Section 6
Contents
1. SHINO auey 31v58 LON 388 1 NOLLVCINDOO I TVNOLLVN 90 HLI INVETI WINN AWONCHILSY NI NOILYIDOSSY IHL Ag ALVO AHOLVAHHSHO ANONCULSY IVOLLdO IVNOLLVN Sisseu 61 ejBurs ur euejdxoeg JWA 1105 1015 8 21 4e u07 SIM IO 1916 JWA ZL 1ejo nuo ydeibo yoeds SHINS 198 oF eds sgoy 599 sde owscubed 190 2 S 2 5 XVME 566 Sensor HK Sensor HK OMS VME8 8 BC635VME MVME2700 1221A XVME 240 MVME2700 1461 XVME 240 OMS 44 4 Temp Mon s OMS VME44 4E OMS VME44 4E 7 1 a indui 42 amp 001 2 places E 4 L 8 lt 761 AMJIA LNOH3 sisseyD 3IJA 1e onuoo 1ueuoduio2 SHINS Section 6 Drawing 89 NOAO 4201 4013 107 GNIRS Service amp Calibration Manual The layout and packaging of the devices in crate 4 is shown in Dwg 89 NOAO 4201 6 5 4 Ancillary Crate Crate 4 4014 qbley 6 61 sisseuo 1 61 dOL jno e7 sisseyy 3190 LON 1o ues MIA 3dis 25585 S3M IO d LO LZEDAD 1ejonuo2 einer ues ueueA2. CV tin 10100 seconds Damping Factor dPnGFctr default 0004 speed of response lower faster output on SSCS Jong Canto ype is ONO Ramp and Soak raw Sone 56 3 lt lt tte Analog Output Option secs Remote Setpoint Option push ENTER twice for Standby Disable once more for Run Enable press MENU to access the top level menu items use ENTER to select sub menu items GNIRS Service amp Calibration Manual 113 Section 6 6 6 System Failures This section outlines steps required to respond to plausible system level failures They comprise Power failures Coolant failure Network failures Cryocooler system failures Bad weather 6 6 1 Power Failures Power failures can be failures of mains or UPS power only Mains power only In responding to mains power failures it is important to understand that there are three critical sub systems within GNIRS that are powered off mains These are the cryocooler heads the thermal enclosure fans and the ethernet switch One should also recognize that in most cases mains power failure will also stop coolant flow to the thermal enclosur
3. SAM IO 5 un o Adding bu 5 5034 SAM IO uv3d Me M 5 5 SAM IO e e GUD LO IZEDAD 9101 ISMO 10 495 UEUEA EON met lej ojuoz 1101488 1eMog 7 7 5 5 SAM IO Lo anga ST Section 6 Drawing 89 NOAO 4201 4014 108 GNIRS Service amp Calibration Manual Bench Temperature Control The bench temperature controller is a self contained circuit within the ancillary crate 4 This controller operates from line AC power and without computer control it is completely autonomous A CN77 Process Controller operates as an analog controller using a P I D algorithm and is preprogrammed to control the bench with a variation of less than 1K See Sec 7 3 for details on the operation and programming of the CN77 Two 1N914 diodes TD28 and TD37 are located on the bench see Drawing 89 NOAO 4201 0814 for their location for sensing its temperature Both are wired to the Bench Temp Controller but only one is selected for use as the monitor The other can be selected by opening crate 4 finding the toggle switch on the Bench Temp Controller PCB ref Dwg 89 NOAO 4201 4410 and changing its position The analog output of the CN77 has a range of to 10V The output goes to 4 parallel A
4. SISLAR dO NOLLYDOSSY a SNIVIA H Sdn MOOL SIHL AHOIVAHHSHO ANONCULSY IVOLLdO IVNOLLVN ej A Ang MOSL yeay pue 602 sueJ iebueuox3 JL or 5155 eyo yunoubaer eroe uuuo2 6 H Aq 08 Sid pue SAM sissey aunou 6 5155240 6 eue dx eg 8 21 1145 sisseyo JWA n6 sisseyoqunounjse 6 Bulpunoly 2v Jed SNIVIN sqi 1uBie M OV Drawing 89 NOAO 4201 4010 Section 6 102 GNIRS Service amp Calibration Manual Lcid i gene r re ane a a 020t LOZt OVON 68 man s H3409 TVLN3INOHIAN3 Ayo 68 5 3359 0625 2 1825 41 05 5 5 t EH as wes viva 3wvas 199999 i tris Tvang SBOLOW SAM 1745 39715 1903 SAM ino 9725 0505 SIM FE Ele mesus pojend 369 Drawing 89 NOAO 4201 4020 Section 6 103 GNIRS Service amp Calibration Manual 6 5 1 WES Stepper Motor Control Crate 1 This crate ref Dwg 89 NOAO 4201 4011 was provided by the IfA for controlling the 4 P
5. NOTE Saturation of the molecular sieve in a short time may indicate other problems such as a leak or excessive outgassing resulting from internal contamination or insufficient evacuation prior to the cooldown The evacuation backfill steps in section 4 2 2 are necessary to clean out the instrument as best as possible particularly if the instrument had been exposed to air particularly in a humid environment for more than a minimal period WARNING Do not vacuum bake the molecular sieve by heating up the instrument bench to 60 C or so with the bench heaters while pumping on the vacuum jacket Such a temperature is insufficient to clean out the sieve and the efflux of contaminants from the sieve may be deposited on the optics or other delicate components of the instrument 6 5 Component Controller Thermal Enclosure Troubleshooting Thermal Enclosure Power The procedure for connecting and powering the Component Controller Thermal Enclosure is given in Section 4 1 1 GNIRS Service amp Calibration Manual 100 Section 6 Thermal Enclosure Layout The Component Controller is a standard Gemini Thermal Enclosure with fans and Glycol cooling loop in the base cooling air plenums up the sides two power strips for MAINS and UPS AC power and a connector panel for all cabling at the base There are 4 boxes or crates of electronics within the CC TE ref Dwg 89 NOAO 4201 4010 1 Crate 1 WFS motor amplifiers and power supply provided by the If
6. and the outgassing products from the bakeout will be carried out by the flow If the system is under vacuum GNIRS Service amp Calibration Manual 98 Section 6 when bakeout is initiated a rise in pressure is normal The procedure is described in section 4 2 3 3 3 6 4 3 Cold Vacuum Problems Barring a catastrophic failure of a vacuum seal vacuum problems arising when the instrument is in operation are likely to manifest themselves over an extended period giving some flexibility in dealing with them Under normal instrument operating conditions the molecular sieve which is thermally strapped to the second stages of cryocoolers 1 amp 2 should be at a sufficiently low temperature to cryopump most residual gases in the instrument or any outgassing products The most likely causes of cold vacuum problems are e Contamination of the vacuum jacket by hydrogen helium or neon These gases have a sufficiently high vapor pressure at the temperature of the cryocooler second stage 15 that they will not be cryopumped e Contamination of the molecular sieve primarily with H20 so that it loses its effectiveness e Excessive outgassing or a leak in the vacuum jacket Although these products will be cryopumped by the molecular sieve they can raise the transient pressure sufficiently to provide a thermal conduction path to the warm instrument housing Eventually the molecular sieve may become saturated 6 4 3 1 Symptoms The most l
