JEWELL DX Series User Manual

JEWELL DX Series User Manual

Accelerometer and inclinometer

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DX Series
User's Manual
For DXA-200/100 Accelerometers and DXI-200/100 Inclinometers
Jewell Instruments, LLC
850 Perimeter Road
Manchester, NH 03103
Telephone: 800.227.5955
Email:
Sales@JewellInstruments.com

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Summary of Contents for JEWELL DX Series

  • Page 1 DX Series User’s Manual For DXA-200/100 Accelerometers and DXI-200/100 Inclinometers Jewell Instruments, LLC 850 Perimeter Road Manchester, NH 03103 Telephone: 800.227.5955 Email: Sales@JewellInstruments.com...
  • Page 2: Table Of Contents

    A. About this Manual ........................6 Related Documentation / Applications................. 6 Documentation Conventions ................... 6 Warranty ........................... 7 Product Overview ........................8 A. Introduction to the DX Series ....................8 Features and Options ......................8 Internal Diagram ......................... 9 iii. Typical Applications ......................10 DX Series Installation ......................
  • Page 3 Responses from the DX Series Sensor ..................36 A. ACK and NAK ........................... 36 B. 7 Byte Measurement Output ....................37 DXI Decoding ........................38 DXA Decoding ........................40 Additional Information ......................44 A. Errors and Flash Memory Verification ................44 Troubleshooting ........................
  • Page 4 ....58 Jewell Instruments DX Series User Manual V.81814...
  • Page 5 Jewell Instruments DX Series User Manual V.81814...
  • Page 6: General Information

    • DX Series Interface Platform Application The DX Series Quick Start Guide is an abbreviated version of this manual for fast set up time providing only the minimum of information in order to begin operation with the DX Series Unit. It should not be used as a substitute for this document however could prove useful for those new to the unit or where a reminder set of information is helpful.
  • Page 7: Warranty

    Under Test) , DUT (Device Under Test), DX Series Unit/Sensor. • When referring to the Labview VI, Computer Application, PC, or other receiving body which is the primary destination for data from the DX Series device the following words and phrases may be used: Host, Terminal, Function, Application, Program.
  • Page 8: Product Overview

    Features and Options The DX series sensor enhances the capabilities of the standard servo output of our other product offerings. Each DX series unit has the capability of adjusting several out its output, transmission and data manipulation characteristics to best suit each individual application.
  • Page 9: Internal Diagram

    Department. Internal Diagram The core of the DX Series is based on the same force balance sensors which drive Jewell’s analog sensor offerings. This front back end consists of a torquer, servo, position detector, and various signal conditioning circuits. The analog back end then is fed into the microcontroller and control system as shown in the following Figure 1: DX Series Top Level Hardware Block Diagram.
  • Page 10: Typical Applications

    Automatic Train Position Seismic Platform Leveling Of course the applications for the DX series are not limited to these fields, but have potential anywhere a linear acceleration or incline needs to be accounted for. B. DX Series Installation This section will cover the electrical and mechanical installation of the DX Series digital senor.
  • Page 11 2. Unit Dimensions The sensor is tightly packed within the enclosure to allow for the smallest footprint. Below you can see a partial engineering drawing and its dimensions for the DX series unit. Jewell Instruments DX Series User Manual V.81814...
  • Page 12: Electrical

    A bias network is commonly used in RS485 installations to maintain the line at Mark level when no node is transmitting. The DX series does not require bias, but your RS485 adaptor might – follow the recommendations given for the adaptor.
  • Page 13: Basic Operating Tenants

    Supply V+ 2. Power Supply Requirements The best power supply for the DX series is a linear supply set to any voltage within its operating range of 10 to 30V (Single Sided). Switching power supplies will work as well however it may produce additional noise on the output lines, this noise in most cases will be insignificant.
  • Page 14: Terminal Programs

