Maintenance manual - MSU Department of Physics and Astronomy
Contents
1. gt Fo k S 5 5 S oS ee ey we We S m 6 S S 6 SE amp a A A 3 lt 5229287285 SSFES EERE EER SE 2 cis Ste5 E ESRR Computer 1 2 3 3 4 8 Motor Driver 1 1 3 Motor Driver 2 1 3 Motor Driver Assembly 5 Umbilical Box 4 7 6 D Power Supply 1 1 7 Power Supply 2 1 7 Power Supply 3 1 7 Motor Bulkhead 5 Detector Controller 1 6 7 Detector Controller 2 6 7 Vacuum Gauge 1 8 ID Name amp Number Part Number Description 1 Power Cord 7 NA 2 Ethernet Cable 1 100Base TX 3 Motor Control Cable 2 Natlnst SCH68C 4 Data Cable 1 Natlnst 183432A 01 5 Motor Cable 1 NA 6 Umbilical 2 Black Box EFP080 010M MT RJ Multimode Duplex 62 5 um 125 um Fiber Optic Cable 7 Cable on Power Supply 3 CUI DTIMO60200UDC P5 HF 8 Gauge Cable amp PS 1 Inficon 353 511 Table 7 Cabling 33 A 4 Software A INSTRUMENT DESCRIPTION A 4 Software To start the software run homeSpartan SpartanGUI and the window in Figure 14 should appear The software has several components which are described briefly here SOAR Spartan IR Camera MICHIGAN STATE z N K j whe O OO age status Pictstree Y YT Y ERO TT te 000 1193 Bice Bo E forEngineering Put Off L Norebook Show Contexual Help Put Off Line Abort Stop a Figure 14 SpartanGUIl which is the main window of the software For a more complete description see Spartan software manual S2. 115 SIZE DRAWING CHECKED DWG NO S5 A003 SHEET 1 of 1 SCALE None FILE ISC Spec Figure 5 Bolts and pins on the ISB The instrument uses three of the four bolts at the north south east and west positions in the picture 5 2 2 Attaching to the instrument support box ISB Turn the ISB so that the face that is to receive the instrument is up Insert the 8 mm pins into the ISB Figure 5 Lower the instrument onto the ISB Orient the instrument so that the filter access port is accessible Bolt the instrument on with three M10 1 5 bolts You will have to insert shims to align the primary mirror with the Lyot stop This will be done by looking at a bright star that is far out of focus See 5 3 Installing the computer amp electronics Install the computer motor drivers and power supplies in the electronics rack Connect the cabling per Figure 13 andlTable 4 16 5 4 Installing hardware 5 INSTALLATION 5 3 1 Connecting AC power Proper connection of AC power is a mystery that may depend on the radio frequency RF noise and wiring of the locale The following works in the laboratory Use the same AC circuit for the computer and motor driver vacuum gauge and power supply for the detector controllers Connect the vacuum enclosure to safety ground the green wire or round connector on the AC power plug With the following scheme noise does appear in the image Use two different AC circuits for th
3. C V V Black X x 22 A1 4 4 M6 8BN M5Rev P31 Z G G Yelow E E 39 A1 5 MS5Rev wa M5Fwd P31 Y H H Purple F F 40 A1 6 M5Fwd M6Rev P32 Z J J Grey 6 G G 30 A2 5 M6Rev M6Fwd P32 Y K K White 2 H H 29 A2 6 M6fw M7Rev P33 Z L L Green J J 36 A3 5 M7Rev M7Fwd P33 Y M M Orange 3 c 37 A3 6 M7Fwd L M8Rev P34 Z N N Blue 8 P p 27 A4 5 M8Rev E M8Fwd P34 Y U U Brown o n n 28 A4 6 M8Fwd Common P31 34 c T T Red b b 38 A1 4 7 M5 8Com SafetyGnd P31 34 a Shell C Dshield g Shell g 4 A1 4 8 SafetyGnd 12 4 3 Detector electronics 4 TROUBLESHOOTING Power Check the power rails by looking at the indicator light emitting diodes LED Fig ure 3 To enable the indicating LEDs on the controller card you must push the button below the LEDs Regulators make each of the power rails 3 3V and 1 8V on both cards and 5V on the controller from the 6 V power supply If all of the power rails are down swap the 6 V power supply If you cannot read a picture there is a problem in the digital circuits If you can read a picture but the picture does not look right there is a problem in the analog circuits Examine the four quadrants of the picture If one quadrant is bad an analog signal chain the flexible cable or a clock driver for that quadrant is bad If all quadrants are bad the power to the detector or the flexible cable is bad Swap detector controllers to determine whether the problem lies with the detector controller or something inside
4. The detector requires two adjustable voltages vReset and biasGate and the controller requires a DC offset for each quadrant vOffset0 vOffset3 These must be adjusted for each detector To clear the photoelectrons the charge storing capacitor is connected to vReset The potential biasGate affects the speed of the amplifier on the detector The detector controller has digital potentiometers for adjusting the voltages For vRe set the conversion between the setting z and voltage is and for the others the conversion is Vother 5 000 V 1 256 For vReset and biasGate we have found that the manufacturer s setting is fine To set vOffset the signal level for the picture with no light and the signal level for the reference pixel must be low but not off scale near zero The information on the images is in two places In the instrument log the entry MRefShort is the average signal level of the reference pixels the 1025th column of each quadrant for the short image MRefShortDrift is the change in the MRefShort since the last time the digital pots were loaded MShort is the median of the light sensing pixels for the short image MShortDrift is the change in the MShort since the last time the digital pots were loaded MLong is the median of the light sensing pixels for the image long short More detailed information is in StashImageStats vi To open its front panel in the Window menu on SpartanGUI select the item I
5. log that was started on 31 January 2006 is named instLog TP2006 01 31 txt The format of the file is tab separated variables which means Excel can read it The units of pressure is mtorr and the units of temperature is K 2 3 Renewing the getter The vacuum degrades over time because of permeation through the o rings When cold the vacuum must be below 30 u Torr 0 03 umHg 40 x 107 mbar for heat loss by gas conduction to be less than that by radiation The prediction is that the lifetime of the vacuum is well over a year We do not have sufficient time to test that prediction This procedure may be done with the instrument on the telescope 2 4 Changing filters 2 ROUTINE MAINTENANCE The temperature of the charcoal getter must rise above 95 K to release oxygen which is the most abundant gas that permeates through the o rings If the temperature does not rise much higher there is little risk that pixels on the detector become damaged Preparation You must record all work on the vacuum in the Spartan Vacuum Notebook You need an oil free mechanical pump Let the temperature rise to at least 95 K Allow the liquid nitrogen to run out After about a day the temperature should warm to 100 K If a lot of gas is released warming takes less time Attach an oil free mechanical pump to the pumping port Turn on the pump and wait a few minutes for the plumbing to evacuate Open the valve Pump until the pressure is below 10 mTorr Do no