7. 6 Troubleshooting Procedures This section covers procedures for diagnosing and solving common problems with GNIRS Of course it is our expectation that even common problems will be relatively infrequent In general there are two main ways of identifying problems One is the diagnostic screens described in section 6 1 which among other things monitor system health through a variety of sensors and procedures The health of the instrument or sub system can be categorized as good warning or bad Any state other than good should be checked out in some cases it is possible to continue operating effectively especially under warning conditions but you should always verify the exact circumstance first The second indicator of problems is the science data stream Always look at the data as they are taken The appendices to the User s Manual indicate what data should look like for common configurations If the actual observations look different make sure that this is consistent with random variation and does not have some other cause In particular mechanism failures will show up first as night sky line spectra that do not match the appendices or as excess or deficient background levels Other things to look for are bad images possibly indicative of incorrect focus excess flexure or guiding problems and excess noise indicative of controller or grounding problems GNIRS Service amp Calibration Manual 80 Section 6 6 1 Diagnost
8. A 2 Crate 2 GNIRS motor amplifiers and power supply cryohead motor power 3 Crate 3 split VME crate for the EPICS electronics and the WFS electronics 4 Crate 4 Ancillary crate The Ancillary Crate contains 3 stand alone electronic devices the power supply provided by the IfA for the SDSU 2 electronics mounted on the dewar an Omega CYC321 01 temperature controller that controls the WFS Detector temperature provided by the IfA and the Varian senTorr pressure gauge controller In addition the GNIRS Bench Temperature Controller is also packaged within crate 4 The Bench Temp Controller uses an Omega CN77 process controller mounted in the crate 4 front panel while inside the crate is a 28V power supply and 2 PCB s with power op amps that supply the heater power to the GNIRS bench The main connector panel of the Component Controller TE with connector labeling is shown in Dwg 89 NOAO 4201 4020 and 4255 Detail of the TE internal cabling is found in Dwg 89 NOAO 4201 4500 GNIRS Service amp Calibration Manual 101 Section 6 g3s 3734 48 31 0 ganssiinigd 16 OLOF LOCE O VON 68 en 5 ane Du TEL UE aby gp 10 NZ 92249 ejqesr eansopou peo p EN nose einso ou3 qjueuoduio 1 UL 101040091 ONIMWHO LON wayshs NOLLVINNOd HONHIOS IVNOLLVN
9. GNIRS Service amp Calibration Manual 115 Section 6 Turn the problem head off but at a point in its cycle where gas is flowing through it You should turn off the other heads so you can hear better and then jog the head by connecting power briefly Do this until you hear gas flowing through the head At this point you can turn on the heads on the opposite side of the instrument to maintain as much cooling as possible Wait about 5 minutes then try starting the head If the outlet gas is still cold you may want to try again wait a little longer e Ifyou are unable to get the problem head to run correctly it is marginally possible to run the instrument with 3 heads Turn off the problem head make sure that gas is not flowing through it now and turn the other 3 heads on In general a coldhead will not freeze up spontaneously it will do so only if it has been stopped for a while The solutions outlined above may also help restart a contaminated coldhead but unless the contamination is purged the problem may reappear Low compressor pressure If the compressors are providing insufficient gas flow the cryocoolers will not be able to maintain proper instrument temperature This will affect the science detector and the bench temperature The first obvious symptom will probably be a loss of detector temperature control error condition on GNAAC temperature monitor although the bench may start deviating from nominal before that If
10. I TN NN Data Headers NORMAL Observation Setup Observation State Integration Time Secs Ser iotogration pen IDLE RUNNING Controller State Installed Array Size tows by Mel cals RUNNING Current Readout Size Rows to be read 1024 p Ita iind dde em Cols to be Read 1024 5 11 uCode Waveform Generator Program 12 ucode Path dlirim0 gn 4 ucode NAAC VggCl1 uCode Name gnAII 1024xSUO1 4u Vggc12 cmd Path dlirim0 gn 4 ucode NAAC wet GNIRS Service amp Calibration Manual 89 Section 6 Screen Regions 1 Image Setup Not used with the DHS 2 Observation Setup Shows current state of observation parameters such as coadds low noise reads digital averages number of pictures and integration time In addition the integration time can be modified here The obsSetup CAD must be run for the change to take effect Do Obs Setup button or from Observation Cntrl in Setup Commands area The Observation can be started stopped or aborted here also GNAAC Observation Setup Display Integration Ti Digital Avgs Low Noise Rds Co adds of Pictures Proc Mode HM o HK Process State EE 1 Header Detail ED Header Timing 1 Array Readout 1024 3 uCode Waveform Generator Program Displays the current and path 4 Overall Health Disp
11. N77 Process Bench Temp Controller Setup DIP Switch Settings Process 1 1 5 ON or 10Vmax 3 5 ON Control Description __ _ Operation Menu Display Setting Default Remarks 2 SePon SP page22ifID NumberDisabled defaut px ____27 __________ ___ ___ _____ ________ 2 _______0 1 0 __ set voltage range to agree w DIP switches EMP Unit TC really scaled to be K FLtr CnSt lefault 0004 for PID select 0001 0002 or 0004 SC OF es In 1 rd 1 In 2 rd 2 ALAr 1 EnbL dSbL 5 dEv LtcH UnLt Do 0 0 contact closure _______ ___55 _______ Aamf towvaue __________ A 38 Loop Break Alarm 2 tpt Se Se Eoo o LO Eoo o HI 4 20 So le dret rvrS rS dSbL Adaptive Control ___46 ________ _ 0 0 Reset Setup 0 Rate Setup rAtE StuP 49 Damping Factor dPnG Fotr 52 On OF Pid dret rvrS 5 EnbL dSbL dSbL EPmpotioalBand ___55 f o CydeTme CCL NE ____56 __________ _ dEAdbAnd only if Control Type is ONOFF ___58 RampandS
