held responsible for any errors, omissions or other misinformation contained herein.
  • Page 3 Test pressure. ENSURE all explosion proof requirements are applied ENSURE transmitter and associated pipework are pressure tested to 1½ times the maximum operating pressure after installation. ALWAYS store and transport the 7828 in its original packaging. 78285000_AB...
  • Page 4 7828 Density Transmitter Technical Manual 78285000_AB...

  • Page 5: Table Of Contents

    7828 Density Transmitter Technical Manual Contents Contents SECTION 1 - INTRODUCTION ABOUT THE 7828 DENSITY TRANSMITTER........1-1 1.1.1 What is it? ..................1-1 1.1.2 7828 measurements ................1-2 1.1.3 What is it used for? ................1-2 1.1.4 Typical 7828 application ..............1-3 7828 OPTIONS...................
  • Page 6 7828 Density Transmitter Technical Manual SECTION 3 - ELECTRICAL INSTALLATION INTRODUCTION.................3-1 INSTALLATION CONSIDERATIONS ..........3-2 3.2.1 Power supply ..................3-2 3.2.2 EMC ....................3-2 3.2.3 Ground connections................3-2 3.2.4 Cabling....................3-2 3.2.5 Surge protection.................3-3 WIRING THE 7828................3-4 3.3.1 Wiring Procedure ................3-5 CONNECTIONS..................3-7 3.4.1 Power....................3-7 3.4.2 RS485 ....................3-7...
  • Page 7 7828 Density Transmitter Technical Manual Contents SECTION 5 - CALIBRATION CHECK CALIBRATION ................... 5-1 5.1.1 Factory calibration ................5-1 5.1.2 Calibration of transfer standards ............5-1 5.1.3 Instrument calibration ................ 5-1 5.1.4 General density equation..............5-2 SAMPLE CALIBRATION CERTIFICATE..........5-3 USER CALIBRATION CHECKS............
  • Page 8 7828 Density Transmitter Technical Manual APPENDIX B - CALCULATED PARAMETERS INTRODUCTION................B-1 BASE DENSITY REFERRAL............. B-2 B.2.1 Matrix density referral ............... B-2 B.2.2 API density referral ................B-3 CALCULATED PARAMETERS............B-6 B.3.1 Specific Gravity ................. B-6 B.3.2 Degrees Baumé................B-6 B.3.3...
  • Page 9 7828 Density Transmitter Technical Manual Contents D.5.13 User selected alarm variable ............D-11 D.5.14 Unit type..................D-11 D.5.15 Status Register flags............... D-12 ESTABLISHING MODBUS COMMUNICATIONS ......D-13 EXAMPLE OF DIRECT MODBUS ACCESS ........D-15 D.7.1 Example 1: Reading line density (16-bit register size)....D-15 D.7.2...
  • Page 10 7828 Density Transmitter Technical Manual 78285000_AB...

  • Page 11: About The 7828 Density Transmitter

    The 7828 is factory set to perform either API or Matrix referrals. Re-configuration of the 7828’s default settings (see Appendix A) is achieved by linking a PC to the Modbus (RS485) connection and running Solartron's ADView software.

  • Page 12: 7828 Measurements

    1.1.3 WHAT IS IT USED FOR? The 7828 Transmitter is ideally suited to applications where continuous real time measurement of density is required, for example in process control where density is the primary control parameter for the end product, or is an indicator of some other quality control parameter such as % solids or % concentration.

  • Page 13: Typical 7828 Application

    Windows Tool This shows and outline of a typical wet process mineral application where 7828 provides a 4-20mA signal of the %solids determination from the slurry stream. From this signal and the measured volumetric flowrate, net mass flowrate is determined.

  • Page 14: 7828 Options

    7828 Density Transmitter Technical Manual 7828 OPTIONS A number of options are available for the 7828. They are identified by suffixes appended to the transmitter type number. The table below summarises these. Some of the suffixes are allocated to future developments and the letter code is currently fixed.