6. old ones Use the computer to move the wheel Verify positioning When all of the filters are in place move the wheels to position 0 Check that the cell 4 on the big filter wheel and cells 9 and 10 on the little filter wheel are visible through the filter access port If those cells are not visible the wheel position is lost and you must reinitialize it See Close the door on the COB and replace the aluminized Kapton thermal reflector Replace the Conflat cover on the filter access port Use a new copper o ring Pump the instrument and cool See See 3 1 and 2 5 Window inspection amp cleaning 2 ROUTINE MAINTENANCE 2 5 Window inspection amp cleaning This section is taken with slight changes in wording from the GNIRS Service and Calibra tion Manual 2 5 1 Inspecting the window The entrance window should always be inspected prior to preparing the instrument for use and after any prolonged use on the telescope Use a bright light to look for dust stains and other contamination as well as cracks or chips Contamination will almost always be on the outside but be aware that it might be on the inside of the window The most common contaminants will be small particles dust hairs etc If the window is chipped or cracked it must be replaced since the fractures will tend to propagate with time and may lead to catastrophic loss of vacuum Do not touch the window surface Use of a facemask is recommended 2 5 2 Cleaning th
7. res collimator The temperature of the arm for the wide field camera mirror has a 9 hr e fold time At t 2da the temperature of the mirror is within 1C of the equilibrium temperature In the legend the sensors are ordered by the temperature at the first point The temperatures of the mask wheel and detector are very close 4 TROUBLESHOOTING 4 Troubleshooting This section describes tests for isolating problems in the mechanisms and in the detector electronics 4 1 Software installation LabView pops up a message Please find the VI named xxx vi LabView cannot find a VI in folders that it searches If you can find the VI respond with the location of the VI If you cannot find it the file tree was not copied correctly Since LabView saves a list of folders that it needs to search you will not have to fix this problem more than once Message Detector controller disconnected appears in the instrument log The NI6533 card is not installed in the computer Message Motor controller s disconnected appears in the instrument log The NI7334 motor controller s are not installed in the computer 4 2 Mechanisms Proper function of the rotation stages requires the motor controller motor driver cabling and indexing switches See Table 7 for a block diagram Each motor controller NI 7334 which is inside the computer controls a motor driver Prismatics MDM2200 and each motor driver can handle 4 mechanisms which are c
8. 1 Open the window of Pressure TemperatureLog in order to look at the temperature sensors and the pressure Set the time step for the log If you want to monitor the pressure open the window of PressureSensor 3 2 Cooling the instrument 3 PUMPING AND COOLING 2 Attach the hose that supplies liquid nitrogen to the fill port Figure 9 Fill until liquid comes out of the vent The filling history Figure 2 shows that filling every 20 min is required initially The pressure rises when nitrogen is exhausted that the fill time lengthens to 12hr after 18 hr About 150 L of liquid nitrogen is required 3 When the temperatures of the wide field camera arm and the wide field camera post are within 2 C the temperature of the optics and cryo optical box have reached equilibrium and the focus is stable S 140 T O l lwrcamarm E D 120 _ 3 100 L Tmw det Q I THeater i 80 TcoB a 60 m 40H 20f P C0 L U 0 5 1 1 5 2 t da Figure 2 Pressure and temperatures of the arm for the wide field camera mirror detector mask wheel heater and cryo optical box COB during cooldown for Run 3 of Cold Test 3 The first filling with liquid nitrogen occurred at t 0 The pressure rises whenever nitrogen is exhausted or when warm gas is introduced at the start of a fill Since the heater was not attached to the COB securely its equilibrium temperature is higher The sensor on the COB is near the high
9. Maintenance amp Operating Manual Spartan IR Camera for the SOAR Telescope Edwin D Loh Department of Physics amp Astronomy Michigan State University East Lansing MI 48824 Loh msu edu 517 884 5612 17 February 2006 15 November 2006 modified 3 December 2007 modified 28 August 2008 added N2 and vacuum interface 15 February 2009 added instruction for programming ERROMs new instructions for setting digital pots Abstract This manual describes the installation maintenance and operation of the Spar tan Infrared Camera It is intended for technicians who work on the camera It is not intended for astronomers 1 Safety of the instrument and personnel 1 1 Instrument as a bomb keep the poppet free When the instrument warms the cryogenic charcoal getter may release a large quantity of gas which vents through a poppet valve Figure 9 if the internal pressure becomes high Without the poppet the instrument may become a bomb 1 2 Don t open the instrument when cold When venting the instrument to air the instrument must be at ambient temperature Vent ing when the temperature of the instrument is below the dew point will cause condensa tion and damage the rotation stages 1 3 Recovery from lost vacuum 1 SAFETY 1 3 Recovery from lost vacuum lf vacuum is lost when the instrument is cold the following procedure will prevent damage to the rotation stages You must pump so that ice sublimates and does not liquefy Liqu
10. alled axes See Table 2 for the assignment of the axes The cabling for the motors in in Table 3 This section describes ways to isolate problems The motor drivers Prismatics MDM2200 have one fuse next to the power cord and several fuses Table 2 Assignment of controller amp on the inside axis for each mechanism Three diagnostics forMechanismEngineer in Mechanism Cont Axis the VI SpartanGUI the VI MechanismHoming and Big Filter Wheel the VI MechanismMoving are helpful if the mech Little Filter Wheel anism is working partially They show the inferred 1 21 Collimator motion of the mechanism they do not show the ac f 12Cam tual motion since the only feedback from the mech Mask Wheel 2 3 anism is the limit switches Keep this in mind when you read the graphs of the motion If the motion causes a limit switch to engage then the mechanism is truly moving If the 1 1 1 2 1 3 1 4 4 2 Mechanisms 4 TROUBLESHOOTING motion does not produce a change in the state of a limit switch then there is no guarantee that the mechanism actually moved The Spartan software shows the state of the limit switches at initialization and updates when a mechanism is moved If you suspect a limit switch changed state you may initialize the mechanisms to see the state of the switches If you want to monitor a limit switch continuously use NI Measurement and Automation Explorer NI MAX If the mechanism position is incorrect either the mechanism is n
