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CMG-3ESP

Operator's Guide

Document No: MAN-ESP-0001

Issue G, February 2016

Designed and manufactured by
Güralp Systems Limited
3 Midas House, Calleva Park
Aldermaston RG7 8EA
England

Summary of Contents for CMG-3ESP

Page 1: ...CMG 3ESP Operator s Guide Document No MAN ESP 0001 Issue G February 2016 Designed and manufactured by G ralp Systems Limited 3 Midas House Calleva Park Aldermaston RG7 8EA England...

Page 2: ...ut types 3 2 1 3 Sensor response 4 3 Installing the 3ESP 5 3 1 First encounters 5 3 1 1 Unpacking 5 3 1 2 Connections 6 3 2 Installation notes 8 3 3 Installing in vaults 9 3 4 Installing in pits 13 3...

Page 3: ...1 3 Control commands 29 5 1 4 Outputs 29 6 Inside the 3ESP 30 6 1 The sensors 30 6 2 Locking and unlocking 30 6 2 1 Manual control 30 6 2 2 Automatic control 31 6 3 The feedback system 35 6 3 1 Hybri...

Page 4: ...ngle indicates a chance of damage to or failure of the equipment if the caution is not heeded Note A blue circle indicates indicates a procedural or advisory note 1 3 Manuals and Software All manuals...

Page 5: ...CMG 3ESP Preliminary Notes Putting these together into a single example System prompt user input with variable parameters MAN ESP 0001 2 Issue G February 2016...

Page 6: ...pe records suitable for modern earthquake mechanism analysis The 3ESP is designed for mounting on a hard near horizontal surface well coupled to the bedrock After levelling and orienting the case you...

Page 7: ...factors The CMG 3ESP can be supplied in several forms besides its standard configuration The CMG 3ESP Compact is internally identical to the standard 3ESP but has a different arrangement of components...

Page 8: ...r own pin out specification 2 1 3 Sensor response The 3ESP can be supplied with a response which is flat to velocity from 100 Hz to any of 0 1 Hz 10 s 0 033 Hz 30 s 0 016 Hz 60 s 0 01 Hz 100 s or 0 00...

Page 9: ...d Control Unit HCU for monitoring sensor outputs and calibration if ordered 10 pin connector for your power lead Calibration and installation sheet Assuming all the parts are present stand the seismom...

Page 10: ...shielded twisted pair cabling must be used for the sensor outputs control lines and power supply If you need to make up a suitable cable you should confirm the cable type with G ralp Systems Connecto...

Page 11: ...p a suitable cable to connect a 12 V power source to the 10 pin connector on the breakout box spare 10 pin mil spec connectors are provided for this purpose Using a 12 V 25 Ah sealed heavy duty lead a...

Page 12: ...s To achieve this the seismometer and its emplacement need to be considered as a mechanical system which will have its own vibrational modes and resonances These frequencies should be raised as high a...

Page 13: ...s This will take around four hours from the time installation is completed If you require long period recording you should re zero the instrument after this time 3 3 Installing in vaults You can insta...

Page 14: ...of the instrument in turn until the bubble in the spirit level lies entirely within the inner circle The instrument can operate with up to 2 of tilt but with reduced performance 7 The feet are mounted...

Page 15: ...each mass to be locked and unlocked Locate the socket corresponding to the vertical sensor mass Otherwise skip to step 16 Remove the pressure cap from the socket 11 Carefully insert a 3 mm hex driver...

Page 16: ...re Alternatively if you are using a DM24 digitizer and a DCM navigate to the Actions Digitizer Setup Port x page for the digitizer and click on the Centre instrument button at the bottom of the page I...

Page 17: ...ic pit Depending on the time and resources available this type of installation can suit all kinds of deployment from rapid temporary installations to medium term telemetered stations Ideally the senso...

Page 18: ...m across and shift it to compact the sand and provide a near level surface 3 Placing a granite plinth on a sand layer increases the contact between the ground and the plinth and improves the performan...

Page 19: ...he box down to the surface to exclude draughts Alternatively if a box is not available cover the instrument with fine sand up to the top 8 The sand insulates the instrument and protects it from therma...

Page 20: ...reparation Finally many pit installations have a large space around the seismometer covered with a wooden roof Large air filled cavities are susceptible to currents which produce lower frequency vibra...

