Related Manuals for Güralp CMG-5TD
Summary of Contents for Güralp CMG-5TD
- Page 1 CMG-5TD Digital Accelerometer Operator’s Guide Document No: MAN-050-0005 Issue: D – April 2013 Designed and manufactured by Güralp Systems Limited 3 Midas House, Calleva Park Aldermaston RG7 8EA England...
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Page 2: Table Of Contents
CMG-5TD Digital Accelerometer Contents Table of Contents 1 Preliminary Notes......................4 1.1 Proprietary Notice..................... 4 1.2 Warnings, Cautions and Notes.................4 1.3 Manuals and Software....................4 1.4 Conventions......................4 2 Introduction........................5 3 Quick start........................6 3.1 Unpacking and packing.....................6 3.2 Initial check-out......................7 4 Setting the gain...................... - Page 3 CMG-5TD Digital Accelerometer Preliminary Notes 5.9.2 Output control....................17 5.9.3 Triggering......................20 5.9.4 Baud rates....................... 23 5.9.5 Data flow......................23 5.9.6 Buffer Memory Usage..................28 6 Calibration........................29 6.1 The calibration pack....................29 6.1.1 Poles and zeroes.....................29 6.1.2 Frequency response curves................30 6.1.3 Obtaining copies of the calibration pack............31 6.2 Calibration methods....................32...
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Page 4: Preliminary Notes
CMG-5TD Digital Accelerometer Preliminary Notes Preliminary Notes Proprietary Notice The information in this document is proprietary to Güralp Systems Limited and may be copied or distributed for educational and academic purposes but may not be used commercially without permission. Whilst every effort is made to ensure the accuracy, completeness and usefulness of the information in the document, neither Güralp Systems Limited nor any employee assumes responsibility or is liable for for any... -
Page 5: Introduction
CMG-5TD and are user-accessible and adjustable via adjusting screws on the top cap of the instrument. A GPS receiver is used to provide accurate time-stamps for seismic data. The GPS receiver is attached to the CMG-5TD via a supplied 20 metre cable. -
Page 6: Quick Start
Quick start Unpacking and packing The CMG-5TD accelerometer system is delivered in a single cardboard box with foam rubber lining. The packaging is specifically designed for the CMG-5T system. Whenever transported, the CMG-5TD system should be packed in its original shipping container. -
Page 7: Initial Check-Out
Attach the levelling baseplate to the base of the CMG-5TD using the screws provided. Set the CMG-5TD onto a flat surface. Using the large hex screws on the baseplate in conjunction with the bubble level, level the instrument. Connect the CMG-5TD directly to the PC using the supplied power/data cable Switch on the power supply. - Page 8 CMG-5TD Digital Accelerometer Quick start 7. The data streams will appear in the right-hand frame. 8. The Stream IDs are six-character strings which uniquely identify each instrument, component and sample rate. (There may be up-to four different sample rates per channel) The stream ending in ‘00’ contains status information from the digitiser.
- Page 9 11. While viewing the time series from all three components in a WaveView window, gently tap the CMG-5TD, and observe the response of all three components. If the CMG-5TD passes this initial basic test, then you may proceed to install the system (see the Operation section of this User’s Guide).
