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NAVAIR 17-20ST-134 TECHNICAL MANUAL 1 !;; INSTRUMENT CALIBRATION PROCEDURE DIGITAL THERMOM ETERS OMEGA ENGINEERING, INC. 650 SERIES, DSS-650 SERIES, AND DP465 SERIES THIS PUBLICATION SUPERSEDES NAVAIR 17-20ST-134 DATED 1 JUNE 1988 DISTRIBtmON STAll;MENTC DISTRIBUTION AUllfORIZEDTO U.S GOVERNMENT AGENCIESANDTHEIR CONTRACTORS TO PROTECT PUBLICATIONS REQUIRED FOR OFFICIAL USE OR FOR ADMINISTRATIVE OR OPERATIONAL PURPOSES ONLY. OTHER REQUESTS FOR THIS DOCUMENT SHALL BE REFERREDTO NAVY MEASUREMENT SCIENCE DIRECTORATE, NAVAL WARFARE ASSESSMENT DIVISION, P.O BOX 5000 CORONA. CA 91718-5000 PESTRUCTION NOTICE- FOR UNCLASSIFIED, LIMITED DOCUMENTS, DESTROY BY ANY METHOD THAT WILL PREVENT DISCLOSURE OF CONTENTS OR "RECONSTRUCTION OF THE DOCUMENT." PUBLISHED BY DIRECTION OF COMMANDER NAVAL AlR SYSTEMS COMMAND 1 OCTOBER 1995 NAVAIR 17-20ST-134 LIST OF EFFECTIVE PAGES lnsert latest changed pages; dispose of superseded pages in accordance with applicable regulations. NOTE: On a

changed page, the portion of the text affected by the latest change is indicated by a vertical line, or other change symbol, in the outer margin of the page. Page No. Change No.• Title 0 A 0 i 0 1 to 7 0 (8 blank) 0 9 0 (10 blank) 0 11 0 (12blank) 0 13 0 (14 blank) 0 IS 0 (16 blank) 0 A-l 0 Change Date Page No. Change No.• • Zero in this colwnn indicatcs an original page. A Change Date NAVAIR 17-20ST-l TABLE OF CONTENTS Page Section lntroduction and Description . 2 Equipment Requirements . 2 3 Preliminary Operations . 3 4 4.1 4.2 Calibration Process . Indicator Temperaturc Response Test . System Temperaturc Response Tests . 5 5

Navy Calibration Checklist . 9 7 A-l APPENDIX A: Representative TIs ILLUSTRATIONS Page Figurc TI Indicator Test Configuration . 5 TABLES Page Table Calibration Description NAVAIR 17-20ST-l SECTION 1 INTRODUCTION AND DESCRIPTION 1.1 This procedurc dcscribes thc calibration of thc Omcga Enginccring Inc 6S0 Scrics, DSs--6S0 Seri cs, and DP46S Scrics Digital Thcnnomctcrs, with or without accompanying thcnnocouplc(s). Instrumcnts that can be calibratcd using this proccdurc includc, but arc not limited to, thc modcls listcd in Appendix A. Tbc instrumcnt being calibratcd is rcfcrrcd to herein as thc TI (Test lnstrumcnt). 1.2 Ali commcnts conccming this procedurc should be dircctcd to Navy Mcasurcmcnt Scicncc Dircctoratc, Naval Warfarc Asscssmcnt Division, P.O Box S000, Corona, CA 91718-SOOO 1.3 This procedurc includcs tcsts of csscntial pcrfonnancc paramctcrs only Any

malfunction noticcd during calibration, whcthcr spccifically tested for or not, should be corrccted. Tablc 1. Calibration Dcscription TI Charactcristics Pcrfonnancc Spccifications Test Mcthod Indicator tcmpcraturc rcsponsc Rangc: spccified in Appendix A Tolcrancc: spccified in Appendix A A dircct voltagc is applicd through ice-point rcfcrcnccd tbcnnocouplc wircs to tbc TI to obtain a TI indication. Thc equivalcnt applied voltagc is tbcn comparcd to a tbcnnocouplc cmfvs. tcmpcraturc tablc. Systcm tcmpcraturc rcsponsc Rangc points: 32°F and 300°F Tolcrancc: spccificd in Appendix A lndication ofTI tcmpcraturc indicator and thcnnocouplc(s) is comparcd to tbc indication of a digital thcnnomctcr in ice-point and tcmpcraturc baths. Systcm rcsponsc tcsts arc requircd only if onc or morc tbcnnocouplcs arc submittcd with thc indicator. NAVAIR 17-20ST-134 SECTION 2 EQUIPMENT REQUIREMENTS NOTE Minimum usc specifications arc thc principal paramcters rcquircd for performance of thc