  • Page 15: Introduction

    Mechanical Installation INTRODUCTION There are a variety of external factors which affect the ability of the 7828 to operate successfully. In order to ensure that your system works correctly, the effects of these factors must be taken into consideration when designing your installation.
  • Page 16 This chapter has the following sections: Section 2.2 - The importance of boundary and viscosity effects Section 2.3 - Mechanical details for mounting and installing 7828 Section 2.4 - Optimising measurement accuracy and repeatability Section 2.5 - Commissioning the system...

  • Page 17: Boundary And Viscosity Effects

    The diagram below illustrates the 7828 installed in a pocket on the side of a 4” (100mm) horizontal pipe line (viewed from above). The effective region is completely enclosed within the pipe line and thus is completely fluid.
  • Page 18 Mechanical Installation 7828 Density Transmitter Technical Manual 2”Schedule 40 4” horizontal pipe Pocket or “T” Top or Plan view This next view shows other pipe outlines superimposed: 4” (100mm) 6”(150mm) vertical pipe vertical pipe 2”Schedule 40 Pocket or “T” Top or Plan view The smaller circle represents a 4”...
  • Page 19 7828 Density Transmitter Technical Manual Mechanical Installation 2”Schedule 40 Pocket or “T” Top or Plan view From this, it would appear that almost every installation requires a separate in situ calibration - a very undesirable situation. The problem is resolved by providing standard calibration geometries which can be used in all pipe work configurations and thereby allow the factory calibration conditions to be reproduced in the process.

  • Page 20: Viscosity Effects

    7828 Density Transmitter Technical Manual 2.2.2 VISCOSITY EFFECTS The 7828 can be affected by the viscosity of the fluid surrounding it. This is manifested in two ways: 1. An error in the density measurement, due to the effect of viscosity on the vibration of the fork tines;...

  • Page 21: Standard Installations

    To overcome the need for in-situ calibration for every installation, three 'standard' installations are proposed. If an installation conforms to one of these standards, the factory calibration of the 7828 is valid, and in-situ calibration unnecessary. The three installations are summarised below.

  • Page 22: 7828 Orientation

    2.3.1 7828 ORIENTATION For Free-stream and T-piece installations, it is essential that the 7828 is always orientated with the transducer horizontal and the slot between the tines vertical. This is irrespective of the pipe line orientation, and helps to prevent the trapping of bubbles or solids on the transducer.

  • Page 23: Free Stream Installation - Flanged Fitting

    7828 Density Transmitter Technical Manual Mechanical Installation 2.3.2 FREE STREAM INSTALLATION - FLANGED FITTING Conditions: Flow: 0.3 to 0.5m/s (at the transducer) Viscosity limit: Up to 20 000cP Temperature: -50°C to 200°C Note that the thermal mass of the flanges may affect the response time of the transducer to temperature changes.

  • Page 24: Free Stream Installation - Weldolet

    The weldolet has a 1.5" taper lock fitting, and is supplied to be welded on 4", 6", 8" or 10" pipelines. Use of the weldolet ensures that the tines of the 7828 are orientated correctly and are fully inserted into the fluid stream.

  • Page 25: T-Piece Installation

    7828 Density Transmitter Technical Manual Mechanical Installation 2.3.4 T-PIECE INSTALLATION Conditions: Flow: 0.5 to 3.0m/s (at the main pipe wall) Viscosity: Up to 100cP, or 250cP under some conditions (See section 2.2.2) Temperature: -50°C to 200°C The thermal mass of the flanges may affect the response time of the transducer to temperature changes.

  • Page 26: T-Piece Weldolet Installation

    The weldolet has a 1.5" taper lock fitting, and is supplied to be welded on 4", 6", 8" or 10" pipelines. Use of the weldolet ensures that the tines of the 7828 are orientated correctly and are fully inserted into the fluid stream. The length of the weldolet is determined by the flow rate in the main pipeline (refer to the table in the diagram below), and is chosen to ensure that the tines of the 7828 are sufficiently retracted from the main pipe wall.

  • Page 27: Flow-Through Chamber Installation

    7828 Density Transmitter Technical Manual Mechanical Installation 2.3.6 FLOW-THROUGH CHAMBER INSTALLATION This chamber is fabricated by Solartron, and is available with either weld prepared ends or with flange or compression fittings for connection into the process pipe lines. It is available with 1”...