12. Setup and Do DR ROI Setup buttons NIRI WFS Top level control Simulation Mode The WFS dm windows allow the user to run the WFS mechanisms for engineering purposes The A amp G system will run the WFS on the telescope GNIRS Service amp Calibration Manual 9 Section 6 There are two major areas Wavefront Sensor and Engineering The engineering area runs the system at the low level without the use of EPICS CAD records This is useful but can do harm to the system The other area uses the standard CAD CAR record structure to run the system The Wavefront Sensor CC is most similar to how the A amp G will run the system NIRS WFS WFS Components Controller Min Stree Ee COREE mm MBLC AEE mm Simulation Mode 15739 Lim BCE BY mm WFS wfsBeam 0 True GNIRS Service amp Calibration Manual 92 Section 6 6 2 Mechanical Operation Diagnostics 6 2 1 Home Switch The Home switch is used for datuming for all the rotary and linear mechanisms The first part of the datum process involves searching for a home transition at high speed Once the rough location is found the mechanism is moved a distance away that is many times bigger than the mechanical backlash The last step is moving back toward the home switch at a slow speed Once the transition is found the location is set to the zero step position The home switch is not used during normal operation for the rotary and
13. ables the ZSO Mini driver 4 selectable inverters for the hardware inversion 0 or 1 if needed of the following ZSO Mini control signals a HOME b BOOST c DIR 5 and the pull up resistors required by the ZSO Mini opto isolated interface Coldhead Motor Drive In addition the 110VAC to 220VAC step up transformer and the AC capacitors that supply the lagging phase for the Leybold RG 5 100 coldhead motors are also in crate 4 ref Dwg 89 NOAO 4201 4202 There are four 3 phase outputs one for each cryohead motor on the GNIRS dewar with its own resettable circuit breaker on the rear of crate 4 Front panel switches select either manual OFF ON or computer controlled OFF ON Some additional inverters and R C filters provide lowpass filtering and switch debouncing for the control signals going to the XVME 240 digital I O board in the EPICS VME crate 6 5 3 VME Chassis Crate 3 The layout of crate 3 and the locations of all VME boards in the VME backplane is shown in Dwg 89 NOAO 4201 4013 GNIRS Service amp Calibration Manual 106 Section 6 _ EP LZ anum gasva1as A8 3 199 ganssiiwmd 16 avoio 5NISn LOCt O VON 68 _ 48 Ed NOisag 37706 ERE no e 5155299 AWA 12286 POO HMW 86 dIS Nid snig 4181345 2 E d PON 621 SJAVI9JJou02 JUsUOdUWIO4 404 pesnun peqpee S
14. atings Filter Wheel 2 p mm Selected filter slit ea Selected width Selected Prism GNIRS Service amp Calibration Manual 84 Section 6 4 Observation Control commands Start stop and abort observation here below OBSERVE DHS Data Label CC Screens Main Component Controller window DC Screens Main Detector Controller window NIRS System status information Debugging Set global or local debugging level Sequence Commands guide endGuide verify and endVerify commands 10 Lookup Tables Filter wheel tables 11 Temperature control Detector temperature control and cryo cooler operation 12 Temperatures Temperature monitor 9t GNIRS Service amp Calibration Manual 85 Section 6 The next major component of the system is the Components Controller This is where all functions related to temperature pressure and mechanism position can be controlled or monitored ccTop dl Motors gt Temperatures Pressures Observe Car Records The buttons on the Components Controller window are listed below 1 System Cad Records This drop down menu contains the init reboot debug test diagnose and cryo Head CAD test windows 2 Temperatures This button starts one of three temperature monitor windows A right mouse click will drop down a menu for the user to pick one of the windows below GNIRS Service amp Calibrati
15. ature too high detector temperatures may also be too high Cryocooler failure Check that all four heads are operating Check that inlet outlet gas lines are at similar temperatures on all four heads outlet will be different than inlet Other indicators are very different temperatures on the coldhead first stages or the thermal busbars If one head is running but not working correctly turning it off will not change cooling performance and may even help slightly because gas flow is not adding heat This is a useful means of verifying the diagnosis and may permit continued operation since 3 heads can maintain a stable temperature in some cases Cryocooler supply compressor failure This is a facility problem if present diagnose using Gemini supplied procedures o Bench temperature controller malfunction Check set point showing on controller panel Check programming parameters 7 3 o Bad vacuum see 6 4 Bench temperature too low or bench temperature varying by gt 1K o Bench temperature controller off or malfunctioning See 7 3 e Bench temperatures OK but science detector too warm GNIRS Service amp Calibration Manual 95 Section 6 Cryocooler failure heads 1 or 2 only Check as above o Incorrect setting on detector temperature control Check EPICS screen and change if necessary o Bad vacuum see 6 4 Bench temperatures OK but science detector too cold o Incorrect setting on detector temperature co
16. but a guide to diagnosing and fixing the most likely sources of vacuum problems in GNIRS 6 4 1 Diagnostic Techniques Three tools available for vacuum diagnostics with GNIRS are e The Convectorr vacuum gauge installed on the instrument and read out with the controller in the Component Controller Thermal Enclosure or on the Status Screen if the control software is running e The Cold Cathode vacuum gauge installed on the instrument can also be read out directly from the controller or from the Status Screen This can be used only at pressures below a few mTorr and is the primary vacuum monitor when the instrument is cold Contamination in the gauge may prevent it from turning on until pressures are in the 10 to 10 Torr range e Helium leak detector or Residual Gas Analyzer These are extremely useful for diagnosing and locating physical leaks but are not part of the instrument complement and will be assumed as part of the Observatory infrastructure 6 4 Ambient Temperature Vacuum Problems Vacuum problems are most likely to occur during the initial pumpdown after opening up the instrument since a bad O ring seal the most likely cause of a leak can easily occur through contamination on the O ring or uneven tightening of the seal The large end shells are particularly susceptible because of their size Unfortunately the rate of internal outgassing is also highest after the instrument has been opened and exposed to air Following the proce