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Page 10: Setting The Gain
Caution: The CMG-5TD include components which can be damaged by electrostatic discharge (ESD). Always work on a properly grounded dissipative surface and wear a suitable grounded wristband. -
Page 11: Jumper Configuration For Low Gain Operation
CMG-5TD Digital Accelerometer Setting the gain Lift the lid and the attached electronics vertically out of the cylindrical body • and disconnect the ribbon cable at either end, noting the orientation of the cable. Looking down into the body of the instrument, you will see a small printed circuit board mounted on an aluminium disc. -
Page 12: Jumper Configuration For High Gain Operation
CMG-5TD Digital Accelerometer Setting the gain Jumper configuration for high gain operation Arrange the jumpers as in the picture below: Reassembly Once the desired gain selection has been made, reconnect the ribbon cable and gently lower the lid onto the instrument, taking care not to knock the electronic assemblies or snag any cables. -
Page 13: Operation
Attach the upper portion of the levelling plate to the base of the CMG-5TD using the screws provided. Finally, attach the CMG-5TD to the mounting base by joining the two portions of the levelling plate using the socket-cap screws provided. -
Page 14: Installation In Hazardous Environments
8 mm ring tag or via the mounting bolt itself. Orientation Use the handle and north indicator inscribed in the handle to orient the CMG-5TD. Levelling Use the large socket-cap screws to level the CMG-5TD. Remove the upper portion of the mounting plate, then tighten down the concrete bolt, securing the base. -
Page 15: Offset Adjustment
CMG-5TD Digital Accelerometer Operation Offset adjustment When the instrument is installed in it’s final position and correctly aligned, the approximate level should be checked using the bubble level on the top of the casing. The bubble should lie completely within the scribed ring. To check the DC offsets, read the RIC value for each acceleration stream in the SCREAM window. -
Page 16: Configuration And Control Using Scream
Scream is a free software application for Windows and Linux PCs. For more information and download details, please see www.guralp.com/scream/. The CMG-5TD may be configured using Scream's graphical interface. Right- click on the digitiser's icon in the source tree and select “Configure” from the pop-up menu. -
Page 17: System Id
CMG-5TD Digital Accelerometer Operation Parameters from most of the commands are stored to the battery-backed CMOS and only take effect when the digitiser is rebooted. When you click the “Download” button from the digitiser configuration interface, the parameters you have chosen are transferred to the digitiser and it is automatically rebooted. - Page 18 CMG-5TD Digital Accelerometer Operation sampling rate lower than the one above but the rate must be achievable using decimation by a factor of 2, 4, 5, 8 or 10. Each drop-down menu offers a list of the rates that are permitted, given the sampling rate on the line above it.
- Page 19 CMG-5TD Digital Accelerometer Operation 00 is the digitiser status stream (notice that there is no sample rate) • (Odd tap numbers (1, 3, 5, …) are used for streams from a second instrument.) For each tap there are two rows of check-boxes where the user can tick either triggered or continuous data outputs.
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Page 20: Triggering
CMG-5TD Digital Accelerometer Operation 5.9.3 Triggering Once at least one box is checked for triggered output, the Triggering box and tab are activated. If you set triggering, you must also set the parameters for the trigger criteria. MAN-050-0005 Issue D - April 2013... - Page 21 CMG-5TD Digital Accelerometer Operation The Data Source button selects the tap (streams) that will be evaluated for triggers for both the STA/LTA and the Level triggers. In general, it is not advisable to use an STA/LTA trigger directly from broadband data. The Bandpass Filter button allows the user to select from a set of standard bandpass filters from a pull-down menu (a full list of options is given later in the STA/LTA chapter).
- Page 22 CMG-5TD Digital Accelerometer Operation Level triggering parameters: The user specifies the Data Source, channels and levels by clicking on them, similar to the STA/LTA settings. The levels are specified in counts. MAN-050-0005 Issue D - April 2013...
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Page 23: Baud Rates
CMG-5TD Digital Accelerometer Operation 5.9.4 Baud rates This tab allows the setting of the line speed for the main serial output. It is possible to set different rates for transmission and reception but this is rarely required with modern communications equipment. Ticking the “Identical Tx/Rx rates”... - Page 24 CMG-5TD Digital Accelerometer Operation DIRECT not at all ( mode). • buffering modes Separate from these modes are , which tell the unit what to do when its Flash memory becomes full: either carry on, overwriting the oldest data held, or •...
- Page 25 CMG-5TD Digital Accelerometer Operation Block Recovery Protocol: a temporary RAM buffer always holds the last 256 blocks generated, and if a client fails to receive a block it can request its retransmission. If you expect breaks in communication between the instrument and its client to last...
- Page 26 CMG-5TD Digital Accelerometer Operation FILING If your digitizer is in mode, Scream! will displays a slider at the bottom of the tab. Moving this slider changes the interval between heartbeat blocks. You can tell Scream! to download new data automatically whenever it receives a...
- Page 27 CMG-5TD Digital Accelerometer Operation 5.9.5.5 FIFO (First In First Out) FILING Instructs the digitizer to begin writing blocks to Flash memory as for mode, but also to transmit data to clients. Data are transmitted in strict order, oldest first; the digitizer will only transmit the next block when it receives an explicit acknowledgement of the previous block.