11. ay add comments that will help diagnose problems Help CameraControl controls the detector It sends commands to the detector controller cards and receives status and images from them Mechanismlnitiation initializes the mechanisms by initializing the motor controllers and reading the locations of each mechanism from files on the disk MechanismHoming locates the reverse limit of a mechanism in order to test or set its home position MechanismMoving moves the mechanisms PGauge reads the Inficon pressure gauge LogTfempPressure maintains a log of the temperatures at several points in the instru ment and the pressure inside the instrument 35 A 4 Software A INSTRUMENT DESCRIPTION Telescope Link communicates with the observatory control system OPEX SpartanServer receives commands from OPEX and passes them on to StartanGUI In addition it send status to OPEX TUI Link communicates with the text based user interface StartanTUI is a text based user interface It may run on a remote computer In order to reduce clutter most of the VIs run without a visible window To make a VI visible use the Window menu of SpartanGUI A 4 1 Volatile data Volatile data are the mechanism positions and the current image ID The data are stored in these files whose path is in the entry volatileDataPath in the configuration file spartan txt mech0O txt mech5 txt Before moving mechanism 0 the flag moving is written to the file mechO
12. ble panel Bulkhead Motor PCB amp cable panel amp vacuum bulkhead amp motor PCB amp motors x l i 2 2 5 5 o e o amp 8 e 2 oc am S 5 EZ 3 53 Ee ee i e lt s 6 865 36 eo lee 2 lig Y Z lt lt F Cont 2 Q18 P18 Wire P20 Q20 P22 M1AP P A A Yellow K K 6 B1 1 Heater M1BP P B B Purple lt L L Fa B1 3 M2AP P13 C C Grey o M M 9 B2 1 M2BP P13 4 D D White amp N N 11 B2 3 M3AP P37 A E E Green 5 P P 2 B3 1 M3AP M3BP P37 B F F Orange 5 1 B3 3 M8BP M4AP P S S Blue t t 3 B4 1 M4BP P154 R R Brown O d d 5 B4 3 e AN P37 T P P Red e e 8 B3 2 M3AN BN P37 C V V Black q q 10 B3 4 M3BN M1Rev P8 2 G G Yelow R R 34 B1 5 Heater M1Fwd Pg H H Purple S S 35 B1 6 2 M2Rev P9 3 J J Grey S T T 25 B2 5 M2Fwd P9 K K White U U 26 B2 6 M3Rev P37 Z L L Green j j 31 B3 5 M3Rev M3Fwd P37 Y M M Orange 5 s s 32 B3 6 M3Fwd M4Rev P N N Blue amp r r 23 B4 5 M4Fwd P U U Brown of h h 24 B4 6 Common P37 c T T Red 33 B3 7 M38Com SafetyGnd P37 a Shell A Bshield a Shell la 20 B3 8 SafetyGnd Cont 1 Q19 P19 M5AP P31 A A A Yellow A A 16 A1 1 M5AP M5BP P31 B B B Purple O B B 17 A1 3 M5BP M6AP P32 A C C Grey Z C C 19 A2 1 M6AP O M6BP P32 B D D White 6 D D 21 A2 3 M6BP M7AP P33 A E E Green s Z Z 12 A3 1 M7AP E M7BP P33 B F F Orange S m m 13 A3 3 M7BP M8AP P34 A S S Blue i k k 14 A4 1 M8AP M8BP P34 B R R Brown O W W 15 A4 3 M8BP 2 AN P31 34 T P P Red S Y 18 A1 4 2 M6 8AN BN P31 34
13. blems Heartbeat On the Spartan GUI the light Heart blinks about once a second to indicate that the detector controller is communicating with the computer The light changes state each time the detector controller sends status to the computer which occurs at 2 5 Hz If the light changes state once every 5 s then the computer is not receiv ing status If the light blinks at 1 25 Hz the umbilical umbilical card data cable the data card in the computer two power supplies and the digital section of the detector controller are all fine Umbilical Board amp NI 6533 Data Card On the CameraControl GUI press the button send command which tests only the communication between the umbilical card and the computer If that fails communication is lost Check that the umbilical cable is seated Check that power to the card is OK by swapping power supplies If the cable and power are OK then the umbilical board or the NI 6533 data card inside the computer is not functioning Detector Controller If the temperatures are OK Use the CameraConitrol GUI most of the detector controller is functioning since reading the temperature requires digital and analog parts to function Proceed to check power rails if reading temperature fails 11 4 3 Detector electronics 4 TROUBLESHOOTING Table 3 Motor and heater wiring M3 mask wheel M5 big filter wheel M6 little filter wheel M7 f 21 collimator M7 f 12 camera Motor driver Ca
14. container removed 25 7 ACKNOWLEDGEMENT 7 Acknowledgement We thank the Center for Cosmic Evolution Michigan State University the SOAR Tele scope the National Council for Scientific and Technological Development of Brazil CNPq State of Sao Paulo Research Foundation FAPESP and the National Science Founda nior for funding this camera We thank Brooke Gregory for his many suggestions to clarify this document This material is based upon work supported by the National Science Foundation under Grant No 0242794 Any opinions findings and conclusions or recommendations expressed in this material are those of the author s and do not necessarily reflect the views of the National Science Foundation 26 A INSTRUMENT DESCRIPTION A Instrument description The Spartan Infrared Camera operates in the 1 2 4 yu spectral band It has two focal ra tios wide field with 68 mas pixel for a wide field and high res with 41 mas pixel for high angular res olution In the high res configu ration the detectors resolve the diffraction limit The detectors are HAWAII 2 arrays HgCdTe Astronomical Wide Area Infrared Imagers with 2048x2048 pixels The instrument is cooled with liq uid nitrogen The symmetrical design min imizes flexure The optics and cryostat for nitrogen bolt on the top and bottom plates of the cryo optical box COB Figure 11 As the Nasmyth port turns to compensate for the ro tation of the field the in
15. cus image of a star The telescope is adjusted to put a stellar im age out of focus using the telescope sec ondary on the Spartan detector If the fo Figure 7 Flamant transition and orange shim cal plane of the telescope is shifted defocussed by an amount z the diameter of the stellar image on the detector will be D z16 f where f is the focal ratio at the image For z 2mm with the f 12 channel D 2 7 mm 150 pixels The edges of the out of focus image should be determined in pixels in the x and y directions respectively 4 numbers A precision of 2 2 pixels is required xxx This will not likely work since moving the secondary probably moves the image 1 Install the tight Lyot stop for the wide field channel Point at a bright star Move the telescope focus 2 mm from the true focus Find the edges of the image 2 Install the loose Lyot stop for the wide field channel Find the edges of the image The image should be slightly larger 3 If the two images are concentric to R lt 0 015 then the alignment is finished 4 If not change the shim For the direction with two bolts add to one side and remove from the other side an amount R R f olI dpolt 8 R mm For the wide field channel R 20 and foo 750 dait 300 For the direction with a single bolt add or remove 86 R mm from the single shim Then repeat 21 5 8 Setting detector parameters 5 INSTALLATION 5 8 Setting detector parameters
16. down and the top toward the viewer 29 A 1 Optics A INSTRUMENT DESCRIPTION Back m Camera side Baffle Right Collimator side Baffle A strut E f y Bathtub Attachment to ISB Figure 11 Cryo optical box inside the bathtub of the vacuum enclosure 30 A 2 Vacuum amp cooling A INSTRUMENT DESCRIPTION A 2 Vacuum amp cooling The vacuum enclosure consists of a bathtub and lid Poppet Valve Pumping Port which mate at a flange visible in Figure 9 amp Figure 11 The vacuum plumbing Figure 12 has a pumping port which is Conflat with a quik connect adapter The poppet valve is a safety relief It opens if the internal pressure becomes high as would be the case if the charcoal getter warms and releases the nitrogen and oxygen adsorbed from a large leak The vacuum gauge is an Inficon BP400 Bayara Alpert Pirani According to the manual The gauge functions with a Bayard Alpert hot cathode ioniza tion measurement system for P lt 2 0 x 1072 mbar and a Pirani measurement system for P gt 5 5 x 1077 mbar In the overlapping pressure range a mixed signal of the two measurement systems is N2 Fill output The hot cathode is switched on by the Pirani N2 Purge for Window measurement system only below the switching thresh old of 2 4 x 1072 mbar to prevent filament burn out It is switched off when the pressure exceeds 3 2 x 107 mbar The actual pressure P and pressure reading Pr are related b