Page 21: ...y a mixture of 3 mm grade angular coarse grit with around 30 medium grit gives good results Moisten the packing material in the hole and ram firm 4 Lower the instrument to the bottom of the hole but w...

Page 22: ...f the instrument To remind you of this the sensitivities are given as 2 single ended sensitivity in each case Mass Position Output The sensitivity of the mass position outputs to acceleration in volts...

Page 23: ...merator polynomial giving the zeros of the transfer function and pm are the roots of the denominator polynomial giving the poles of the transfer function In the calibration pack G is the sensitivity g...

Page 24: ...esponse 4 1 3 Obtaining copies of the calibration pack Our servers keep copies of all calibration data that we send out In the event that the calibration information becomes separated from the instrum...

Page 25: ...form calibration either using a G ralp DM24 digitizer which can generate step and sinusoidal calibration signals or by feeding your own signals into the instrument through a hand held control unit Bef...

Page 26: ...ing The streams should display the calibration signal combined with the sensors own measurements If you cannot see the calibration signal zoom into the Waveview using the scaling icons at the top left...

Page 27: ...ill in the sensor response code for your sensor according to the table below Instrument Type should be set to the model number of the sensor 11 If the file calvals txt exists in the same directory as...

Page 28: ...uality results at low frequency it will save computation time to use data collected at a lower sample rate although the same information is present in higher rate streams they also include a large amo...

Page 29: ...into the system through a hand held control unit The unit includes a switch which activates the calibration relay in the seismometer and 4 mm banana sockets for an external signal source As above the...

Page 30: ...this measurement for several tilt angles 4 For the vertical sensor the input acceleration is given by a g sin whilst for the horizontal sensor it is a g 1 cos 5 Calculate the input acceleration for e...

Page 31: ...and repeats it at the connector on the side for connection to further equipment The hand held control unit can be sited up to 50 m from the breakout box 5 1 1 The meter The meter at the top of the un...

Page 32: ...use You should not attempt to move the instrument without re locking the masses To lock the sensor masses on a sensor with automatic mass control press the ENABLE and LOCK UNLOCK switches down simulta...

Page 33: ...ames so as to relieve strain on the support hinges This locking is performed by a small motor driven clamp in response to a signal from the surface controller unit Before using the instrument the boom...

Page 34: ...USY LED will flash you can use this for diagnostic purposes See the description of each command for full details When no command is active i e all three lines are high the control microprocessor goes...

Page 35: ...ge but goes out briefly between stages allowing you to follow the progress of the lock 6 2 2 2 UNLOCK remote control option This command unlocks the sensor masses and prepares the instrument to begin...

Page 36: ...s stage will take longer than stage 2 since it must move the mass all the way from its end stop As the mass nears the centre the control circuit spaces out the pulses 6 The E W component is checked an...

Page 37: ...pulses cause the mass to overshoot the central position and a second group of pulses in the opposite direction is applied to bring it into line The E W component follows in the same way All three mas...

Page 38: ...the forward and feedback paths Force feedback seismometers of this type rely on the assumption that the force transducer produces a field of constant strength The magnetic circuit and magnet pole ass...

Page 39: ...ies The velocity response of a conventional response system is defined by a transfer function identical to that of a conventional long period sensor with a damping constant of 0 707 1 2 The seismomete...

Page 40: ...CMG 3ESP Inside the 3ESP MAN ESP 0001 37 Issue G February 2016...

Page 41: ...A Velocity ve vertical channel P Calibration signal all channels B Velocity ve vertical channel R Calibration enable Z channel C Velocity ve N S channel S Calibration enable N S channel D Velocity ve...

Page 42: ...ber is 12 10P where the is defined by the manufacturer Suitable mating connectors have part numbers like 12 10S Pin Function A 0 V B 12 V DC supply C not connected D not connected E not connected F no...

Page 43: ...Mass position sensitivity 1000 V m s2 Mass locking and unlocking manual optional remote operation Mass centring automatic MPU controlled Sensors 3 orthogonal each 0 180 kg Lowest spurious resonance ab...

Page 44: ...d be 30 s 0 033 Hz Temperatures below 20 C may be accommodated with additional care Please consult G ralp Systems for advice Because centring locking and unlocking consume varying amounts of power it...

Page 45: ...cument 2006 02 21 C Updates added revision history 2006 11 15 D Redrawn diagrams 2011 03 18 E Changes to vault procedures formatting updates 2011 08 23 F Corrections to connector pin out 2016 02 18 G...

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