calibration, and arc included to assist in tbc sclcction of altcrnatc cquipmcnt, which may be uscd at thc discrction of thc using laboratory. Satisfactory performance of altcmatc itcrns shall be vcrificd prior to usc Ali applicablc cquipmcnt must bcar cvidcncc of currcnt calibration. Tbc instrwncnts utilizcd in this proccdurc wcrc sclcctcd írom thosc known to be availablc at Navy calibration facilitics, and thc listing by makc or modcl nurnber carrics no implication of prcfcrcncc, rccommcndation, or approval for usc by othcr agcncics. lt is rccognizcd that cquivalcnt cquipmcnt produccd by othcr manufacturcrs may be capablc of cqually satisfactory performance in this proccdurc. ltcm Calibration Equipmcnt 2.1 DC voltagc calibrator Rangc: -10 to +80 V Unccrtainty: ±(0.002% iv + 20 µ V) Flukc 332B or 332A 2.2 Voltagc dividcr Typc: Fixed ratio, rcsistivc Dividcr ratio: 1000 to 1 Ratio Unccrtainty: ±0.025% iv Input Rcsistancc: 10,000 ohrns Tcmperaturc cocfficicnt: 5 ppm/°C

Elcctr<rScicntific CA6042 2.3 Thcrmocouplc Typc: as rcquircd by thc TI, with copper cxtcnsion lcads Local supply 2.4 Tcmpcraturc bath Rangc: ambicnt to 300°F (ambicnt to 150°C) Hallikaincn 1132 2.5 Bath fluid Rangc: ambicnt to 300°F (ambicnt to 150°C) Dow Coming 2 I 0H 2.6 Thcrmomctcr holdcr Uscd with itcm 2.4 to hold itcm 2 7 Hallikaincn 1143A 2.7 Digital thcrmomctcr Rangc: 32 to 300°F Unccrtainty: ±0.6°F Doric DSIOOT5APRT34Al00 wirc 2 Minimum Usc Specifications NAVAIR 17-20ST-l Calibration Equipmcnt Minimum Use Specifications ltem NOTE ltems 2.4 through 27 arc requircd only ifthc TI is submittcd with thcnnocouplc(s) which must be calibrated togcthcr for TI systcm tcmperature responsc. 2.8 Icc-point bath, consisting of Valuc: 32.00°F (000°C) Unccrtainty: ±0.02°F (.±,OOl 0 C) 2.8 l Dcwar Flask: For usc in preparing an icc bath; capacity 600 to l OOO mb; dcpth 8 to 12 in. 2.82 1cc To makc slush for icc-point bath 2.83 Distillcd water To

makc slush for ice-point bath 2.9 Ice shavcr To crush ice for slush Fishcr Scicntific 8-495 2.10 Thcnnocouplc convcrsion tablcs For convcrting tcmperature to cquivalcnt thennocouplc EMF NBS Monograph 125 Local supply SECTION 3 PRELIMINARY OPERATIONS 3.1 Ensure that all powcr switchcs arc set to off, and set all auxiliary cquipmcnt controls as ncccssary to avoid damagc to thc cquipmcnt and so that dangcrous voltagcs will not be prescnt on output tcnninals whcn thc powcr switchcs arc turncd on. 3.2 Conncct thc DC voltagc calibrator (item 21) to an appropriatc powcr sourcc Sct thc calibrator POWER switch to STDBY /RESET and allow onc hour for warm-up. NOTE Thc TI docs not rcquire a warm up. (DP465 Serics rcquires a l O min. warm up) NAVAIR 17-20ST-l34 3.3 Preparc an ice-point bath (item 28) in the Dewar flask NOTE The Dewar flask, the shaved or crushed ice and the distilled water must be clean and free írom all impurities. Fill the Dewar flask with shaved or crushed ice