17. e power supply for the detector controllers and the computer and motor driver We have found that the safety grounds of two AC circuits in the lab have a large RF noise between them The detector wires may pick up radiation from the motor wires even though the de tector circuit board is inside the aluminum vacuum enclosure a Faraday cage and the flexible cable to the detector controller is a microstrip traces over ground plane 0 025 mm away The bandwidth is in the MHz range and the impedance of the video line is in the KQ range The most likely path for radiation is from the motor wires to the detector circuit board since the detector circuit board and detector have the largest antenna areas Wires that originate in the computer and motor drivers go inside the Faraday cage of the vacuum enclosure If the ground of the computer and motor drivers are different from the ground of the detector controller then the motor wires may have tens of volts of RF noise We have found that using a single AC circuit and connecting the safety ground of the AC power to the vacuum enclosure is sufficient to reduce the RF noise to a level that is barely detectable in the Fourier transform of a dark image 5 4 Installing hardware You must have already installed LabView The software uses LabView version 7 1 and the components Traditional NI DAQ NI Motion and NI VISA If you are uncertain whether the components are installed open NI Measurement and Automati
18. e sent to the server for execution XXX is the name of the computer This is an example 37 A 4 Software A INSTRUMENT DESCRIPTION Spartan IP_Server 35 10 222 145 IP_Client 35 9 2 14 IP_Port 30040 AOS IP_Server 139 229 3 100 IP_Client 139 229 3 217 IP_Port 5679 TUI Link must run on the same computer as SpartanGUI StartanTUI may be ona remote computer The server enforces security using the IP address of the client The IP address of the client must be in the configuration file when the server starts otherwise the server will not open a communications link with the client 38 A 4 Software A INSTRUMENT DESCRIPTION fos i 0617 02060 097 Figure 15 Vis defaultOptic top left mechanismParameter top right and SpartanToWheel Names bottom for configuring the instrument 39 B OTHER DOCUMENTATION B Other Documentation Spartan documentation Loh E 2007 Loh E 2006 Loh E 2006 Vendor documentation e inficon pressure gauge Inficon 2002 Operating Manual BPG400 Bayard Alpert Pirani Gauge www inficon com e NI digital input output card National Instruments 2001 653X User Manual www ni com e INI motor controller National Instruments 2001 7344 7334 Hardware User Man ual www ni com Prismatics 2005 MDM2200 Reference amp Maintenance Manual www prismatics com 40
19. e the lifting jig or rotating jig to move or rotate the cryo optical box Use a hoist attached to the lifting bars Figure 9 to move the instrument 2 ROUTINE MAINTENANCE 2 Routine maintenance See Table 1 for the schedule for routine main tenance Although most tasks are indeed rou Table 1 Maintenance schedule tine changing filters takes at least a week be Task Trigger cause of the time to warm up and cool back Add liquid nitrogen Daily down Check pressure Monthly Renew vacuum P gt 30 plorr Change filters When needed 2 1 Adding liquid nitrogen Add liquid nitrogen at least once every 18 hours A few pixels fail every time the detectors warms to room temperature You have 18 hours after nitrogen is exhausted before the detector warms by 20 C which is still safe The fill port is 1 2 in VCR face seal with a metal gasket The parts are a Swagelok male nut SS 8 VCR 4 a socket weld gland SS 8 VCR 3 and a copper gasket retainer assembly CU 8 VCR 2 GR An adaptor converts VCR to JIC Swivel also called 1 2 in flare nut which is common for liquid nitrogen plumbing To fill attach the line from the nitrogen dewar to the fill port Either port may be used as the fill port Fill until liquid comes out of the vent port The capacity of the nitrogen container is 7 L 2 2 Checking the pressure log Check the log of pressure instLog TPyyyy mm dd txt to estimate the duration be fore the vacuum must be renewed For example the
20. e window The procedure to be followed depends on the level of contamination If only loose parti cles are present follow step 1 which may be carried out with the window still mounted in the instrument Otherwise proceed to step 2 1 Mild Cleaning for Light Contamination dust lint particles Use an air bulb to blow off any loose contamination from the surface of the optic before proceeding to the cleaning steps If this step does not remove the contamination continue to Step 2 Do not use shop air lines because they usually contain significant amounts of oil and water which will contaminate the optical surface Air lines with filtering suitable for optics cleaning can be used Do not use of portable compressed cleaners such as Effadusters The propellant evaporates quickly and can produce a localized region of very cold air which can crack the entrance window 2 Mild Cleaning for Light Contamination smudges fingerprints It is strongly recom mended that this procedure be carried out with the window removed from the in strument If it is not possible to do this localized cleaning with the window installed may be successful if carried out with caution a Saturate an unused cotton swab or a cotton ball with methanol or propanol Gently wipe the surface with the saturated cotton Do not rub hard Use only the weight of the saturated cotton ball 6 3 PUMPING AND COOLING b Drag the cotton across the surface just fast en
21. efault SCH2 29 May 2007 Default gain is 5 Temperature data changed from 10 to 11 bits Umbilical controller UG4 17 Jul 2006 Table 6 EPROM versions 23 6 SHIPPING 6 Shipping This section describes the procedure for removing the instrument from the shipping con tainer The container is designed to protect the instrument for a 30 cm drop and to insu late it from vibration With the sides of the shipping container removed and rollers installed the container becomes a fixture for transporting the instrument inside the observatory See Figure 8 6 1 Unpacking 1 Remove the top and side panels which are held by screws 2 Remove the boxes which contain ancillary equipment and fixtures 3 Remove the top plate which has the horizontal safety bumpers 4 Remove the parts that are screwed onto the base of the shipping container or the top plate 5 Install the wheels if you want to move the instrument 6 2 Removing the instrument from the fixture You will need a hoist 1 Remove the three bolts that hold the instrument on the base 2 Attach straps to the lifting rods Lift the instrument 3Loh M Loh O amp Loh E 2006 Test of the Shipping Container Spartan IR Camera for the SOAR Telescope 24 6 2 Removing the instrument from the fixture 6 SHIPPING Figure 8 Top left instrument leaving the lab Top right side and top removed Bottom Instrument packed with the sides and top of the shipping