    With any 3 party software there are limitations to the capabilities. But these have been used in the development and troubleshooting of the DX series in the past so they have some of the key features required for communication and troubleshooting. The ‘$’...
  • Page 15: Temporary Rs485

    RS-485 modes. In short, the DX series unit always starts in RS485 mode while it loads parameters and preforms memory checking functions. After a period of about 30mS, the unit completes its startup routine and determines if it should be operating in RS422 mode.
  • Page 16: Serial Communications

    RESET C. Serial Communications The DX series uses a fixed serial protocol type compatible with RS-232/COM port communication on desktop PC systems. Mark Level is asserted slightly more than 1 character time before the start of a transmission to allow any false start bit due to switching the driver on to clock out of the receiving UART.
  • Page 17 UAID for Y axis is $72. a. Addressing In order to allow for multiple units on a bus when the DX series is operating in 485 mode; each unit on the bus is given an address. The address is a combination of two parts;...
  • Page 18 The last byte in the generalized packet structure is Checksum and serves as a non-parity data corruption detector. It is always one byte long and is included on transmissions to and from the DX series device. Checksum calculations can are DX Jewell Instruments DX Series User Manual V.81814...
  • Page 19: Using Dx Series Commands

    Structures section later in this user’s guide. Using DX Series Commands This section is going to cover the specifics of structuring DX series commands for delivery and execution by the sensor. This includes how the unit verifies each received packet as a valid command via the checksum calculation and other information related to messages to the device.
  • Page 20: Building Command Structures

    4. Building Command Structures Device does not respond to the message if it gets a checksum error. Commands must be sent as continuous strings at the selected baud rate. Any gap within the string Jewell Instruments DX Series User Manual V.81814...
  • Page 21: Full List Of Serial Commands

    This section will cover each command that is accepted by the DX series, its effects, subsequent considerations, and a brief implementation summary. Each command that can be issued to the DX series falls into one of three super classes organized by functional group. The three groups are Configuring Measurement Outputs, Configuring Transmission Parameters, Maintenance and Infrastructure Inputs.
  • Page 22 Averaging Functionality An important set of functions within the DX series unit are the data averaging commands which are used to reduce noise. There are two conditions where the use of the averaging functionality is suggested; when the unit is polled at long intervals in RS485 or in high noise environments.
  • Page 23 When Continuous Averaging is selected, the average is not reset after each output, averaging is always given an exponential weight with the selected time constant for each additional Jewell Instruments DX Series User Manual V.81814...
  • Page 24 Command is equivalent to Set Max Averaging Time Constant in addition to Averaging ON except it does not reset the average. Use for one command configuration of a unit which will need an averaging modification. Set Max Averaging Time Constant and Enable Continuous Averaging. Jewell Instruments DX Series User Manual V.81814...
  • Page 25: Configuring Transmission Parameters

    • Set Unit Address In order to set the UAID to a value each DX series unit includes a set unit address command. This command has a long profile and is similar to the select baud rate command as both the issuing command and its ranged value exist with a single byte.
  • Page 26 LSB reserved portion for axis identification/argument. In order to determine the no axis UAID (for reference) each unit, the 6 bit input to the Assign Unit ID function should be left shifted 2 places and filled with 0’s. Jewell Instruments DX Series User Manual V.81814...
  • Page 27 The commands are used in order to set the value of the 422 emulation parameter TRUE or FALSE within the DX series firmware. 422 Emulation is a software generated state by where the output is constantly driven once the unit identifies the 422 emulation parameter is set to true.
  • Page 28 Output rate when operating in RS 422 mode is controlled by a user definable parameter within the DX series firmware. This extended profile command uses a parameter to define a wide range of values selectable between 0 (by default) and 255 for the 8 bit parameter/character width.
  • Page 29: Maintenance And Infrastructure Inputs