17. d to the Bench Temp Controller but only one is used as the monitor The other can be selected by opening the box finding the toggle switch on the Bench Warmup Controller PCB ref Dwg 89 NOAO 4201 8100 and changing its position The CN77 process controller has two LED displays the upper display red LED is the Process Value PV which is the bench temperature and is displayed in Kelvins the lower display green LED is the Setpoint Value SV and is the desired temperature in Kelvins Six front panel white lights are ON if heating is enabled and AC power is being applied to the power resistors Another front panel red light is ON if the sensed temperature exceeds the programmed limits for an alarm Typically the alarm values are temperatures less than 50K and greater than 320K Two front panel toggle switches allow the selection of 3 other SV values which are preprogrammed within the CN77 This feature is called the remote setpoint both switches down selects the default SV as programmed first with the CN77 menu buttons 1 Attach cable W719 from the rear of the warmup controller to J719 on the dewar Attach the box power cord to MAINS power 2 Turn on the AC power switch to start operation Verify the SV green LED display is set to 300 0 3 The controller will immediately apply warming power to the warmup power resistors with a duty cycle appropriate to a linear increase in temperature Monitoring the PV red LED display temperature durin
18. ding O ring o With clean gloves carefully check the O ring and the mating flange for debris and ensure that both are clean o debris is found reassemble the part ensuring that the O ring seats evenly e audible leak is found resume pumping on the dewar until the previous ultimate pressure is reached then close the valve and record the pressure vs time again o Ifthe pressure increases more slowly than on the first test outgassing is the likely cause o Ifthe pressure rises at the same rate as before there is probably a leak e is suspected use a He leak detector to determine the location If the leak is in an O ring joint follow the procedure above to clean and replace the O ring NOTE Do not spray solvents such as alcohol or acetone on suspected O ring joints to detect leaks This can damage the external finish and the O ring and will affect the calibration of the Convectorr gauge e If outgassing appears to be the limiting factor backfill with and re evacuate one more times following the procedure in section 4 2 3 3 72 This will help flush out tenacious molecules One should reach lower pressures in a given pumping time If this is the case one can then proceed with the backfill bakeout procedure 6 4 2 2 Pressure Rise after Starting Bakeout We recommend that bench bakeout be done with the instrument backfilled with since one will be in the viscous flow regime when one begins the pumpout
19. dures for evacuation and purging section 4 2 2 will flush out a lot of the tenacious molecules and minimize the amount of outgassing GNIRS Service amp Calibration Manual 97 Section 6 6 4 2 1 Slow Pumpdown If the pressure in the instrument does not come down at its normal rate see section 4 2 2 for recommendations on establishing a baseline pumpdown timeline there are several diagnostic steps to distinguish outgassing from a leak In general a vacuum which is limited by outgassing will show a slow sometimes very slow continuing decrease in pressure with time while pumping whereas a leak will stabilize at a fixed value If the pressure stabilizes at a high value 100 mTorr or higher after only an hour or so of pumping a leak is quite likely At this point one would likely have not yet started the backfill or bakeout procedure e Close the vacuum valve on the instrument and monitor the pressure for 30 minutes or so recording the presumed increase as a function of time e While the valve is closed check around the O ring seals particularly those that might have been opened during maintenance listening for leaks It will be helpful to disconnect and turn off the vacuum pump to minimize extraneous noise Large leaks particularly into a large hollow chamber can be quite audible Ifan audible leak is found it will be necessary to bring the instrument back to ambient pressure with and remove the part sealed with the offen
20. er Setup DIP Switch Settings Process 1Vmax 1 5 or 10Vmax 3 5 ON Operation Menu Display Setting SP 22 10 Number Disabled seroma 5 id 0 1 0 fst vatage range to agree wi awitches PS Fier Constant Furenst 000 for PID select 0007 0002 or 004 inu Scale ost T the natural gain Pre tives Tis reading counts rina valve iV the natural gain o LLL LL sss Ts reading counts 7 mmu rS sae 1 Pn sss Pn racer condition A38 T gt Toop Break Alarm 707227 eat se Control Type On OF Pld Relay SSR or Pulse Option iy arto Type is ONOFF Proporional Band Pro band ony non AUTO PI Reset Setup 0000 Rate Setup ___ set 000 0 seconds to sable