22. flexible cables that connect the cold detector and warm electronics have very low cross section and therefore low conduction The motor wires run on a board with thin traces which reduce conduction Because the window radiates into about 0 9 steradian of cold it may cool below the dew point on very humid days Some nitrogen boil off after warmed in a length of pipe blows on the window to purge the surrounding air of water A 3 Electronics and cabling The electronics are in several places The block diagram and cables are in Figure 13 and Table 7 e Inside the vacuum are detector printed circuit boards PCB and a motor PCB The motor PCB is a thermal insulator and a fan out e On the instrument outside the vacuum is an electronics box which contains the detector controller PCBs e Inthe cooled electronics rack up to 7 m from the instrument are two motor drivers INI MID 7604 the umbilical PCB and the computer e Inside the computer are two motor controllers NI PCI 7344 and a data card PCI DIO 32HS for communicating with the umbilical card 32 A 3 Electronics and cabling A INSTRUMENT DESCRIPTION In Vacuum Rotation Stages Detector PCBs Motor Cables Motor PCB a Vacuum Gauge a jua Motor Controllers Power Supply Umbilical PCB Data Card Figure 13 Cabling schematic Detector Cables Motor Cable O Gauge Cable
23. ges imagePath E images volatileDataPath C data volatileDataPath C data observingLogPath C obsLog observingLogPath C obsLog instrumentLogPath C instLog instrumentLogPath C instLog 35 10 222 84 computerName horolog4 imagePath C images volatileDataPath C home Spartan data observingLogPath C home Spartan ObsLog instrumentLogPath C home Spartan InstLog compensate for backlash the offset from the index to the 0 th position whether the mechanism is a wheel and therefore the last position is adjacent to the first and the serial number of the rotation stage You must access the block diagram to make changes filterBalance xls is a spreadsheet for figuring out where to put filters to balance the wheels SpartanToWheelNames vi Figure 15 contains the correspondence between the mech anism positions and names of the optics detectorSetPoint vi contains information about the detectors namely the serial number location and operating voltages initDatabase vi contains information on the observatory time system equinox and ver sions of the hardware and software hdr obs txt contains the FITS key words that are implemented soar_commsXXxX txt contains IP addresses of TUI Link the text based server Spartan TUI the text based client and Telescope Link the server that provides information about the state of the telescope The observer types commands on the client which ar
24. ght onto the detector A plano convex lens near each detector flattens the field The mirrors are off axis to avoid blocking the beam There are two focal ratios To switch between the two focal ratios rotation stages move the high res collimator and the wide field focusing mirror move in or out of the beam Two fold mirrors make the system more compact Two filter wheels allow a large number of filters The little filter wheel is at the image of the primary mirror of the telescope For the K band where the Lyot stop must be accurate to block thermal radiation the Lyot stop must be in the little wheel and filters must be in the big wheel For other bands the filters may be placed on the little filter wheel A mask wheel at the telescope focus holds the field stops and masks for coronagraphy or slits for spectroscopy 28 A 1 Optics A INSTRUMENT DESCRIPTION 10 f 21 Focus g Miror ep 1 5 f12 Collimating 5 f21 Collimatinar Bi inserted orren 10 f 12 Focusing Mirror insertedsor removed i A 13 Detector 1of4 12 Field flat ening Lens 1 of 4 11 Pyramidal Mirror jee 4 N2 Cryostat p 3 Mask Wheel Da hoa Fold Mirror 2 at telescope focus WE 8 Bittle Filter Wheel 2 Thermal Reflector 5 at pupil 1 Entrance Window Fold Mim 7 Big Filter Wheel 6 Fold Mirror 1 Figure 10 Optical schematic oriented with the front of the instrument
25. heel must be balanced so that the gravitational torque is less than 0 07 N m The little filter wheel holds Lyot stops which must be placed accurately and the anti backlash spring cannot resist larger torques The balance of the big filter wheel is not as Critical since the filters are oversized However it must be approximately balanced to reduce the load on the rotation stage The torque for one cell with a 3 mm thick silica filter is 0 10 N m on the big filter wheel and 0 07 N m on the little filter wheel Enter the filter masses and locations in the spread sheet homeSpartan Configuration filterBalance x1s to check the balance Modify the VI homeSpartan Configuration SpartanToWheelNames vi which allows the software to know the locations of the filters After you restart the software the new locations will be in effect Besides the filter you will also need 1 the spring for retaining the filter 2 the filter insertion tool and 3 a 6 in copper Conflat o ring 2 4 2 Procedure for changing filters Try to minimize the time when the instrument is open Water condenses on the internal surfaces and pumping the water out takes a long time Cover the filter port when you are not actually accessing the filters Warm up the instrument See Warming up the instrument in the Assembly Manual Remove the Conflat cover on the filter access port and open the door on the cryo optical box COB Insert the new filters and remove the
26. id water will damage the lubricant on the rotation stages Close the leak You have time If the instrument is at 77 K it will take days to warm up Attach a dry oil free pump to the pumping port Turn on the pump After a minute open the valve Pump until the instrument is a few degrees above ambient You may want to turn on the heater to speed this up See the section Warming up the instrument in the Assembly Manual 1 4 Fill liquid nitrogen in an open area Cooling the instrument from ambient must be done in an open area to avoid asphyxiation since the nitrogen displaces the air in a large 8mx8m room Operating in a closed laboratory is acceptable since the nitrogen in the cryostat if it were to escape suddenly would merely fill a 8m x 1m closet 1 5 Electrical ground yourself A detector can be damaged with electrical discharge from the body The parts that have a direct connection with the detector are the detector card the controller card and the flex ible cable When working with these use a wrist strap that is connected to ground There is a copper wire on the instrument near the detector controller for grounding yourself 1 6 Cleanliness Keep oil from getting inside the vacuum enclosure Use an oil free pump Wear gloves when handing the parts that go inside the instrument Keep dust from getting in the instrument Work in a clean room 1 7 Save your back use a hoist The instrument is heavy Us