  • Page 28: Installation In The Pipeline Or System

    2.4.1 FLUID AT THE SENSOR The fluid in the effective zone of the 7828 must be of uniform composition and at uniform temperature. It must be representative of the fluid flow as a whole. This is achieved either by mixing of the fluid either using a static inline mixer or taking advantage of any natural pipe condition that tends to cause mixing, such as pump discharge, partially open valves etc.

  • Page 29: Flow Rate

    (e.g. bends). •= Maintain flow velocity at the sensor within the specified limits. •= Use filtration if necessary. •= Specify the 7828 transmitter with a non-stick PTFE protective layer. 2.4.6 EXAMPLE INSTALLATION The diagram below illustrates some of the principles outlined in this section. It shows a free-stream density transmitter installation with an additional sample take off.

  • Page 30: Commissioning

    Lower density by-pass installed sensors COMMISSIONING 1. Once the pipework installation has been prepared, and before installing the 7828, fit a blanking flange or compression nut to the 7828 mounting, and pressurise and flush the system. 2. Isolate the system, depressurise and remove the blanking flange or compression nut.

  • Page 31: Section 3 - Electrical Installation

    • • • • = = = = Analog connections (Section 3.4.5) Note: If 7828 is to be used in hazardous areas, the electrical installation must strictly adhere to the relevant safety drawings, given in Appendix C of the paper manual.

  • Page 32: Installation Considerations

    Current: >50mA. If several 7828 transmitters are to be used within a local area, one power supply can be used to power them all; where the transmitters are distributed over a wide area and cabling costs are high, it may be more cost effective to use several smaller, local power supplies.

  • Page 33: Surge Protection

    If there is a possibility of lightning strikes, external surge protection devices - one for each pair of signals and the power supply - should be installed as close to the 7828 as possible. Another method is to connect an MOV (Metal Oxide Varistor) (breakdown voltage >30V) with an NE-2 neon bulb in parallel across each wire and ground.

  • Page 34: Wiring The 7828

    The main 24V power supply must supply between 20 and 28V dc at 70mA. The RS485/232 converter and PC are not normally installed permanently. However it is strongly recommended that the wiring to the 7828 is made at installation. The 4-20mA analog output is not self-powered: an external supply is required. The main power supply can be used for this purpose if appropriate.

  • Page 35: Wiring Procedure

    Fit the M20 gland adaptor into the lowest hole, then fit the M20 x 1 cable gland to the adapter. Fit the ½” NPT blanking plug to the unused hole in the 7828. ½” NPT to M20 adapter M20 cable gland...
  • Page 36 Electrical Installation 7828 Density Transmitter Technical Manual Insert the cable through the cable gland and adaptor so that the multi-core cable is gripped leaving 200mm of free, unscreened wire to connect to the terminal blocks. Wire up the cable cores as...

  • Page 37: Connections

    Connect a suitable 24V power supply to pins 1 and 2 of the transmitter. Ensure that the loop resistance of the cables is such that the voltage at the transmitter terminals is greater than 20 volts. (The maximum voltage at the 7828 terminals is 28V.) 3.4.2 RS485 The Modbus standard uses the RS485 electrical standard.

  • Page 38: Rs485 To Rs232

    PC’s RS232 port, to programmable devices with full isolation between the two networks. Note: 7828 uses a half-duplex implementation of RS485, such that the A and B signals are used for data transmission in both directions. This requires that the RTS line is toggled to indicate the transmission direction.
  • Page 39 7828 Density Transmitter Technical Manual Electrical Installation 25 pin 9 pin 9 pin connector connector connector (socket) (plug) (socket) 7828 4 (B) 3 (A) 2 (A) To PC 3 (A) K485-ADE 6 (B) 7 (B) RS232/RS485 Converter 5 (GND) 9 (+9V)
  • Page 40 7828 Port 1 GND Power Input Note: The ‘A’ signals on the 7828 must be connected to the ‘B’ signal on the converter, and vice-versa. In most systems, the ground connection will be unnecessary. When two or more devices are connected on the same RS485 network, this is known as a multidrop configuration (see next section).

