System Interface Module (SIMx) User`s Manual - Micro
Contents
1. information to the dropper controller on the position and velocity of the cart Information on the relative position of the test mass to the cart during free fall is provided by comparing the interferometric fringe output position of the test mass with the shaft encoder information position of the cart The dropper controller uses this information to determine whether to maintain increase or decrease current to the motor to achieve the appropriate relative position of the cart and the test mass This feedback system is a conventional analog servo system At the end of the drop the cart slows gently catching the test mass During a measurement the TRIG signals are sent to the dropper automatically by the software In OSC oscillation mode the cart slowly moves the test mass up and down to generate slow and uniform optical fringes in the interferometer An oscilloscope attached to Analog Fringes Out in the Status portion of the SIMx can be used to measure the fringe amplitude The position of the cart is indicated by the CART POS LEDs To automatically stop OSC mode simply press TRIG or DROP and the cart will stop at the bottom of the next cycle Operation Using the SIMx Reset Default mode of the dropper controller at power up is RESET When in RESET mode the dropper cannot be made to oscillate lift or drop Pressing RESET at any time will stop power to the dropper motor System Interface Module Version 1 01 Rele2. ENNA 10MHz 10MHz SINE TIL Figure 2 7 Rear View of the SIM left side connectors AC Input The SIMx is designed for universal AC input power 100 240VAC 50 60Hz Auxiliary AC Outputs Three auxiliary AC outputs are provided for external components system computer ion pump power supply etc GPS Antenna When connected to a GPS antenna the SIMx can use the satellite information to synchronize with g software setting system clock time and providing location information and it can discipline the internal rubidium clock to a cesium based perfect 10MHz When lock is achieved and LED on the front panel with illuminate WARNING The clock will be disciplined to 10MHz only after GPS lock is attained and then while the SIMx is powered on even if GPS lock is lost If the system is restarted the clock will revert to its own internal frequency It is important to use the correct frequency in the g software Advanced Settings Setup 2 8 System Interface Module Version 1 01 Release Date 05 October 2011 10MHz Outputs Both sine wave and TTL square wave outputs of the 10MHz clock are available The TIA card in the ex Box unit uses the 10MHz sine wave SUPER SPRING LEVEL APD ENCODER MOTOR DROPPER COMPUTER ML 1 ML 1 ANALOG TRIGG ER uc x ER TRIGGER LASER LASER e ES OUT OUT TOCK MODE USB RERUM Figure 2 8 Rear View of the SIM right side connectors Components Connections Connections to the Supers
3. October 2011 Superspring Controller Theory of Operation SUPER SPRING SERVO ZERO O SPRING COIL POSITION CURRENT Figure 2 2 Superspring Controller The Superspring is an electro mechanical system designed to isolate the reference mass from any vertical motion typically due to micro seismic noise during the measurement A position feedback linear actuator coil magnet system maintains the position of the reference mass and a motor attached to the top of the mainspring as well as an aneroid wafer assembly keep the position fixed over long period changes in temperature and or local gravity A sphere detector system provides information on the position of the reference mass relative to the mainspring support system An infrared LED and a photo detector are mounted opposite each other inside the mainspring support housing A sphere attached to the bottom of the mass focuses the light from the LED onto the detector which transmits the resulting signal to a sphere signal preamplifier Changes in temperature or moving the gravity meter to a new location that has a significantly different local gravity can change the length of the main spring In some cases this change may even move the sphere signal off of the small detector The position of the test mass can be adjusted by System Interface Module Version 1 01 Release Date 05 October 2011 moving the top of the main spring with a small DC motor with a very large gea