27. ilt Shim 0 5 mrad at shim 0 15mm 192 rotation No pinned x amp y translation No pinned z translation Shim 3mm 5 7 Alignment 5 INSTALLATION PCI DIO 32H5 Device 1 Measurement amp Automation Explorer Sele File Edit View Tools Help Configuration 2 M My System H Data Neighborhood 2 a Devices and Interfaces a Traditional NI DAQ Devices eee PCI DIO 32HS Device 1 PX Pal System Unidentified x H F Forts Serial Parallel ce IVT Instruments H 9 Scales Software H 6 Remote Systems iili PST Properties FalDelete HA Test Panels yz Shou Help Device Number 1 The NI DAQ device number FH serial Number DxBDC8AD The serial number of the device Attributes Trajectory Settings Measurement amp Automation Explorer 46 ID x File Edit View Tools Help Configuration 2 EJ Initialize w Change Settings g Apply Refresh 12 Defaults st Show Help El LS My System x E Data Neighborhood le Devices and Interfaces 2 E al PCI 7334 1 Device Resources a Default 7330 Settings 1 E l Axis Configuration H A Axis E l narra Setting E A Digital IO Settings H A ADC Settings c Encoder Settings 6 JEA PWM Settings oo Synchronization Setting i 0 689 Interactive i PCI 2334 2 a Scales HA Software Remote Systems IT rajectory Settings Type of Settings Trajectory Settings Description Configures trajectory parameters for the axi
28. mage Statistics Nominally the signal level changes 1536 ADU for a change of 1 in vOffset with the gain of the signal chain set to 3 Since the steps of the Analog Devices AD8400 digital pot are accurate to 1 4 step expect wide variations This is the procedure 1 In SpartanGUI press the buttom forEngineering Select the Setup tab The offsets vReset and biasGate seitings are on this tab 2 Adjust vOffset so that the intensity of the light sensing pixels at low light level and the intensity of the reference pixel are both at least 5000 counts 22 5 9 Programming EPROMs 5 INSTALLATION 5 9 Programming EPROMs The detector controller and umbilical card each use one Atmel AT17LV010 10Jl EPROM 20 pin PLCC package 1 Mbit size The programmer is Atmel s ATDH2200 FPGA Serial Configuration EEPROM Pro gramming Board which connects to a parallel port The software is Atmel CPS Version 8 02 The input to the programmer is a file with an extension mcs sch mcs for the de tector controller and ug mcs for the umbilical board The command is to convert a Xilinx file program and verify These are the programming parameters Option AT6K Other Device AT17LV010 A Reset polarity low Com port LPT1 Data rate medium A2 bit level low Version Date Change Detector controller SCH4 23 Oct 2008 Flush charge while idle Turn off indicator light after 24s SCH3 26 June 2008 Default gain is 3 Ramp and test pods are now disabled by d
29. o ZORA uuo2 1 9Gq ZRI O 1 9 odjuoS 10109160 5 10 O uuo2 ZZ ODdVH sew WEJIOYDIIMS py sn WwoOIsSnNd ZAel sig oduoo 10109190 Z ARI Inoue I AOd YJ LJ Ajddns ISAOd UO Z l noupj JOMOd Z Aes Ajddns samod A 9 zg Ajddns samod uO AR J9 JO1JUOD TROIOU L Aes Ajddns 1 mod A 9 44 odo yeqi4 zZz e c 19 01 U09 1010916 L A amp L gyod piso eagwuN G odo yeqi4 zZz e 2 1 01 U09 1010916 L A amp L z mod pieoyeoiquq Eq odo j9qiq zZz e odjuo9 1010916 L Al yod peo eo1 jiquin za odo yeqi4 zZz e 0 191 01 U09 1010916 L A amp L Quod p9 eo1 iquin IG Q 89 899HS IN A61 peo eoq 4ajndwop PILI OI cG9 IN O s6njd QLLESIN uld I uo pue ud 6L OM YIM 91097 WOIsnND A 9 921d9991 10 0W L AeL s jpe d uolol Z g O I uolloNW S 89O 89HS IN I AedL JOAUP JOJO J lnduuoo Z J9 04JU0D JOJO ZV O I UOO S 89O 89HS IN AedL JOALP JOJO J lnduoo 4 01 U09 JOJOWY IV a1ge9 207 snuluu18 207 snuiwu j aged 18 5 5 Installing software 5 INSTALLATION Configure the NI 7334 motion controller Start NI MAX Configure the Trajectory Set ting according to Figure 6 You must do this for both motion controllers the settings are the same for both Since the software overrides settings in the panels Axis Configuration Axis Setting Trajectory Settings gt Move Complete Criteria and Find Reference you need not do anything with these panels The other panels Digital I O Settings ADC Set
30. on Explorer NI MAX and look at the Software tab Install two NI 7334 motion controllers and one NI 6533 data acquisition card in the computer Configure the NI 6533 data acquisition card to use device 1 You will use the NI Measurement and Automation Explorer NI MAX See Figure 6 Right click on the device to access properties Change the device number to 1 This needs to be done only once since the configuration is saved To start NI MAX go to Start gt All Programs gt National Instruments gt Measurement and Automation 17 5 INSTALLATION Installing hardware 5 4 JQMOd aui A 0 L Olu jqe uooljuj By pue s i ddns 1 mod A 9 y Dna qed MOeU a u d 0 34 SI S1 pue ajqeo UId 02 MOJJeU B JO SOURIS N 91087 u d 08 pIA JO SpUeIS M S pue Bni d y uo JAapJO Ul EN EM N ZM LN LA p j qej 9 9 sio1l099uuo2 10109190 y uo s qe2 qix JjJ SU 01 WANDA y UO SI SPA U02907 qnluleq y JO pis 1440 y UO SI Z OBA uolle5oo7 qnluleq wnnoea y JO pis uo uo Jopesy u Boulu ioloui y UO SI DLA uoleoo1 Bulges qe 1 pu X ZEZSH YUM aged UOOIUI SPA JOSUSS INSS Jd u lnduioo uod ZEZSH_ H ZN 9 ZM 98SN wolsnDg Zoe Z uuo2 aq zeil G H 9jodjuoS 10109160 ZD INS LM asn ui o snO Z ORA Z uuo2 19 ZAel Z 9 jodjuoS 10109160 ZD ZN 9 ZM 9SN uio snO ZNA uuo2 1 9Gq Z I JOIJOUJUOD olo3 q L9 STL 9 LN LM asn won
31. ort left panel of Figure 4 is QF40 The end part in the figure is a 2 3 4 ConFlat to QF40 adapter Lesker FO275XQF40 The QF end is exposed The nitrogen fill and vent ports which are identical use Cajon 1 2 VCR metal gasket face seal fittings center panel of Figure 4 The end part is made of a socket weld gland Lesker 8FVCR GL and a male nut Lesker 8FVCR N A gasket retainer assembly Losker 8XVCR GACR and copper gasket Lesker 8X VCR GAC are needed A VCR to 1 2 Swagelok adapter is provided right panel of Figure 4 The end part is a Swagelok nut and ferrules taken from a female connector for 1 2 NPT and 1 2 tube Swagelok SS 810 7 8 However the Swagelok nut and ferrules on the adapter can attach to any 1 2 Swagelok part 5 2 Installation on the telescope 5 2 1 Lifting the instrument Use acrane Loop lifting straps on the lifting bar Figure 9 Insert the straps on the hook of the crane 15 5 3 Installing the computer amp electronics 5 INSTALLATION REVISIONS DESCRIPTION APPROVED 8 mm diam x 12 dp typ places x180 align pin press fit MXL Thru Typ 12 on 600 BED Thru hole per Schedule NI K Igo Tru R by Imm deep M10515 Thru Typ 4 Thru Hole Schedule N SOAR Project Office National Optical Astronomy Observatories Radius mm 950 N Cherry Avenue Tucson AZ 85726 6732 1 Straight Port 165 E Nasmyth Instrument 2 Bent X 115 SOAR Interface 3 Bent X
32. ot working or the position is lost When the software moves the motors you do not hear a soft whine The motors are not moving Either the motor drivers are not turned on they are not enabled or the motor cable is disconnected When the software moves the motors you hear a grinding noise One of the two phases of the motor is broken If this occurs for only one motor the wire for it is broken If this occurs for all of the motors on a drive then the common wire for the phase is broken Does the mechanism find home Press the button test home on the panel forMechanismEngineer to test the location of the reverse limit switch If the position repeats then the mech anism is fine Press the button store home to save the new home position Does the mechanism make a grinding noise If the mechanism is jammed or one of the two motor phases is disconnected then moving the motor causes a grinding noise Motor Controller amp Motor Driver Each motor controller handles one motor driver and each motor driver handles 4 motors Table 2 If not all of the motors on a controller and driver are failing then the controller is working If one motor is failing swap the plug on the back of the motor driver to decide whether the problem is in the motor driver If the problem is in the motor driver check the fuses inside the motor driver Cabling 1 There are two identical cables between the motor controller and the motor driver Swap the two cables to