and add distilled water to make a slush. Use only enough water to obtain good contact with the thennocouple wires, (item 2.3) but not so much as to float the ice As the ice melts, siphon offthe excess water and add more ice. 3.4 If a checklist is not provided for the TI, use an existing checklist as a guide, and select four equally-spaced calibration points over the TI range span, including the minimum and maximwn values. lfthe TI is submitted with one or more thennocouples, the TI indicator-thennocouple system must also be tested at the ice-point and at l 50°C or 302°F. Record the applicable values in the FUNCTION TESTED column on the checklist. Using NBS Monograph 125 (item 210), record equivalent EMF values in the NOMINAL column. 3.5 lf the TI is not provided with a thennocouple, proceed directly to subsection 41 If one of more thennocouple(s) arc submitted, preparc for TI indicator-thennocouple system calibration as follows: 3.5 l Open the overflow valve on the temperature bath

(item 24) Ensure that a container is provided to catch any overflow. 3.52 Ensure that the bath is filled with Dow Coming 210H silicone oil (item 25) to the overflow valve NOTE The liquid levei in the bath should be maintained at the point of overflow during the TI system calibration. 3.53 Mount the thennometer holder (item 26) in the bath as required Secure the digital thennometer (item 27) PRT probe in the thennometer holder. 3.54 Ensure that the TI tbennocouple can be mounted in the holder or adjacent to it in close proximity to tbe PRT probe, but do not install tbe tbennocouple in tbe batb at this time. 3.55 Set the temperature bath power switch to ON; set the bath controls to 302°F 3.56 Connect the digital tbennometer and PRT probe to an appropriate power source, set tbe power switch to ON, and allow the thennomcter to wann up for l 5 minutes. 3.6 If a thennocouplc probe is coMected to tbc TI indicator, T/C INPUT tenninals, note the location ofthc thcnnocouplc leads and

disconnect tbc leads. 4 NAVAIR 17-20ST-l SECTION 4 CALIBRATION PROCESS NOTE Unless otberwise specified, verify tbc results of each test and take corrective action whenevcr tbc test rcquirement is not mct, before proceeding. 4.1 INDICATOR TEMPERATURE RESPONSE TEST 4.11 Connect tbc equipmcnt as shown in Figure 1, using tbc appropriatc tbermocouplc wires and copper cxtension lcads (item 2.3) Rcfer to Appendix A when selecting tbc tbermocouplc wire 2.3 2.3 THERMOCOUPLE COPPER EXTENSION LEADS WIRE 1 DCVOLTAGE CALIBRATOR + - o--~- -e 0--~- -e 2.2 VOLTAGE DIVIDER Hl 1N LO LO OUT :J- r r TI - - . - rrr (REAR) -, Hl .J ICEBATH . + TIC 0 - INPUT Figure l. TI lndicator Test Configuration NOTES Carc must be cxercised when connecting tbc tbennocouplc wires and copper cxtension leads to ensure correct TI rcsponse and polarity. Iftbe TI is a 650 series model, connect tbc higher potential wire to tbc TI indicator T/C INPUT plus ( +) tenninal and tbc lower potential

wire to tbc minus (-) tcrminal. If tbe TI is a DSS--650 series modcl, cnsure that tbc same convention is followed, and that tbc No. 1 tcrminals arc used For voltage indication rcquiring minus (-) millivolts from tbc voltagc dividcr (itcm 2.2) OUT terminals, connect the dividcr Hl and LO 1N banana plugs directly to tbc calibrator - and + OUTPUT terminaJs, respectively, instead of tbe connections shown in Figure 1. Care must be talcen to prevent the thermocouple-copper wirc junctions from contacting one another or to allow the junctions to be surrounded by pure water, as may occur at the bottom of the flask. A significant temperature error can be created if the above precautions arc not observed. Thermocouple and copper wire connections should be coated with paraffin or placed in a test tube to prevent electrical conductivity in the bath. 4.12 Connect the TI POWER Hl and LO terminals at the rear to an appropriate power source, observing the correct polarity; set the TI ON-OFF power