  • Page 41: Rs485 Multidrop

    15 to 28V dc at the 4-20mA terminals of the 7828. A power supply is also required for the 7828 itself, but this can also power the 4-20mA loop, if appropriate.

  • Page 42: Installation In Explosive Areas

    7828 power). 7828 INSTALLATION IN EXPLOSIVE AREAS The 7828 density transmitter is an explosion/flame-proof device, and therefore the connections shown in the wiring schedule are applicable. However, it is essential to observe the rules of compliance with Current Standards concerning flameproof equipment: 1.

  • Page 43: Section 4 - Using Adview

    PC’s serial (RS232) ports. ADView requires Microsoft’s Windows operating system: Windows 3.1, 95, 98 or NT. Note: To connect to an RS485/Modbus device, such as the 7828, you will need an adapter between the PC and the transmitter (see Section 3).

  • Page 44: Starting Adview

    Modbus device to one of the PC’s serial ports, or you can use ADView’s built in simulation of a tube or fork density transmitter, such as the 7835 or 7828, to gain some experience with the software.
  • Page 45 Optional 9V power supply ADView automatically configures the selected port with the correct settings for the device. For 7828 this is 9k6 baud, 8 data bits, no parity, 1 stop bit, Xon/Xoff (software) flow control. Note for Windows NT users An interesting feature of Windows NT is that it does not allow the RTS line to be toggled directly;...
  • Page 46 Introduction 7828 Density Transmitter Technical Manual If no active device is found, a warning message is given: In this case, check that the device is powered up correctly, that the cables and adapter are pushed fully home, and that the communications settings on the device and selected serial port are the same.

  • Page 47: Using Adview

    7828 Density Transmitter Technical Manual Introduction USING ADVIEW 4.4.1 ADVIEW FACILITIES The main ADView window gives access to the various facilities available. A brief description of each is listed below. Using the facilities is largely intuitive, and hands-on experience is probably the best way to learn about the system.

  • Page 48: Menu Bar

    4.4.7. Check the value in Register 30 (Modbus Slave Address). If it is not the required value, enter the desired value and click on the write button. The 7828 will now be configured with the new slave address.

  • Page 49: Board Configuration

    The 7828 configuration controls the way in which the transmitter will process and present data, user settings, calibration constants and other factors. This data is stored in non- volatile memory known as registers; a full list of the registers used in 7828 is given in Appendix D.
  • Page 50 Introduction 7828 Density Transmitter Technical Manual Shows which unit is being configured. Enter values of variable to give 4mA and 20mA analog outputs Select variable to control 4-20mA output. The calculated parameters Select units for (special variable controlling functions) analog output...
  • Page 51 7828 Density Transmitter Technical Manual Introduction Referral Calculation To configure the referral calculation, you will need to enter the relevant information. For matrix referral, this is a set of four values of density for each of up to five different temperatures;...

  • Page 52: Data Logging

    Introduction 7828 Density Transmitter Technical Manual 4.4.5 DATA LOGGING ADView’s Data Logging function is a useful tool for checking setups and performing experimental data capture. The diagram below explains some of the features. Shows which parameter Graphical has been configured to the...

  • Page 53: Register Dump/Load

    4.4.6 REGISTER DUMP/LOAD This facility is essential for saving the configuration of your 7828. You should use it to save the current configuration before you start to alter it, in order to restore it if things go wrong for any reason. Also, if you send the transmitter away for servicing or re- calibration, you should save the current configuration.

  • Page 54: Register Read/Write

    In a few cases, it may be useful to write directly to a single Modbus register. (See Appendix D for a complete list of 7828’s registers.) Two likely occasions are to set the Slave Address of the unit, and to configure a density offset.

  • Page 55: Section 5 - Calibration Check

    5.1.3 INSTRUMENT CALIBRATION Each 7828 Transmitter is issued with its own calibration which is programmed in to the instrument electronics before it leaves the factory. The calibration data is shown on a calibration certificate supplied with the instrument, an example of which is shown overleaf.