33. ough so that the liquid evapo rates right behind the cotton This should leave no streaks If this step does not remove the contamination stop and seek advice from a professional opti cian 3 Pumping and cooling 3 1 Evacuating the instrument You must record all work on the vacuum in the Spartan Vacuum Notebook Use this procedure if the instrument has been opened for a long time in which case water will have adsorbed on the surfaces 1 Preparation You will need an oil free mechanical pump 2 Turn on the pump and keep the instrument value closed to evacuate the hose 3 Open the value a small amount and pump for a few minutes to evacuate the interior of the multi layer insulating MLI blanket If you open the value completely the rush of air may break the taping on the blanket 4 Open the valve completely and pump the instrument for an hour The pressure reached 200 mTorr when the instrument was first assembled When the instrument was Clean fairly free of water the pressure reached 50 mTorr 5 If the pressure is high after an hour pump overnight 3 2 Cooling the instrument Cooling the instrument from ambient must be done in an open area to avoid as phyxiation since the nitrogen displaces the air in a large 6m x 6m room Note that after the cryostat is first filled with liquid nitrogen the instrument continues to cool The parts that are on the rotation stages take 43hr to cool to within 2C of the equilibrium
34. partanGUI is the user s control panel In normal operation the observer need only look at this window Status information is in the top section The observing functions 34 A 4 Software A INSTRUMENT DESCRIPTION are in the observing panel The notebook maintains a record of the observations the observer can log comments in the notebook SpartanGUI has several panels Observing is for the observer The observer presses buttons on SpartanGUI to set exposure time take pictures change filters switch between wide field and high res modes Setup is to setup the detector and the mechanisms The operations are 1 choose the detectors 2 load the operating voltages for each detector 3 initialize the mechanisms 4 test the home positions of the mechanisms and 5 find and store new home positions The parameters that are unlikely to need changing are in a tab control the two tabs of which are named Detector and Plugin Select the button Simulatelnstrument to run without any hardware forMechanismEngineer is for monitoring the mechanisms and more detailed con trol of the them Normally the mechanisms move by the amount needed to change the optics an example of which is the 20 to move between filters This panel allows movement by steps of 0 002 Glossary contains definitions of terms an optical schematic and a map of the detector layout InstLog maintains a record of mechanism movement and unexpected problems The observer m
35. s Move Settings Operation Mode Absolute Position j Stop Mode Decelerate 9 Trajectory Units steps 9 Blending Tare Blend before decelerating 9 Blending Delay m Velocity 2600 lt 4 steps s SA 22767 steps Acceleration aoon map a 0 I ee z Position z Deceleration 4000 steps s 2 Modulus steps Advanced Move Settings Velocity u Base Threshold anon steps Velocity S steps s Velocity fo o of loaded Accel T Override 100 velocity Factor Move Complete Criteria Figure 6 The panels in NI Measurement and Automation Explorer NI MAX for setting up the NI 6533 data acquisition card top and the NI7334 motion controller bottom 20 5 7 Alignment 5 INSTALLATION the tolerance is tight are the x tilt and y tilt of the mounting surface Tilt moves the Image of the primary mirror on the Lyot stop Shims on the Flamant transitions allow adjustment of the these two degrees as well as focus The tolerance for focus is loose focus must be within the focus range of the telescope Two pins fix the other three degrees of freedom The goal is to center the image of the telescope primary mirror on the Lyot stop so that the loss in the amount of light is less than 1 If the pupil is shifted by then the loss is 2R 7tR where R is the radius of the pupil Therefore the requirement at the Lyot stop is d R lt 0 017 2 The pupil can be visualized by looking at an out of fo
36. strument turns along an axis perpendicular to those plates Since the optics are midway between the top and bottom plates and gravity is paral lel to these plates flexure cannot move the image toward or away from these plates Figure 9 Spartan Camera The bathtub lower part and the vacuum lid upper part bolt together at the flange The inside of the instrument attaches mechanically electrically and plumbingly to the bathtub only the lid lifts off freely The connections to the inside of the instrument are all with the bathtub of the vacuum enclosure Figure 9 The vacuum lid mates to the bathtub at a flange to complete the vacuum enclosure The COB attaches to the bathtub through four A struts Figure 11 which are made of G 10 fiberglass a stiff insulating material The electrical connections and nitrogen plumbing also attach to the bathtub Therefore the vacuum lid lifts off freely during disassembly The instrument attaches to the instrument selection box ISB on the telescope through 27 A 1 Optics A INSTRUMENT DESCRIPTION three Flamant transitions The Flamant transition is a semicircular plate that allows move ment to compensate for the difference in thermal expansion of the aluminum instrument and steel ISB A 1 Optics The optics image the curved focal surface of the telescope onto the detector A colli mating mirror collimates the light and images the primary onto a stop A focusing mirror focuses the li
37. t leave the valve open any longer since the getter will then be cleaning the pump and plumbing Fill instrument with liquid nitrogen Check that the pressure is below 30 Torr If the pressure is still high after renewing the getter there may be a leak or the predominant species are hydrogen helium or neon gases that the charcoal getter does not pump effectively and somehow the mechanical pump did not remove these gases 2 4 Changing filters Changing filters should be done very infrequently since it requires warming the instrument and break ing vacuum A few pixels are lost each time the detector is cooled and warmed Furthermore the procedure takes a week 2 4 1 Preparation for changing filters A spacer which holds the filter in the filter cell and compensates for differences in thermal contraction when cold must be machined to match the thickness of the filter The thickness of the Figure 1 Filter spacer and filter cell spacer must be 14 40 t 0 05 mm 0 567 t The screws press on the slit sections 0 002 in where t is the thickness of the filter For ofthe spacer which acts as springs 2 4 Changing filters 2 ROUTINE MAINTENANCE the nominal thickness of 3 mm the thickness of the spacer is 11 40 mm If the spacer is too thick the filter will be crushed An undersized spacer will not hold the filter The filter wheels must be balanced in order not to overcome the antibacklash springs The little filter w