21. es and high pressure helium flow from the compressors to the cryocoolers If the main power interruption is brief less than a few minutes there is no need to do anything specific immediately Data being taken will probably be lost however Once mains power is restored it will probably be necessary to restart the EPICS displays and telnet windows using nirsStart to re establish communications If however the power failure is more than a few minutes long the electronics enclosures will start to overheat and should be powered off UPS switches off on both The first symptom of overheating is a bad ADC health indicator in the GNAAC control window Once the UPS power has been turned off further response is the same as for both mains and UPS power failure below Mains and UPS power If all power is lost then the correct response is to turn off the UPS power switches on the thermal enclosures Once power is completely restored the system should be re initialized using the start up procedures described in section 4 1 In addition if the power is off for more than a couple of minutes it is important to verify that all four cryocoolers are functioning correctly see 6 6 4 below UPS power only If only UPS power is lost turn off UPS power on the thermal enclosures and turn the switches on again when UPS power is restored and all external computer systems are running again At this point the procedures are the same as the start up procedur
22. es in section 4 1 Note that all mechanisms will need to be re datumed and the detector temperatures will need to stabilize This procedure is the same whether UPS power is off for seconds or many hours GNIRS Service amp Calibration Manual 114 Section 6 6 6 2 Coolant Failure If there is a failure of the glycol water coolant system the thermal enclosures will eventually overheat The likely first symptom of such overheating is a bad ADC health indicator on the GNAAC control window If such an indicator appears make sure that the problem is indeed overheating and not some other problem before proceeding If coolant failure is the problem shut down the UPS power to the electronics in both enclosures and restart according to Section 4 1 once coolant is flowing again Do not shut off mains power in order to keep the cryocoolers running 6 6 3 Network Failure There are such a variety of possible network failures that it is difficult to catalog specific responses for each case However the following guidelines should be helpful In general the individual sub systems are self contained so loss of communication does not necessarily cause them to fail Wait for the network problem to be fixed and attempt to re establish communication with the instrument computers use nirsStart to re start EPICS and the telnet windows If you cannot communicate with any computer the problem may be in the ethernet switch or its connections e If
23. g the 24 period is recommended When the RAMP feature is enabled the left most digit of the SV will be flashing The RAMP feature works by storing the end point SV in this case 300 0 but during the 24 hour ramp time changes the SV from the beginning temperature to the final temperature on a regular cadence At turn on the SV will immediately change to 78K if the starting point is 77K and will increment by 1 every 24 60 300 77 6 minutes more or less When within 2 degrees of the final SV the process controller switches to normal PID control at the final SV 300 0 K 80 F typically for GNIRS GNIRS Service amp Calibration Manual 111 Section 6 The front panel of the Warmup Controller box provides additional monitor points The two yellow black pairs of banana jacks are the direct outputs of the temp sensing diodes with LM324 buffering and without conditioning to engineering units e g Kelvins The triple banana jacks red black orange a source of 15VDC limited to 200mA from the internal AC DC power supply An Excel spreadsheet for recording all the programming values of the CN77 is provided as Warmup_CN77setup xls Programming CN77 is further described in Sec 7 3 GNIRS Service amp Calibration Manual 112 Section 6 Control Description Manual Pg 22 22 27 29 30 31 33 34 35 36 38 42 43 44 47 48 49 52 53 56 58 62 65 82 CN77 Process Warmup Controll
24. hytron step motors within the OI WFS The motors and drivers used in the WFS are the same as used by the GNIRS spectrograph The power supply is designed by the IfA as an unregulated motor supply hence the massive transformer in this crate 89 NOAO 4201 4011 E 5 E 8 8 SIDE VIEW REAR VIEW DO NOT SCALE DRAWING 3420 m3 9 sanya 9 JEM INON SBA gt Jen 9 VIEW 19 rackmount chassis 19 depth 5 1 4 height FRONT VIEW Jeng 1 IMON deo aa Z L 1 1 Drawing 89 NOAO 4201 4011 GNIRS Service amp Calibration Manual 104 Section 6 6 5 2 Stepper Driver Chassis Crate 2 The layout of crate 2 is shown in Dwg 89 NOAO 4201 4012 AWOLXANHSHO AMONOWLSY THOTUdO THOT LUT vLLINBZM ueidoov 1uBleu 9 61 sisseuo junounpel 61 AMAIA dOL Driver M Board zal pue das eH Joop OOOO vor 5527 2517 527 eal VeL AS al FLLVIBEM Jeng Jovi ueidoov 581 Lb eri an E
25. ic Windows The diagnostic windows for GNIRS are EPICS dm screens which can be used to monitor and modify EPICS variables Type nirsStart script located in BASE bin solaris to start the top dm screen and the 4 console windows that are connected to the four vx Works machines associated with GNIRS The diagnostic windows are an interface to the CAD CAR APPLY records see Software Manual for definitions and explanations and also show the current status of the system Several display buttons will display a menu when right clicking with the mouse Some of these menus are dynamically loaded so if the system is rebooted or the menu is reloaded after the dm screen is already displayed the right click menu won t be updated This is easily fixed by exiting the affected window and re displaying it from its parent window The window shown below is the top level engineering window for GNIRS nirsseqTop dl Instrument Sequencer Components Controller Detector 11 Wavefront Sensor On this window there are four buttons that correspond to the four major components of the system 1 Instrument Sequencer The instrument sequencer controls the system most like the OCS would It communicates with all the other systems except for the Wavefront Sensor 2 Components Controller The Components Controller monitors temperature and pressure It also controls the mechanisms the detector and bench temperature and the cryo moto