switch to ON. 4.13 Set the TI °CtF Scaling Switch to obtain a °C or °F indication; as required If the TI is a DSS-650 series model, ensure that the Terminal Selector Rotary Switch is set to l. 4.14 Set the DC voltage calibrator POWER switch to OPR/ON and the VOLTAGE RANGE switch to the appropriate setting. CAUTION DO NOT EXCEED 100 VOLTS OR DAMAGE TO THE VOLTAGE DIVIDER MAY OCCUR. 4.15 Perform the following steps at each calibration point on the checklist: 4.15 I Set the calibrator controls to obtain an exact TI indication, in °F, at the calibration point NOTE Tbc equivalent mi Ili volt value to tbc TI indication is listed in tbc NOMINAL colurnn of the checklist for reference. Tbc millivolt value, multiplied by 1OOO, is indicated in volts, witbout a + or - sign, on the calibrator display. 4.152 Verify that the calibrator indicates within tbc TI tolerance limits, expressed in volts Refer to the second note under step 4.11 regarding connections for minus (-) NOMINAL settings

NOTE Reset the TI 0 CtF Scaling Switch for a °C or °F indication, as necessary, to test tbc TI in tbc altemate temperature units. 4.16 If tbc TI is a DSS-650 series model, perfonn steps 4151 and 4152 at one calibration point for each remaining TI terminal connection to be tested, reconnecting the tbcrmocouple wires, as required. 4.1 7 lf tbc TI indicator is submitted for calibration without a thermocouple, attach a SPECIAL CALIBRATION LABEUTAG indicating that the TI indicator only was calibrated. Ifno other measurements arc to be made, set the TI and calibrator POWER switches to OFF, disconnect and secure the equipment. 4.18 lf onc or morc thcnnocouplcs arc submitted with tbc NAVAIR 17-20ST-l indicator, set tbc calibrator POWER switch to OFF, disconncct tbc test setup and procccd to scction 4.2 to pcrfonn TI systan tests, maintaining tbc ice-point bath for furthcr usc. 4.2 SYSTEM TEMPERATURE RESPONSE TESTS 4.21 Conncct tbc First TI Tbcrmocouplc to tbc TI indicator,

observing corrcct polarity 4.22 Ensw-c that tbc TI ON-OFF powcr switch is set to ON and that tbc °C or °F indication, as rcquircd 4.23 Carcfully immcrsc tbc digital tbcnnomctcr PRT and tbc TI tbcnnocouplc probc in tbc icc-point batb Rcfcr to tbe Notc undcr paragraph 3.3 and tbc tbird Notc under step 41 l on tbc propcr usc and maintcnancc of tbc batb and possiblc sources of tcmpcraturc dcviations. 4.24 Ensw-c that tbc digital tbcnnomctcr indicatcs witb tbc tolcrancc limits on tbc PRT Rcport of Calibration NOTE Adjust tbc digital tbcnnomctcr to indicatc 32.00°F or 000°C, as applicablc, and if ncccssary 4.25 Allow sufficicnt timc for tcmpcraturc stabilization, as displayed on tbc TI indicator Vcrify that tbc TI indicatcd tbe icc point witbin tbc tolcrancc limits on tbc chccklist. 4.26 Sct tbc TI °CfF Scaling Switch to tbc altcmatc tcmpcraturc unit, if rcquircd Vcrify that tbc TI indicatcs tbc icc point witbin tbc tolcrancc limits listcd. 4.27 Rcmovc tbc TI probc and digital

tbcrmomctcr PRT from tbc ice-point batb and allow tbcm to dry Carry them to tbe tcmpcraturc bath prcparcd for use in paragraph 3.5 4.28 Install tbc TI probc in tbc tcmpcraturc batb, as close to tbc PRT as fcasiblc Providc adcquatc support for tbc TI and digital tbcrmomctcr indicators, wcll away from tbc tcmpcraturc batb fluid 4.29 Allow sufficicnt timc for tcmpcraturc stabilization, as displayed on tbc TI indicator 4.210 Vcrify that tbc TI indicatcs within tbc tolcrancc limits listcd 4.211 Sct tbc TI °CfF Scaling Switch to a °C or °F indication, as rcquircd Vcrify that tbc TI indicatcs within tbc tolcraoce limits listcd. 4.212 Disconncct tbc TI probc from tbc indicator 4.213 Pcrfonn stcps 421, 423, and 425 through 4212 for cach rcmaining tbcnnocouplc probc submittcd witb tbe TI indicator for calibration. 4.214 lf no otbcr mcasw-cmcnts arc to be pcrfonncd, set all applicablc powcr switchcs to OFF, disconncct and sccure tbe cquipmcnt. (8 blank NAVAIR 17-20ST-l CAUBRATION