  • Page 56: General Density Equation

    7828’s registers, and should not be altered. If the 7828 is used in an application dissimilar to the one for which it was originally calibrated, it may be necessary to re-calculate the K coefficients. Contact Solartron for further details.

  • Page 57: Sample Calibration Certificate

    7828 Density Transmitter Technical Manual Calibration check SAMPLE CALIBRATION CERTIFICATE Note: This is an example only - it is NOT the calibration certificate for your 7828. 78285000_AA...

  • Page 58: User Calibration Checks

    3. Apply power to the instrument and check that the time period of the instrument agrees with the figure shown on the calibration certificate to within ±100ns. If the 7828 is not at 20°C, compensate for this by adding an offset of +110ns for every °C above 20°C, or by subtracting an offset of +110ns/°C below 20°C.
  • Page 59 Refer this to the operating conditions at the transducer. 5. Calculate the density offset required to make the 7828 measurement the same as the measured density of the sample. 6. Using ADView’s Register Read/Write tool (see section 4.4.7), configure the 7828 with the calculated line density offset (Register 173).
  • Page 60 Calibration check 7828 Density Transmitter Technical Manual 78285000_AA...

  • Page 61: Section 6 - Maintenance

    GENERAL The 7828 Density Transmitter has no moving parts and maintenance is limited to simple visual checks for leaks and physical damage. ADView’s Data Logging facility can be used whenever necessary to verify that the transmitter is functioning correctly.

  • Page 62: General Maintenance

    Maintenance 7828 Density Transmitter Technical Manual GENERAL MAINTENANCE This procedure is recommended for periodic maintenance and can also be used when fault finding. 6.2.1 PHYSICAL CHECKS a. Examine the transmitter, its electronics housing and cables for any signs of damage and corrosion.

  • Page 63: Fault Analysis And Remedial Action

    7828 Density Transmitter Technical Manual Maintenance FAULT ANALYSIS AND REMEDIAL ACTION A fault may be categorised as either an erratic reading or a reading which is outside limits. Electrical faults can also cause symptoms which appear to affect the readings and it is recommended that the electrical system is checked first, before removing the transmitter for servicing.

  • Page 64: Mechanical Servicing

    Disturbances in the fluid caused by bubbles, cavitation or contaminants can cause sudden changes in the measured output, which may, under some circumstances, give rise to instability (i.e. hunting) in a control system relying on the measurement. The 7828 can maintain the analog output during such perturbations by ignoring the aberrant measurement, and maintaining the output at the last good measured value.
  • Page 65 If you want to program another value, it should be determined experimentally, and be equal to the length of the longest undesirable transients which are likely to arise. If the value is set too high, the 7828 will be slow to respond to genuine changes in the fluid properties.
  • Page 66 Maintenance 7828 Density Transmitter Technical Manual 78285000_AA...

  • Page 67: Appendix A - Specification

    Specification GENERAL The 7828 Insertion Density Transmitter comprises a vibrating fork density sensor, with processing electronics within the housing which provide full on node configuration; all signal processing, calculations, and calibration adjustments are made without the need for external electronics.

  • Page 68: Environmental

    Specification 7828 Density Transmitter Technical Manual Temperature Temperature Technology PT100 platinum resistance thermometer in tuning fork Integral PRT Temperature -50° to +200°C Range Integral PRT Temperature BS1904 Class B , DIN 43760 Class B Accuracy A.2.2 ENVIRONMENTAL Operating temperature range -50°...

  • Page 69: Rs485 Interface

    7828 Density Transmitter Technical Manual Specification A.2.5 RS485 INTERFACE Connections A and B signals (screw terminals) Communications protocal Modbus RTU Isolation None - RS485 in same circuit as main power supply Baud rate 9600 (fixed) Termination not required A.2.6 APPROVALS...