26. ikely symptom is a slow rise in the instrument pressure as measured by the cold cathode gauge any pressure sufficient to be measured by the Convectorr gauge would produce evident and serious symptoms During the initial stage of this pressure rise the bench and detector temperatures should remain at their normal values since there is reserve cooling power available The heater power on the temperature controllers particularly for the detector will decrease with time as the additional thermal loading comes into play Eventually the heat load will become so large that the cryocoolers will be unable to maintain the operating temperature 6 4 3 2 Solutions The only solution to a cold vacuum problem is to re evacuate the instrument to maintain a thermally insulating vacuum Depending on the cause of the problem and details of the instrument scheduling for example it may be near the end of a long run after which the instrument will be unscheduled for a while there are a couple of approaches one may take 6 4 3 2 1 Emergency Cold Pumping If the situation and scheduling permit it may be possible to pump on the instrument during the day while maintaining the cryocooler operation thus effectively avoiding any GNIRS Service amp Calibration Manual 99 Section 6 lost time If the instrument can be accessed so an oil free backing pump be installed on the on board Turbopump the vacuum jacket can be evacuated on the telescope Refer to sect
27. ion 4 2 2 for Turbopump operation procedures This procedure has some potential for success if the problem resulted from a very slow external leak or diffusion of He gas from the LN precool lines into the interior of the instrument It is less likely to provide more than temporary relief if the molecular sieve has been saturated or contaminated since the sieve will not give up its load while still cold If a leak has developed in the LN precool lines the relief afforded by cold pumping will also be of short duration If a He leak detector can be connected to the Turbopump output one may check for the presence of significant He in the instrument or even attempt to locate leaks in the vacuum jacket However such efforts may go beyond those one would want to attempt with the instrument cold and on the telescope 6 4 3 2 2 Warming Up the Instrument If the cold pumping procedure section 6 4 3 2 1 is ineffective or a He leak test suggests a significant leak from the LN precool lines then the instrument must be warmed up and re evacuated after locating and repairing any leaks If no leaks are found and it appears that the molecular sieve has becomes saturated simply warming the instrument to ambient temperature and re evacuating is not sufficient since the sieve must be heated to 200 C in a vacuum for at least several hours to be fully restored In such a case we recommend removal of the molecular sieve and a vacuum bakeout section 5 3
28. lays health of the system 5 Array Setup Displays detector status such as the activation uCode download state and bias level These values can be changed from the Array Setup or Observation Cntr windows 6 Array Voltages Displays pertinent array voltages GNIRS Service amp Calibration Manual 90 Section 6 7 Apply Cad Test Screen Right click to pull down a menu that allows the user to choose one of the diagnostic CAD windows 8 View Errors Displays most of the APPLY CAD and CAR error status and messages 9 Clear Errors This button clears the errors in all of the APPLY CAD and CAR records in the Detector Controller 10 Additional Screens Right pulls down a menu that has a list of useful windows 11 Raw HouseKeeping Two windows that show the value of every monitored voltage in the system 12 Setup Commands Bring up windows that allow the user to setup all the necessary parameters in the Detector Controller Array Setup Cntrl Download ucode and set array voltages Observation Cntrl Set array activation digital averages co adds number of pics Proc mode HK process state header detail header timing readout size and integration time Data Image Cntrl Setup simulation patterns or array readout The associated CAD must be started for any changes to take effect They can be run from their respective windows or from the Do Array Setup Do Obs
29. linear mechanisms once the datum is performed If problems occur with any of the mechanisms during operation the mechanism can be re datumed to reset the home position There are two home switches per mechanism The function useAlt can be run in the Components Controller console window to switch between the home switches during operation of the system useAlt motor 0 1 0 primary home switch secondary home switch The initial state of the home switch and other motor related parameters are in the BASE CC pv gnirsConfig configuration file The function mstatus will display several useful values related to the motors Type mstatus motor detailed 0 1 In the Components Controller console window Below is the list of motors and their corresponding motor number Cover 0 Filter wheel 1 1 Filter wheel 2 2 Slit slide 3 Decker 4 Acq Mirror 5 Prism xdisp 6 Grating 7 Camera 8 Focus 9 GNIRS Service amp Calibration Manual 93 Section 6 The motor numbers are used in several of the command line diagnostic routines 6 2 2 Limit Switch The linear and binary mechanisms have limit switches The Rotary mechanisms have wires leading to the dewar that are connected to the limit switch inputs of the OMS card but are tied rigidly together inside the dewar The function of the limit switches varies slightly for the linear and binary mechanisms If the hard limit at the end the mechanism is driving to gets actuated the po
30. mal expansion See section 5 2 for more details on these procedures GNIRS Service amp Calibration Manual 116 Section 6
31. n Driver M Board Driver M Board Jeuuosuen IT mi umo oo 1969 varo 43930 SNL e roodo cdd b olim 100 river M Board ueidoov Drawing 89 NOAO 4201 4012 Section 6 105 GNIRS Service amp Calibration Manual Stepper Motor Control The 9 cryogenic mechanisms within GNIRS and the external Environmental Cover are driven by 200 step hybrid step motors The mechanism motors are cryogenic rated VSS52 steppers from Phytron while the Environmental Cover stepper is a less expensive motor from API Motion All step motors are driven by Phytron ZSO Mini 42 40 motor drivers 28VDC power supply provides the 28V power and a common backplane provides the interconnections Between the motor output connectors J76x and the interface to the OMS VME44 motor controller boards ref Dwg 89 NOAO 4201 4210 are 4 Mechanism Hard Stop circuit PCBs Each Hard Stop board supplies several enhanced features for the control of the mechanisms 1 for mechanisms with HOME positions selection of the primary or backup switch 2 for mechanisms with motion limits detection of the Hard Limit switch closure and immediate disabling of the appropriate ZSO Mini driver 3 fora mechanism that has hit a Hard Limit disabling the current motion DIR direction and enabling only the reverse DIR direction this also re en