CHECKLIST TEST INST (S) PROC.NO Omega Enginecring, Inc. DP465KFDDSS02 Digital Thermometer NA 17-20ST-134 MFG. MS:.t~IIR PROCEDURE STEP SER. NO MODEL i y,41 I.JF~ FUNCTION TESTED NOMINAL FIRSTRUN SECONDRUN OUT OF TOL CAUBRATION TOLERANCES (2) (3) (4) (S) (6) (7) NO. (1) ck() NA lce-pt. bath prepared - ck() NA 3.5 Temp. bath prepared - ck() NA 4.1 Indicator Temperaturc Response 3.1 TI Inspection 3.3 #1 rest (OF) (mV) (V) (V) 337 -5.965 5.957 to 5.973 " 608 13.039 13.016 to 13.062 " 1544 34.909 34.886 to 34.931 " 2502 54.875 54.855 to 54.895 4.1S2 . " " " " " " " " " " " " . " " " " " " " " " 4.16 #2 " #3 " #4 " #5 . . " #6 " #7 " #8 " #9 " #10 " . 4.2 System Temperaturc Response ~ ~ 4.24 Adj. sut thermometer -

ck() (OF) (OF) 4.25 TI indication, 32°F 32 4.210 TI indication, 302°F 302 32.00°F NA (OF) 27 to 37 ±5 of sut. value Page 1 of 1 NAVAIR 17-20ST-l APPENDIX A REPRESENTATIVE TIS TIs which may be calibratcd using this proccdurc inlcudc, but arc not limited to, tbc following: Modcl Manufacturcr DS~5~TF-X Or iega Enginccring, Inc. T/C Typc Systcm Accuracy Rangc Indicator TIC T -238° to +752° ±l.9°F ±2%ivor ±l.5°F or ±0,75%iv• 65~TC Omcga Enginccring, Inc. T -150° to +400oc ±l.3oc ±2% ivor ±0,8°C or ±0,75%iv• 65~TF Omcga Enginccring Inc. T -238° to +752°F ±l.9°F ±2% ivor ±l.5°F or ±0,75% iv• DP465KFDDSS02 Omcga Enginccring K -337° -337° to to 2502°F 32°F ±0,7°F 32° to 2502°F ±4°F or ±2.0%, iv ,±4°F or ±0,75%iv whichcvcr is largcr • ±2% iv applics to tbc -150° to - 75°F or -101° to -59°C tempcraturc rangc: ±l .5°F applics to tbc - 75° to +200°F rangc; ±08°C applics to tbc

-59° to +93°C rangc; ±0. 75% iv applics to tbc 200° to 700°F or 93° to 371 °C rangc A 6.0 CAUBRATION 6.1 CAUBRATION OF V REF COLD-JUNCTION COMPENSATION AND FULL SCALE OARD Your model DP465 was calibrated at the factory with a precislon vottaoe source. Frequent calibration is not necessary due to the stability and intemal accuracy of the meter. When verification of calibration is necessary, the following procedure can be used. The linearization algorithms use the millivolt and cold-junction values plus the S1 jumper configuration to determine tne appropriate temperature display. Thua the millivolt and cold-junction displays are sufficient to detennine the calibration of the meter. To expedite the calibration check, a 4PST switch can be connected to the S1 A, C, E. and G positions of the pin torest located behind the front lens The meter will be unharmed if the operational modes are changed while it is operating. Results will be obtained more quickly if the digital