  • Page 70: Factory Default Configuration

    The 7828 can be supplied in one of three standard configurations (see Section 1.2, 7828 Options). For Factory Configuration Option A, the 7828 is set to provide line density as the 4-20mA output, and the units are kg/m for density and °C for temperature.
  • Page 71 7828 Density Transmitter Technical Manual Specification Product type General crude General crude API referral User K0 +0000E+00 +0000E+00 User K1 +0000E+00 +0000E+00 Base temperature Base pressure 1.1013 14.5 Special Type None None Functions Name 0 (None) 0 (None) Units None...
  • Page 72 Specification 7828 Density Transmitter Technical Manual 78285000_AB...

  • Page 73: Appendix B - Calculated Parameters

    Calculated Parameters INTRODUCTION The 7828 Density Transmitter is capable of calculating a number of parameters based on the measured line density and temperature. These calculated parameters are often referred to as ‘special functions’. Only one calculated parameter is available at any one time;...

  • Page 74: Base Density Referral

    T to T . Using this information, and the measured line density and temperature, the 7828 calculates the base density at the base temperature. The information required for the referral is: • Five reference temperatures •...

  • Page 75: Api Density Referral

    The information required for the API density is:- • Reference pressure and reference temperature • Line pressure - this is not measured by 7828, and must be entered as part of the configuration. • Product type: Refined product, crude product or user defined.
  • Page 76 Calculated parameters 7828 Density Transmitter Technical Manual For refined products the values of K and K are automatically selected according to the corrected density: Hydrocarbon Density Range Group (kg/m³) Gasolines 654 to 779 346.42278 0.43884 Jet Fuels 779 to 839 594.54180...
  • Page 77 7828 Density Transmitter Technical Manual Calculated parameters A correlation equation has been established for β from the available compressibility data; i.e., ( ρ ( ρ C = -1.62080 + 0.00021592t + 0.87096 x 10 + 4.2092t x 10 per bar where β...

  • Page 78: Calculated Parameters

    Calculated parameters 7828 Density Transmitter Technical Manual CALCULATED PARAMETERS These are also known as Special Functions B.3.1 SPECIFIC GRAVITY Base density (@ Tref) Specific Gravity (SG) Density of water (@ Tref) B.3.2 DEGREES BAUMÉ (Only available when Matrix referral is selected.) ...

  • Page 79: Mass

    7828 Density Transmitter Technical Manual Calculated parameters B.3.5 % MASS (Only available when Matrix referral is selected.) ρ − % mass of product A = ρ − where:- = base density of product A = base density of product B ρ...
  • Page 80 Calculated parameters 7828 Density Transmitter Technical Manual 78285000_AA...

  • Page 81: Introduction

    7828 Density Transmitter Technical Manual Safety Certification Safety Certification INTRODUCTION The paper (hard copy) of this Appendix contains copies of the Safety and EMC Conformity certificates for the 7828. The electronic (Acrobat) version does not include the certificates. Please contact Solartron if you need to have copies of them.
  • Page 82 7828 Density Transmitter Technical Manual Safety Certification 78285000_AC...

  • Page 83: Appendix D - Modbus Communications

    A Modbus network can have only one Master at any one time, with up to 32 Slaves. The 7828 acts as a slave device, and only communicates on the network when it receives a request for information from a Master device such as a computer or a PLC.

  • Page 84: Accessing Modbus Registers

    Modbus Communications 7828 Density Transmitter Technical Manual ACCESSING MODBUS REGISTERS Any device which can drive the RS485 interface on the 7828 can, in theory, access the Modbus registers. In practice, some sort of user interface is required to simplify the process.

  • Page 85: Modbus Implementation

    Modbus register number and consequently cannot be individually read. Registers 47 and 48 within the 7828 allow the Modbus ‘dialect’ to be changed to suit the communicating device if it cannot easily be re-programmed. This is most easily done using ADView’s Register Read/Write tool (see Section 4).