    • Minimum Response Delay (RS-485 Only) Response Delay is an option built into DX series units in order to add additional time between when a unit receives a command and its response. This operation can be applied to both operational modes; however given the perpetual nature of 422 operations each sample would be delayed the same amount resulting in no apparent effect.
  • Page 30 Temporary 485 mode using the BREAK command. Built into the startup sequence of every DX series sensor is a 28 mS window at startup before the unit begins sending data. This window is where a BREAK command addressed to both axes will put the unit in Temporary RS485 mode.
  • Page 31 Ping command is when operating in a terminal interface for inclusive display of ASCII characters. Below is the BROADCAST definition of a ping command: Ping/ENQ Jewell Instruments DX Series User Manual V.81814...
  • Page 32 The RESET command for the DX series is identical allowing for the unit to re-initialize the system operating parameters. Each unit is resets individually and should be treated as such with regards to operating mode or expected behavior.
  • Page 33 001: < Minimum Response Delay Parameter > (Minimum Response Delay setting) 010: < RS 422 Output Period Parameter > (RS422 Output Period setting – 1) Jewell Instruments DX Series User Manual V.81814...
  • Page 34 (minimum response delay) mismatch, etc. So if the baud rate in the editing configuration was not equivalent to that of the Primary configuration, the value of the “X” byte within the configuration vector would be 0x01. This applies for all values in the Jewell Instruments DX Series User Manual V.81814...
  • Page 35 Vector Byte- 9: This value of this byte is the negation of the assigned output parameter. This parameter is only relevant to DX Series Sensor operation when operating in the RS- 422 mdoe. The byte returned by Send Configuration Vector can be converted into a numerical form equivalency output period using the following equation: Jewell Instruments DX Series User Manual V.81814...
  • Page 36: Responses From The Dx Series Sensor

    5. Responses from the DX Series Sensor This section will cover specifics of received packets from your DX series unit. It will also cover the full contents of the 7 byte measurement packet including status conditions and the use of the auxiliary byte.
  • Page 37: Byte Measurement Output

    B. 7 Byte Measurement Output Each DX series output measurement packet has the same 7 byte format. This format is the same from both axes in a dual element sensor bringing each Twin packet response up to 14 bytes.
  • Page 38: Dxi Decoding

    2 MSB’s of D0 are the LSB’s of the data and the rest of D0 are status indicators bits within the Status byte. The DX series unit uses a different data encoding within the18-bit output depending on the base model of Inclinometer or Accelerometer. DXA models use a fractional representation while DXI models use a signed incremental notation to store the measurement information.
  • Page 39 Now that the data has been formatted, we can translate the binary data into an integer count using standard binary positional values, where each count is 1/1000 of a degree. So the 17 bits data above becomes an integer value of: [0][1110 1010][0110 0000] => 60,000 Jewell Instruments DX Series User Manual V.81814...
  • Page 40: Dxa Decoding

    For instance b16 (second MSB) = 0.5, b15=0.25, etc… Below is the equation which shows how the value of any bit in the 18 bit measurement data can be determined. Jewell Instruments DX Series User Manual V.81814...
  • Page 41 To nullify the status bits set last 6 bits of the original 24 to 0. We are maintaining the Left justified 24 bit data variable length for summation and 2’s Jewell Instruments DX Series User Manual V.81814...
  • Page 42 Using standard position values, each location is valued according to the following equation, where only high bit values are used in the summation for final value: ��ℎ������ �� ���� ��ℎ�� ������ ���������������� ������ℎ���� ��ℎ�� 18 ������ �������� 17−�� Jewell Instruments DX Series User Manual V.81814...
  • Page 43 0.12500000000000000 0.75 0.06250000000000000 0.8125 0.03125000000000000 0.84375 0.01562500000000000 0.859375 0.00781250000000000 0.859375 0.00390625000000000 0.86328125 0.00781250000000000 0.87109375 0.00195312500000000 0.87109375 0.00097656250000000 0.872070313 0.00048828125000000 0.872558594 0.00024414062500000 0.872558594 0.00012207031250000 0.872680664 0.00006103515625000 0.872680664 0.00003051757812500 0.872711182 0.00001525878906250 0.872711182 0.00000762939453125 0.872718811 G Jewell Instruments DX Series User Manual V.81814...
  • Page 44: Additional Information