4. System Interface Module SIMx User s Manual Version 1 01 DECEMBER 2012 Copyright 2011 Micro g LaCoste All Rights Reserved Reproduction adaptation or translation without prior written permission is prohibited except as allowed under the copyright laws Publication Number 115 090 002A Version 1 01 05 October 2011 Applicable Products Micro g LaCoste FGL FG5 Absolute Gravimeter Disclaimer The information contained in this document is subject to change without notice Micro g LaCoste makes no warranty of any kind Micro g LaCoste shall not be liable for errors contained herein or for incidental or consequential damages in connection with the furnishing performance or use of this material Contact Micro g LaCoste 1401 Horizon Avenue Lafayette Colorado 80026 USA Tel 303 828 3499 Fax 303 828 3288 E Mail info microglacoste com Website www microglacoste com Table of Contents Section Page Ts sild sie 1752 07 AAA AAA AA NAA AONE 1 1 bli UA 1 1 Optional Tele g Remote Gravimeter Operation Package 1 1 2 System Interface Module peli iine nin mm maini nunu kin rais dd EE NR ONERE 2 1 Dropper Controller staadiumid COSI dd uU Tax usse EMINET uU UNE 2 1 Theory Of ODGOFSEIDEL lintmaki o RERO c c NR RR RD ER 2 1 Operation Using the SIND iassessunxknxg d ad Kod eaa d RA RS RR 9 c en NAR wad a d 2 2 Superspririg Controller su ida najal hx hd ta a ad Da Xd GORGE AGUA a A ka
5. TIONS kaa 2 9 ML 1 Laser Mode and Lock MOOR ui cic i ha iR OR DR NR c d cR 2 10 A alog Fringes DW ies ic aen d cia ia a en en 2 10 USB CONNMEGCEON ii IIIA 2 10 Most system electronics are housed in the System Interface Module SIMx This unit replaces the separate Patch Panel Superspring Controller Dropper Controller and Power Supply modules of previous FG5 systems Functionally the front panel of the SIMx can be divided into five sections The Dropper Controller The Superspring Controller e Rubidium Clock 10MHz source status e The Auto Level Controller not currently implemented The analog signal Patch Panel to the g software Dropper Controller DROPPER RESET M F TRIGGER DROP 3 TRIGGER OBJECT CART OUT POSITION POSITION Figure 2 1 Dropper Controller Theory of Operation The dropper controller can operate the dropping chamber in two modes DROP and OSC DROP Mode In DROP mode a manual press of the TRIG causes the motor in the Dropping Chamber to lift the cart and test mass to a System Interface Module 2 1 Version 1 01 Release Date 05 October 2011 OSC Mode specified height This is the start of the drop Another press of the TRIG button will initiate a drop During a drop the motor drives the cart test mass assembly by turning a pulley and stainless steel drive belt which is attached to the cart Attached to the shaft is an optical shaft encoder that provides accurate
6. ar View of the SIM left side connectors wwmaaaananananananuaaananzanawa 2 8 Figure 2 8 Rear View of the SIM right side connectors nnnrrnnnnn vanana nunna 2 9 ii Table of Contents Version 1 01 Release Date 05 October 2011 Table of Contents Version 1 01 Release Date 05 October 2011 1 INTRODUCTION DESIGN m 1 1 Optional Tele g Remote Gravimeter Operation Package sseesss 1 1 Design The X version of the System Interface Module SIMx is a flexible system designed to run the FGL FG5 and FG5 X absolute gravimeters This system provides many different functions It interfaces with the system controller computer providing analog and digital input and output it controls the dropping chamber and Superspring and it houses the 10MHz rubidium clock and automatically syncs it with GPS It communicates via USB directly with the g software Absolute Gravity Data Acquisition and Processing Software g software described in detail in the g software Absolute Gravity Data Acquisition And Processing Software User s Manual Optional Tele g Remote Gravimeter Operation Package The Tele g Remote Gravimeter Operation Package is optional software and hardware that allows the FGL FG5 X to be operated remotely via the internet See the Tele g Remote Gravimeter Operation User s Manual for additional information The Tele g program runs in add