  • Page 86: Modbus Register Assignments

    Modbus Communications 7828 Density Transmitter Technical Manual MODBUS REGISTER ASSIGNMENTS Each register is identified by a unique number, and the list is organised by this number. For each register, the contents are described, along with the data type of the contents.
  • Page 87 7828 Density Transmitter Technical Manual Modbus Communications Modbus Slave address Long integer Hysteresis on alarm output on analog output Long integer D.5.10 Modbus byte order D.3.1 Modbus register size D.3.1 Software type Long integer D.5.11 Hardware type Long integer D.5.12...
  • Page 88 Modbus Communications 7828 Density Transmitter Technical Manual User K1 value for API referral 4-byte float User selected alarm variable Long integer D.5.13 User range (alarm) high value 4-byte float User range (alarm) low value 4-byte float Write-protected copy of K0...

  • Page 89: Pressure, Temperature, Density And Other Units

    7828 Density Transmitter Technical Manual Modbus Communications INDEX CODES This section provides an interpretation of the numerical indices used to represent non- numerical values. D.5.1 API PRODUCT TYPE Used in Register 0. (The user values for K0 and K1 are stored in Registers 182 and 183.)

  • Page 90: Special Function

    Modbus Communications 7828 Density Transmitter Technical Manual D.5.3 SPECIAL FUNCTION Used in Register 6. Index Calculation none % mass % volume Specific Gravity ° Baume ° Brix General Quadratic Equation ° API D.5.4 SPECIAL FUNCTION QUADRATIC EQUATION NAME Used in Register 7.

  • Page 91: Special Function Quadratic Equation Units

    7828 Density Transmitter Technical Manual Modbus Communications D.5.5 SPECIAL FUNCTION QUADRATIC EQUATION UNITS Used in Register 8. Index Name none D.5.6 OUTPUT AVERAGING TIME Used in Register 9. Index Averaging Time none 10 s 20 s 50 s 100 s D.5.7...

  • Page 92: Referral Temperature

    Modbus Communications 7828 Density Transmitter Technical Manual D.5.8 REFERRAL TEMPERATURE Used in Register 27 Index Referral Temperature Lowest temperature value in matrix ↓ Highest temperature value in matrix D.5.9 ALARM COVERAGE Used in Register 29. Bit Pattern Coverage 0x00000001 4 - 20 mA output 1 alarm...

  • Page 93: D.5.12 Hardware Type

    7828 Density Transmitter Technical Manual Modbus Communications D.5.12 HARDWARE TYPE Used in Registers 61. Index Meter Type Advanced Fork D.5.13 USER SELECTED ALARM VARIABLE User in Register 184. Index Variable Line density Base density Temperature Time Period PRT resistance Special Function...

  • Page 94: D.5.15 Status Register Flags

    ST_FRAM1_CSF * FRAM1 CheckSum Fail flag 40000000 ST_FRAM0_ACK FRAM0 ACK/data error 80000000 ST_FRAM1_ACK * FRAM1 ACK/data error * - The status flags marked thus refer to hardware features not present in the 7828. They can safely be ignored. D-12 78285000_AA...

  • Page 95: D.6 Establishing Modbus Communications

    7828 Density Transmitter Technical Manual Modbus Communications ESTABLISHING MODBUS COMMUNICATIONS Using ADView, it is possible to establish which devices are available on the network, and their slave addresses. However, if you are not using ADView, the following procedure can be adopted.
  • Page 96 Modbus Communications 7828 Density Transmitter Technical Manual showing that the transducer is set to 32 bits register size. Thus, by reading the third byte of the response, you can deduce the value of Register 48. c) Send the following message (Read Register 47):...

  • Page 97: D.7 Example Of Direct Modbus Access

    D.7.1 EXAMPLE 1: READING LINE DENSITY (16-BIT REGISTER SIZE) The 7828 is assumed to have been configured with Register Size = 16-bit (Register 48 = 0), and has slave address = 1 The following string will read the line density, which is held in Register 257 (0101...

  • Page 98: D.7.2 Example 2: Reading Line Density (32-Bit Register Size)

    7828 Density Transmitter Technical Manual D.7.2 EXAMPLE 2: READING LINE DENSITY (32-BIT REGISTER SIZE) The 7828 is assumed to have been configured with Register Size = 32-bit (Register 48 = FFFF ), and has slave address = 1 The following string will read the line density, which is held in Register 257 (0101...