32. ntrol Check EPICS screen and change if necessary e Bench temperatures OK but OIWFS detector too cold o Detector temperature controller not turned on Programming of this controller is not covered in this manual GNIRS Service amp Calibration Manual 96 Section 6 6 4 Vacuum Troubleshooting Proper operation of GNIRS is dependent on maintaining a high vacuum inside the instrument Because of the large surface area even a small degradation of the vacuum can result in a conductive heat load on the main bench The bench thermal control relies on some headroom between the first stage cryocooler temperature and the bench set point and this will also provide some cushion for small conductive heat losses However if the vacuum degrades to the point where the cryocoolers cannot maintain the bench set point temperature the operation of the instrument will be compromised The two predominant mechanisms for degrading the vacuum are diffusion of gases from the interior surfaces and permeable materials within the instrument and permeation of gases from the external environment into the instrument We will refer to these processes as outgassing and leaks Although leakage occurs at a low level because some materials particularly O rings have some permeability the major concern is flow through a physical gap such as a poor O ring seal or hopefully unlikely a cracked weld This section is not a comprehensive manual on vacuum techniques
33. on Manual 86 Section 6 3 Pressures The pressure monitor window is displayed with this button Only two of the three sensors are actually in the system 4 NoOps This drop down menu contains the Gemini required CAD records that have no function in the Components Controller 5 System CAR Records This displays a diagnostic window that shows the state of all the CAR records in the system in a hierarchical format GNIRS Service amp Calibration Manual 87 Section 6 6 Mechanisms Starts a display window that will allow the user to run any of the CAD diagnostic windows related to the ten mechanisms motorsal Motor Cad Screen GEE eee ENEIICHE cover ee pS eee M An example of one of these windows is shown below GNIRS Service amp Calibration Manual 88 Section 6 motorcontrot di xdispControl Result e on Client ID nine Vos pM applyC CAR record State Client ID me Message 7 Park This performs a park command on all ten mechanisms 8 Datum This performs a datum command on all ten mechanisms 9 Close Close this window The Detector Controller engineering display is displayed below Ww Overall Control Raw HouseKeepin ym M Setup Commands Data Path Ww Image Filename IT
34. osk rAMPSoAc PP Rap det 0 Soak EUER Mp ____ min input value mV the natural gain gives this reading counts max input value mV the natural gain gives this reading counts 43 a lefault 0004 speed of response lower faster fo push ENTER twice for Standby Disable once more for Run Enable press MENU to access the top level menu items use ENTER to select and enter sub menu s GNIRS Service amp Calibration Manual 110 Section 6 6 5 5 Warmup Controller The warmup controller is attached to GNIRS at a dedicated hermetic connector J719 on the dewar The Controller uses a preprogrammed P I D algorithm and a RAMPed output function to increase the temperature linearly in 24 hours to 300K The CN77 has an OFF ON output that controls simultaneously 6 power solid state relays SSRs Each SSR applies 110VAC to one of 6 circuits of 50W power resistors mounted on the bench with 8 resistors per circuit The equivalent resistance of each circuit is 70 Ohms so each circuit dissipates 170 Watts on the bench when energized The total power dissipation is just over 1000 Watts Each circuit is individually fused with a resettable circuit breaker on the rear of the box Two 1N914 diodes TD11 and TD26 are located on the bench see Drawing 89 NOAO 4201 0814 for their location for sensing its temperature Both are wire
35. pex PA26 power op amps set for a gain of 2 8X Each output applies to 28 26VDC to one of 4 circuits of 50W power resistors mounted on the cryohead thermal distribution bars with 2 resistors per circuit for each cryohead The equivalent resistance of each circuit is 15 Ohms so each circuit dissipates up to 50 Watts at each cryohead The total possible power dissipation for temperature control is just under 200 Watts The 77 process controller has two LED displays the upper display red LED is the Process Value PV which 18 the bench temperature and is displayed in Kelvins the lower display green LED is the Setpoint Value SV and is the desired temperature in Kelvins A front panel yellow light is ON if heating is enabled and AC power is at the 28V power supply Another front panel red light is ON if the sensed temperature exceeds the programmed limits for an alarm Typically the alarm values are temperatures greater than 80K and less than 30K Two banana jack testpoints have been added to the crate 4 front panel They connect to a 0 1 Ohm 25W resistor in series with the 28VDC going to the power op amps This provides a monitor of the current applied to heating the bench Series 10kQ resistors on each banana jack protect the 28VDC from accidental shorting An Excel spreadsheet for recording all the programming values of the CN77 is provided as Bench CN77setup xls GNIRS Service amp Calibration Manual 109 Section 6 C
36. rs GNIRS Service amp Calibration Manual 8l Section 6 3 Detector Controller The detector controller controls and monitors all functions related to taking an image 4 Wavefront Sensor This displays the windows which control and monitor the mechanisms in the Wavefront sensor 5 Help The help button will give a description of what all the colors on the windows correspond to 6 EXIT Kills all dm windows GNIRS Service amp Calibration Manual 82 Section 6 The Instrument Sequencer button on the main window displays the window shown below 5 4 0 Gemini Near InfraRed Spectrograph System Status Errors Command Status Errors Subsystem Connection status Detector Controller has connected gt Subsystem Messages NIRS System Commands Client ID gt Debugging Tables Temperature Control Temperatures This window shows the health and status of the system as a whole It is also the location where global commands can be run Important regions 1 Apply This controls the top level apply for the whole system right click menu 2 NIRS System Commands Marks and starts the global GNIRS Service amp Calibration Manual 83 Section 6 3 Mechanism Control Commands Change position of individual mechanisms does not include WFS mechanisms here below GNIRS Mechanism Control Select configuration then APPLY to execute Filter Wheel 1 E LUE __ 4 Gr