7. ase Date 05 October 2011 Drop Pressing DROP will put the dropper in drop mode In this mode pressing TRIG will Cart at the bottom Pressing TRIG will lift the cart to the top of its travel Cart at the top Pressing TRIG will initiate the drop sequence in which the cart places the test mass in freefall and then gracefully catches it at the bottom The dropper should be in DROP mode for data acquisition The CART POS LEDs indicates the position of the cart OSC Pressing OSC will put the dropper in oscillation mode In this mode pressing TRIG will Cause the cart to slowly and repeatedly go up and down to generate slow fringes for optical alignment purposes Pressing TRIG or DROP will stop OSC mode at the end of the current cycle BNC Outputs for Dropper Controller There are three BNC outputs for the Dropper Controller TRIG OUT sends out a logic pulse when the drop has been initiated This is normally used to trigger the Time Interval Analyzer card in the system controller computer OBJECT POS can be used to read out the position of the test mass relative to the cart during a drop As the distance increases during the freefall portion of the drop the voltage output increases The voltage drops back to zero when the test mass is caught by the cart at the end of the drop CART POS can be used to read out the position of the cart relative to the dropping chamber System Interface Module 2 3 Version 1 01 Release Date 05
8. coil magnet mechanism Ideally after the spring has come to equilibrium this is constant at zero See the FG5 Absolute Gravimeter User s Manual for details System Interface Module 2 5 Version 1 01 Release Date 05 October 2011 MICR of ACOSTE Figure 2 3 Auto Leveling Portion of System Interface Module Note that automatic tilt monitoring correction is currently disabled in the FG5 X Software Interfaces g INPUTS The software interface to the g software Absolute Gravity Data Acquisition and Processing Software is shown in Figure 2 4 Refer to the g software Absolute Gravity Data Acquisition And Processing Software User s Manual for information on the software 2 6 System Interface Module Version 1 01 Release Date 05 October 2011 Mic RO g INPUTS LACOSTE ION PUMP LASER 1F Figure 2 4 The Tele g and g software Interface The BNC connectors in this section are all inputs The Ion Pump and Laser inputs are used in the g Software for diagnostic purposes AUX 1 and AUX 2 are auxiliary inputs for user defined functions and or future upgrades For past FG5 users note that the rest of the connections barometer triggers Superspring sphere are now all connected internally Rear Connections Figure 2 5 Rear View of the SIM Figure 2 6 Rear View of the SIM System Interface Module 2 7 Version 1 01 Release Date 05 October 2011 MICR oe ACOSTE 100 240 VAC IN 6A AUXILIARY AC OUT GPS ANT
9. ion from the software to the Dropper Controller and Superspring controllers System Interface Module Version 1 01 Release Date 05 October 2011 System Interface Module Version 1 01 Release Date 05 October 2011 2 11
10. ition to the g software and it allows the monitoring and control of a large portion of the system components These components include Monitor Dropper Controller Servo signal Dropper Mode e Superspring position Superspring Mode Interferometric fringe amplitude measurement In addition the Tele g Remote Gravimeter Operation system allows the following parameters to be adjusted through the Tele g interface Resetting the tilt position and thus verticality back to zero Changing the Superspring position e Enabling Disabling the Superspring servo Changing the dropper controller mode Introduction 1 1 Version 1 01 Release Date 05 October 2011 1 2 Introduction Version 1 01 Release Date 05 October 2011 2 SYSTEM INTERFACE MODULE Dropper Controler AM Mmmm a NE 2 1 Theory of Operati ai afa RE p GE AU EE D RE Vua 2 1 Operation Using Ehe SIMM uxaesu n ak RED oan EE wien RR a d nnd ain eral 2 2 S perspring COE FON BI e usando idealo ok a DE a rc D NE V D a 2 4 Theory of Operation REPE m 2 4 Operation Using the SIM Sisuesexobex e nsoasan ctrev d Rana E nPE rbERUF EFE VD IM rREN MN UF ax SUME 2 5 System UA AAA ER 2 5 Software Interfaces g INPUTS mia 2 6 Rear Con IAA 2 7 An ia AA 2 7 A Xiliary AC OUTPUTS AAA 2 8 GPS Antemna aa aaa a aaa a a a a aaa aaa 2 8 TOMHZ OUtpUts 5 resa er ke terr rh n nsu a aa aa aaa dam 2 9 Components Connections reani i ee ene eee ness nenne 2 9 Trigger CONMEC