  • Page 99: E.1 Conversion Tables

    Reference Data CONVERSION TABLES To convert the left hand column of units into the top row of units, multiply by the factor in the box. E.1.1 LENGTH UNITS inches yards metres inches 0.0278 0.0254 yards 0.9144 metres 39.37 1.0936 E.1.2 MASS UNITS 4.464E-4 0.4536...

  • Page 100: E.1.4 Volume Flow Units

    Reference Data 7828 Density Transmitter Technical Manual E.1.4 VOLUME FLOW UNITS lt/m lt/m 0.000016 0.06 1.44 0.004402 0.264171 0.377388 9.057315 60000 3600 86400 264.1717 15850.30 22643.28 543438.9 16.66666 0.000277 0.073381 4.402861 6.289802 150.9552 0.694444 1.16E-5 0.041666 0.003057 0.183452 0.262075 6.289802 US GPH 227.125...

  • Page 101: E.1.8 Density Units

    7828 Density Transmitter Technical Manual Reference Data E.1.8 DENSITY UNITS kg/m g/cc lb/ft lb/US gal kg/m 0.001 0.062428 0.008345 g/cc 1000 62.428 8.34543 lb/ft 16.0185 0.01602 0.133681 lb/US gal 119.8264 0.119826 7.4805 E.1.9 DYNAMIC VISCOSITY UNITS Pa.s kgf.s/m Slug/ftS lbf.s/ft 0.001...

  • Page 102: E.2 Product Data

    Reference Data 7828 Density Transmitter Technical Manual PRODUCT DATA E.2.1 DENSITY/TEMPERATURE RELATIONSHIP OF HYDROCARBON PRODUCTS Crude Oil Temp Density (kg/m (°C) 738.91 765.06 791.94 817.15 843.11 869.01 894.86 920.87 946.46 742.96 768.98 794.93 820.83 846.68 872.48 898.24 923.95 949.63 747.00 772.89...
  • Page 103 7828 Density Transmitter Technical Manual Reference Data Refined Products Temp. Density (kg/m (°C) 605.51 657.32 708.88 766.17 817.90 868.47 918.99 969.45 1019.87 610.59 662.12 713.50 769.97 821.49 872.00 922.46 972.87 1023.24 615.51 666.91 718.11 773.75 825.08 875.53 925.92 976.28 1026.60 620.49...

  • Page 104: E.2.2 Platinum Resistance Law (To Din 43 760)

    Reference Data 7828 Density Transmitter Technical Manual E.2.2 PLATINUM RESISTANCE LAW (TO DIN 43 760) °C Ohms °C Ohms °C Ohms °C Ohms °F Ohms °F Ohms 80.31 101.91 123.24 144.17 93.03 114.68 82.29 103.90 125.16 146.06 95.21 116.83 84.27 105.85...
  • Page 105 7828 Density Transmitter Technical Manual COSHH Document C.O.S.H.H. Document The form, Number T89004, contained in this Appendix, must be copied and completed whenever a Solartron transducer is to be returned for servicing, calibration or repair to Solartron or one of their agents.
  • Page 106 7828 Density Transmitter Technical Manual COSHH Document 78285000_AA...
  • Page 107 C.O.S.H.H. C.O.S.H.H. Solartron Victoria Road, Farnborough, Hampshire, GU14 7PW, England Telephone: +44 (0)1252 376666 Fax: +44 (0)1252 543854 DOCUMENT HEALTH AND SAFETY CLEARANCE This form must be used when returning 4.5.1 I hereby confirm that the equipment transducers for service/calibration. specified above has not come into contact with any toxic or hazardous substances.
  • Page 108 7828 Density Transmitter Technical Manual COSHH Document 78285000_AA...
  • Page 110 Solartron Mobrey Limited 158 Edinburgh Avenue Slough Berks England SL1 4UE Tel: 01753 756600 Fax: 01753 823589 e-mail: sales@solartron.com www.solartronmobrey.com a Roxboro Group Company Bestobell Mobrey GmbH Deutschland tel: 0211/99 808-0 Solartron Mobrey Ltd China tel: 021 6353 5652 Mobrey sp z o o...

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