37. this occurs the helium lines need to be topped off 6 6 5 Really Bad Weather For most bad weather the instrument can be left in the normal end of night state which consists of having the window cover closed and the detector deactivated This assumes that people will have some direct access to the instrument If the summit is evacuated the main concern is having the instrument warm up unnecessarily Probably the best way to ensure that this does not happen is to leave the cryocooler control switches in manual mode and on If the compressors are not operating the cryocoolers are safeguarded by the differential pressure switch but if the compressors are operating or start up the crycoolers will start up as well Note that there is some risk that one of the heads will freeze up see 6 6 4 above but there is little one can do to prevent that and cooling will still be better than with all heads off Note too that if the power is off for an extended period odds are the heads will warm up enough so that freezing is not an issue UPS power to the array controller should be turned off deactivate first of course If the instrument warms up significantly so that the bench is still above 85K when people return to the mountain cooling will be faster if the pre cool system is used Also if the instrument has warmed up at all even if not above 85K check the helium pressure in the pre cool system since it will have lost gas due to ther
38. wer is turned off on the driver to the affected mechanism the OT flag will be displayed on the mechanism window and an error is returned to the function moving the motor The hard limits are the same for both motors however the soft limits are slightly different When a linear mechanism detects a soft limit activation the OMS card ramps down the velocity and the calling function is returned an error The binary mechanism is a linear mechanism with just two states in and out When the binary mechanism moves to a position it drives until the soft limit switch is activated and then stops When datuming the binary mechanism drives to one of the limit switches determined by the gnirsConfig file backs off and then drives at a slower rate toward the switch The step position is set to 0 at the location where the soft limit is activated 6 2 3 Stall There are no encoders on the motors so there is no automatic way to detect a stall If you think there might have been a stall datum the affected motor If this doesn t function dropping the motor speed might allow it to move reliably Refer to Software Manual for instructions in modifying configuration files and loading them GNIRS Service amp Calibration Manual 94 Section 6 6 3 Cooling System Diagnostics This covers diagnosis of problems with the cooling system during normal operation The pre cool system is not used except for initial cool down and is not covered here The GNIRS primar
39. y cooling system consists of 4 Leybold RG5 100 cryocoolers connected to the optical bench by copper straps see section 8 4 for details The heads are connected together in pairs the straps are connected to the structure joining the pairs of coldheads referred to as the thermal busbar There are heater resistors mounted on the busbars which are used to add heat to the cooling system in order to maintain the internal structure at a constant temperature These resistors are controlled by a stand alone Omega controller in the components controller thermal enclosure The internal temperature needs to be maintained constant to within about 1 degree of 60K exact value may be changed and is normally stable to a few tenths of a degree The OIWFS detector is connected to the cold structure and maintained at a temperature of 78K using a separate controller The science detector is connected to the second stages of heads 1 and 2 and maintained at a temperature of 31K provisional by a temperature controller in the array controller enclosure Failures in the cooling system will manifest themselves as departures from the nominal temperatures usually in the form of values that are too high Bench temperatures that are out of range will set system health flags detector temperatures may or may not do so but will also produce excess dark current or excess noise especially on the science array Failure modes as possible diagnoses Bench temper
40. you can communicate with some computers but not others try re booting If that does not work try turning UPS power on and off Note that either course of action will require re initializing the system in question including datuming mechanisms and stabilizing detector temperature where appropriate Loss of communication between the GNAAC co adder and the DHS can require re booting both systems Note that the co adder does not control the detector directly so temperature control is maintained 6 6 4 Cryocooler Failures There are several possible failure modes of the cryocooler system Compressor failure If the compressors fail stop the supply pressure will drop quickly and the cryocooler heads will shut off automatically If the heads are off for more than a couple of minutes there is a risk that one or more will freeze up if the instrument is cold If this occurs when the heads are started again the outlet gas line will be colder than the inlet line on that head Under normal operation the outlet gas lines are always warmer than the input gas lines Frozen coldhead If a coldhead is frozen which can occur if it is stopped for too long when the instrument is cold the following procedures will probably fix the problem A quick fix is to turn off all the other heads and try running the problem head by itself running maximum gas flow through the head If the outlet line continues cold after a minute or so try the next step
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