11. lk vaala a 2 4 Theory of Operation usssaxsasauzap eva bXa dA Abu ER LEER QUK AR UC VOR C CURE d 2 4 Operation Using the SIM assassinated 2 5 Systemi Level ii 2 5 Software Interfaces g INPUTS sisswsincscennadscunedecumsadsadidoumediandvandncdstentecens 2 6 Rear Conrfiectlons sone n ecrit nnn naw x NER eR UE RR a RO OR TR UR K ER ER IR e vin eee 2 7 AC IANDUL itta andekam avada aaa ei CR ke END E CER REN RR RAD CT 2 8 Auxiliary AC OUEDUES an a vimm nii aaa DOCE inane URNA a CUR ki la 2 8 GPS Antenna sari nnis gaala ama gn curru mensus cu Ur Kent D E E ER 2 8 10MAZ OULD UES ia 2 9 Components Connections nnnnnununnnanannnnnneena annan nen nn annae 2 9 Trigger CONNECTIONS MAANA 2 9 ML 1 Laser Mode and Lock Mode 1 errore hr rra ohnehin ran n i 2 10 Analog Fringes Tsai vasemas boa s n dalate 2 10 USB ConriectiODn ctos avad 48 ne ion n xen ek RI Ten In RUN IER ERR LT RR 2 10 Table of Contents i Version 1 01 Release Date 05 October 2011 A List of Figures Figure 2 1 Dropper Controller aa 2 1 Figure 2 2 S perspring Controlle ui ein RR RC CR RR 2 4 Figure 2 3 Auto Leveling Portion of System Interface Module sseses 2 6 Figure 2 4 The Tele g and g software Interface iiee eee eee nnn nhanh na nh na nnn nnnm 2 7 Figure 2 5 Rear View Of the SIM iia ihr a ER DG SDN UE o 4D GUT CC CR a x 2 7 Figure 2 6 Rear View of th SIM suada on Hd lH PR RA E RUM ij lk ia 2 7 Figure 2 7 Re
12. pring leveling system not currently implemented interferometer APD power and dropper controller Encoder and Motor are now built into the SIMx unlike previous SIM versions Trigger Connections e DROPPER TRIGGER OUT Digital signal sent when dropper lifts and when dropper drops This should be connected to ARM on the Time Interval Analyzer TIA card in the ex Box This is a duplicate signal of TRIG OUT on the front of the SIMx TRIGGER IN Used to externally trigger the dropper controller COMPUTER TRIGGER OUT Used to externally trigger a second Dropper Controller when debugging additional gravity meter systems System Interface Module 2 9 Version 1 01 Release Date 05 October 2011 A ML 1 Laser Mode and Lock Mode The laser mode and lock are for communication with an optional ML 1 HeNe laser See the ML 1 Polarization Stabilized Laser Operator s Manual for details Analog Fringes In A BNC from ANALOG FRINGES on the interferometer base IB should be connected here This fringe signal is used on the front of the SIMx for alignment set up purposes and the signal is used to provide test mass position information to the Dropper Controller circuit USB Connection A type B USB cable connects the SIMx to the system controller laptop This signal is used to send analog sensor information laser 1f values barometer ion pump current etc to g software and it also communicates digital trigger informat
13. r ratio for fine control The main servo electronics control the coil magnet forcer moves the main spring support in such a way to keep the position of the reference mass constant relative to the detector This active servo effectively weakens the main spring synthesizing a long period isolation device The active period of the Superspring is nominally about 60 seconds Operation Using the SIMx ZERO SERVO ZERO is used to automatically position the Superspring corner cube in the center of the detector range With the Superspring travel lock disengaged monitor the SPHERE position using a DC coupled voltmeter Once the voltage has settled down to a few 10s of mV enable ZERO The spring should come to within approximately 50 mV of zero SERVO is used to enable the servo circuit on the Superspring The two functions are mutually exclusive one cannot zero the spring while the servo is enabled and vice versa Once the spring has settle down near the zero position enable SERVO This activates the feedback system isolating the reference mass from ground noise Note that the SERVO must be enabled while acquiring gravity data BNC Outputs for Superspring Controller System Level There are two BNC outputs in the Superspring controller SPHERE is a voltage proportional to the location of the Superspring corner cube Ideally this is within 100 mV or so of zero COIL is a voltage proportional to the current being applied to the
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