    Checksum passes, the Filter Coefficient area is checked against reference data which was included in the Program Checksum. If a mismatch is found, the coefficients are rewritten and no error would be seen at the next startup. The Calibration Checksum is Jewell Instruments DX Series User Manual V.81814...
  • Page 45: Troubleshooting

    Program Checksum Error is set. B. Troubleshooting Effectively troubleshooting the DX series is done in a few sequential steps. Ensure the device is connected as described in the outline drawing or this manual. Problem: The unit is transmitting, but data is corrupted.
  • Page 46: Guidelines And Effective Output Rate Selection

    C. Guidelines and Effective Output Rate Selection The averaging function/filter built into each DX series unit only a 1-pole response. Therefore the parameters in Set RS422 Output Period command and Set Max Averaging Time Constant or related command must result in the output sample rate being much higher than twice the averaging filter’s cutoff frequency to avoid aliasing.
  • Page 47: Line Resistance Effects

    The DX 200’s line driver is slew- rate limited for RFI reduction, and the voltage drop due to bias current can shift the zero crossings enough to cause transmission errors. Jewell Instruments DX Series User Manual V.81814...
  • Page 48: Appendix A: Condensed Command Set

    AC, 72, C5, 1B $AC $72 $C5 $1B Default UAID X+Y Axis AC, 73, C5, 1A $AC $73 $C5 $1A Standard Averaging OFF: Turns off Averaging and resets average and cancels selection of Continuous mode. Jewell Instruments DX Series User Manual V.81814...
  • Page 49 $AF $72 $E4 $1A Default X+Y Axis -000 AF, 73, E4, 00, F7 $AF $73 $E4 $19 Set Max Averaging Time Constant and Enable Averaging: Functionally identical to executing Set Max Averaging Time Constant and Averaging Jewell Instruments DX Series User Manual V.81814...
  • Page 50: Transmission Parameters

    AC, 73, C3, 1C $AC $73 $C3 $1C Default X Axis -010 AC, 71, C3, 1E $AC $71 $C3 $1E Default Y Axis -001 AC, 72, C3, 1D $AC $72 $C3 $1D RS-422 Emulation OFF: Jewell Instruments DX Series User Manual V.81814...
  • Page 51 DXA Output rate Table: Hexadecimal String Realterm Copy and Paste Generic AF, "UAID", E2, “Period”, “Checksum" Default X+Y Axis – 90 Hz AF, 73, E2, 00, F9 $AF $73 $E2 $00 $F9 Jewell Instruments DX Series User Manual V.81814...
  • Page 52: Maintenance & Infrastructure

    Realterm Copy and Paste Generic AC, “UAID”, 03, “Checksum” Default X+Y Axis AC, 73, 03, DC $AC $73 $03 $DC Broadcast X+Y Axis AC, 03, 03, 4D $AC $03 $03 $4D Allow Update: Jewell Instruments DX Series User Manual V.81814...
  • Page 53 Default X+Y Axis : AC, 73, B3, 2C $AC, $73, $B3, $2C Max Avg. Time Const. Note: Returned values are from the editing segment of the UUT. Send Configuration Vector: Hexadecimal String Realterm Copy and Paste Jewell Instruments DX Series User Manual V.81814...
  • Page 54 The Acknowledge message is generated after command executes. Thus if Unit ID is changed, the Acknowledge from Update Configuration will contain the new UAID. The Acknowledge from Set Minimum Response Delay reflects the new delay setting. Jewell Instruments DX Series User Manual V.81814...
  • Page 55: Appendix B: Technical Documentation

    Appendix B: Technical Documentation Jewell Instruments DX Series User Manual V.81814...
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This manual is also suitable for:

Dxa-100Dxa-200Dxi-100Dxi-200

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