38. test them Cabling 2 Swap the connections P18 and P19 where the long motor cable plugs into the panel behind the motor controller Then test the mechanism that was not work ing Remember that after you swap the cable you must mentally swap the name so that the software moves the same mechanism If the mechanism is still broken Go to Start gt All Programs gt National Instruments gt Measurement and Automation 10 4 3 Detector electronics 4 TROUBLESHOOTING then the problem is somewhere between the plugs P18 or P19 and the mechanism If the mechanism works then some cable between J18 or J19 and the motor driver is broken The wiring from the motor driver to the connector can be tested since it is open Cabling 3 The connection between the motor driver assembly and the motor can be checked without opening the instrument The cable can be removed The connec tions inside the vacuum enclosure should show this 1 The wires that include a motor coil should have a resistance of about 50 The resistance changes slightly when the motor is cold 2 The switches are normally closed they open when the limit is engaged 4 3 Detector electronics Proper function of the detector electronics requires the detector detector card flexible cables detector controller umbilical umbilical card data cable the data card in the com puter and three power supplies See Table 7 for a block diagram This section describes ways to isolate pro
39. the vacuum enclosure Noise lf the image shows noise that is not synchronous with rows or columns then grounding may be improper See 95 3 1 Check that the power supply for the detector controller uses the same AC circuit as the computer and motor driver We have found that the safety grounds of two circuits in the lab have large RF noise between them Each detector controller is grounded to its box though the screws to the box Check that the controller is screwed into the box Check that the screws on the detector controller are attached to pads that have a jumper to ground lt is impractical to look for noise on the detector controller since the noises of interest are not synchronous with the signal and they are of order 10 uV whereas the signal changes by of order a volt over the period of a pixel 13 4 3 Detector electronics 4 TROUBLESHOOTING Fiber Optic heartbeat LEDs p 5 P100 P200 P300 P400 chan0 chan3 gu chan0 chan chan2 chan3 chan1 chan2 v 2 z LEDs 8 P4 to Computer O ii HEA 3 3V fault Power D LEDs S P3 heartbeat 1 8V OK Fiber Opt sv 3 3VOK Power amp esse Push to enable power indicating LEDs X Figure 3 Indicator lights on the umbilical board and detector controller 5 INSTALLATION Figure 4 Vacuum port left nitrogen ports center and VCR to Swagelok adaptor for the nitrogen port right 5 Installation 5 1 Vacuum and nitrogen interface The pumping p
40. tings Encoder Settings PWM Settings and Synchronization Settings are not applicable Configure the serial port COM1 to use these settings 9600 baud 8 data bits no parity 1 stop bit and no flow control The pressure sensor uses the serial port 5 5 Installing software See nstalling software Spartan IR Camera 5 6 Initialization after servicing Since the stepper motors have no encoders the computer keeps track of the positions of the mechanisms If the motors moved without the computer s knowledge you must find home which is the reverse limit switch 1 Go to the tab forMechanismEngineer in SpartanGUl vi 2 Select a mechanism and press the button Test Home to check the location of the reverse limit switch If the reverse limit is far from zero much more than 40 musteps the mechanism has probably moved A shift of the location of the limit switch is reason for concern Submit this as a problem 3 Press the button Store Home to reset the location of the reverse limit switch 4 Press the button Test Home several more times to verify that the location of the reverse limit is repeatable 5 Repeat for each mechanism 5 7 Alignment In principle aligning the instrument on the Instrument Support Box ISB requires fix Table 5 Alignment of the instrument on the In ing six degrees of freedom Table 5 but Strument Support Box the only two degrees of freedom for which _Pa ameter Adjustment lolerance x amp y t
41. txt to indicate that the mechanism position is changing After finishing a motion the flag is erased and the new position is written to the file Thus the position of the mechanism and whether the position is accurate are both stored on disk to ensure safe recovery from a crash Each mechanism has its own file image ID txt contains the serial number of the last image The image ID is used as part of the name of the image and it must be unique A 4 2 Software configuration These files which are in homeSpartan Configuration contain configuration informa tion spartan txt has computer specific paths An example is in Table 8 The format is that of Windows configuration files The line in brackets specifies the IP number of the computer to which the following information applies defaultOptic vi Figure 15 contains the default mechanism positions for the high res and wide field observing channels mechanismParameter vi Figure 15 contains the operating information for the mech anism which are the controller and axis number to address the mechanism the maximum position counting from 0 the number of steps per position whether to 36 A 4 Software A INSTRUMENT DESCRIPTION Table 8 Example configuration Note the first slash is translated to a colon e g the entry C home Spartan instLog translates to the path C home Spartan instLog default 35 9 70 129 computerName unknown computerName sextans imagePath C ima
42. y P CPp For No and O2 C 1 C 2 4 5 9 and 4 1 for H2 He and Ne respectively The conversion is nonlinear for P gt 1 Torr See the manual for more information A cryogenic charcoal getter pumps oxygen nitrogen and argon which permeate through the Viton o rings The coconut charcoal is glued on the nitrogen cryostat The charcoal getter should keep the pressure low for more than a year Charcoal releases adsorbed gases when warm It does not need to be baked unlike zeolite charcoal does not bond to water Liquid nitrogen cools the instrument The cryostat holds 7 L of nitrogen independent of rotation along an axis perpendicular to the top which is the rotation axis of the instrument on the telescope The nitrogen can be forced out if the instrument is oriented with the filter port facing down several design features control the heat load A multilayer insulating MLI blanket reduces the thermal radiation by a factor of about 100 The MLI consists of 10 layers of single sided aluminized polyimide A thermal reflector reduces the solid angle of thermal JInficon 2002 Operating Manual BPG400 Bayard Alpert Pirani Gauge gy Vacuum Chamber N2 Cryostat Port for Filter Access Charcoal Getter N2 Vent Relief Valve Figure 12 Schematic of vacuum plumbing and nitrogen plumbing 31 A 3 Electronics and cabling A INSTRUMENT DESCRIPTION radiation from the window The G 10 struts have low conduction The
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