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Page 28: Buffer Memory Usage
CMG-5TD Digital Accelerometer Operation Some software packages (most commonly Earthworm) cannot handle blocks being ADAPTIVE received out of time order. If you are using such a package, mode will not work, and may crash the software. 5.9.6 Buffer Memory Usage 5.9.6.1 RE-USE / RECYCLE... -
Page 29: Calibration
Acceleration Output (Differential) : The sensitivity to acceleration at 1 Hz, in volts per . Because the CMG-5TD uses a balanced differential output to connect to the digitiser, the signal strength as measured between the +ve and –ve line will be twice the true sensitivity of the instrument. - Page 30 CMG-5TD Digital Accelerometer Calibration In this equation, is the acceleration output sensitivity (gain constant) of the instrument. • This relates the actual output to the desired input over the flat portion of the frequency response. is a constant which is evaluated so that is dimensionless and has a A ×...
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Page 31: Frequency Response Curves
CMG-5TD Digital Accelerometer Calibration 6.1.2 Frequency response curves The frequency response of the CG-5TD is described in the normalised amplitude and phase plots provided. The response is measured at low and high frequencies in two separate experiments. Each plot marks the low-frequency and high-frequency cut- off values (also known as –3 dB or half-power points). -
Page 32: Calibration Methods
CMG-5TD Digital Accelerometer Calibration The server will reply with the calibration documentation in Microsoft Word format. The body of your e-mail will be ignored. Calibration methods Three common calibration techniques are available: Injecting a step current allows the system response to be determined in the •... - Page 33 CMG-5TD Digital Accelerometer Calibration In Scream!'s main window, right-click on the digitiser's icon and select Calibration Control..Open the pane. Select the calibration channel corresponding to the instrument, and choose Broadband Noise. Select a suitable duration and amplitude, and click Inject now.
- Page 34 CMG-5TD Digital Accelerometer Calibration If the returning signal is saturated, retry using a calibration signal with lower amplitude, until the entire curve is visible in the Waveview window. If you need to scale one, but not another, of the traces, right-click on the trace and select Scale..
- Page 35 CMG-5TD Digital Accelerometer Calibration This runs a script, bbnoisecal, which prompts you for sensor calibration parameters for each component you have selected. Most data can be found on the calibration sheet for your sensor. Under Instrument response , you should fill in the sensor response code for your Instrument Type sensor, according to the table below.
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Page 36: Sensor Response Codes
The table below shows the correct value to use in the field of the bbnoisecal dialogue, depending on the type of your instrument. Sensor Sensor type code Units (V/A) CMG-5TD, DC – 50 Hz response DC-50 CMG-5TD, DC – 100 Hz response CMG-5_100 CMG-5TD, DC – 200 Hz response CMG-5_200... -
Page 37: Connector Pin-Outs
CMG-5TD Digital Accelerometer Connector pin-outs Connector pin-outs DATA This is a standard 10-pin “mil-spec” plug, conforming to MIL-DTL-26482 (formerly MIL-C-26482). A typical part-number is 02E-12- 10P although the initial “02E” varies with manufacturer. Suitable mating connectors have part-numbers like ***-12-10S... -
Page 38: Gps
CMG-5TD Digital Accelerometer Connector pin-outs This is a standard 10-pin “mil-spec” plug, conforming to MIL-DTL-26482 (formerly MIL-C-26482). A typical part-number is 02E-12-10P although the initial “02E” varies with manufacturer. Suitable mating connectors have part-numbers like ***-12-10S available from Amphenol, Cannon other manufacturers. -
Page 39: Analogue Connector
CMG-5TD Digital Accelerometer Connector pin-outs Analogue connector This is a standard 19-pin “mil-spec” socket, conforming to MIL-DTL-26482 (formerly MIL-C-26482). A typical part-number is 02E-14-19S although the initial “02E” varies with manufacturer. Suitable mating connectors have part-numbers like ***-14-19P and are available from Amphenol, ITT Cannon and other manufacturers. -
Page 40: Specifications
CMG-5TD Digital Accelerometer Specifications Specifications Transducer type Accelerometer Standard output band DC – 100 Hz Output sensitivity 4 g, 2 g, 1 g, 0.5 g, 0.1 g Corresponding high gain outputs 0.4 g, 0.2 g, 0.1 g 0.05 g, 0.01 g Peak analogue output ±10 V differential... -
Page 41: Revision History
CMG-5TD Digital Accelerometer Revision History Revision History 2002-06-05 Initial release 2002-10-21 Revision for firmware updates 2003-01-22 Revision for firmware updates 2012-04-17 Reformatted and revised MAN-050-0005 Issue D - April 2013...
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