filtering is dlsabled. (See Sectlon 5.4) The V ref (rneter intemal voltage reference), is initially factory set to a value whlch results in a minimum temperature coefficient. ie, V ref versus ambient temperature This value is not the same tor all meters. lf the voltage reference must be replaced, retum the meter to the fadory. The V ref potentlometer (R20) Is sealed after lf this seal is broken, the accuracy of V ref is adiustment at the factory. questionable. the )ly. len the Potentiometer R21, the cold-jundion reütrence adjustment, is also factory set and sealed. Proper operation can be checked, however, by simply conflguring the meter tor CJ temperature display (Sectlon 5.1) and comparing the CJ temperature with the actual temperature of the terminal b!ock. Note that the temperature of the block must be known with an accuracy commensurate with the Model DP465 specifications. Full scale adjustment is controlled by potentiometer R11, locatad behind the lens (Figure 1-1), and is

front panel accessible. Adjustment can be made by conflguring the Model DP465 as a millivoltmeter lsee Section 5.1) Verify that the unit indiades : 0.00 mV with shorted inputs (TB1-5 and TB1-6) Then apply + 80005 mV to TB1-6, referenced to Analog Grouna (T81-5), and then adjust R11 tor a reading of + 80.00/8001 mV The 1/2 count is obtained when the display altemates between + 80.00 and + 8001 mV lf S4A is in place (Normai Position). approximately 50 nA wiU be flowing into the signal Input terminal: therefore the input resistance of the calibratlon source can offset the reading. 13 Calibrating the mater tor plus full scale should automatically insure calibration tor minus full scale; however, minus full scale can be checked to verify proper operation of the meter. ln this case, although -1999 mV is the most negative display value lt is more convenient to check the meter at -19.90 mV, which will avoid a possible underscale condition. lf Digltal Filtering is OFF (S3), recovery trom

underscale will appear to be instantaneous, i.e, as soon as the input voltage is in range lhe display will indicate in-range operation. lf Digital Rltering is ON, recovery will take longer because the digltal filtering is not automatically disengaged while the meter is in the overrange condltion. Note Ihat tor positive inputs, overrange does not occur in the mV mode until the disp&ay anentpts to exceed 99.99 or until the overrange condition causes intemal opendion of the anaJog section of the meter to cease, whichever oc:curs at a lower value. The meter cannot display mV values more negative than -1999 bec:ause the g-segment (center segment) ot the leading display diglt Is used to indicate minus. 6.2 CAUBRATION VERIFICATION USING THERMOCOUPLES 1 1 The tollowing procedure can be used to verify the calibration of the Model DP465 using T/Cs. 1. Connect test cables as shown in.Figure 6-1 2. Appty power and allow meter to warm up tor ten minutes. 3. Apply zero volts from the

Calibrated Voltage Source and verify readout of :!: O-C or 32°F. 4. Verify that the Model DP465 is operating within specification per the lntemational PracticaJ Temperature Scale, IPTS-68, as publlshed in the NIST Monograph 125 Thennocouple Tables il8ued March 1974 (or DIN 43710), by applying the appropriate voltage to the input Note that this method only raquires that the simulated measure junction temperature. The ice bath wiU zero the copper - T/C junc:tions tor the copper wires which are ccnnec:ted to the Calibrated Voltage Source: however, the cold junction c:omi,ensation detector cl the Model DP465 must flrst be calibrated so the meter will property compensate tor the T/C junctions at the meter barrler block. For accurate results. T/C wires which have a known accuracy should be used 14 6.3 1 1 ~ :on tor 3flltiOn value, lS9ible 318 will }8, the TB1 illtake ! meter J1 0 1 -- MAIN BOARD A ntil the ntemal i lower ecause ndicate THERMOCOUPLE WIRES URCE COPPER

WIRES 0P-165 1WIST TOGETHER AND SOLDER HERE :,f ~ )81 l8 O"C the NIST Ftgure 6-1 Ica Bath Callbration Setup 710), by 6.3 CONFORMllY VERIFICATION AFTER CAUBRATION >endUre. ,lch ara junr etar ~.11 iccurate 1 Even if the mater is not property calibratad, the conformity can be verified tor the indicated CJ temperature and millivolls dispiayed by the meter, then determine the temperature from the appropriate NIST (or DIN) table. The example below is for the J T/C, °C, configuration with the meter lndicating CJ • 23.6°C and 4109 mV (mV display). Note that in this procedure, only a stable millivolt source is required; neither T/C wires nor a separate milllvoltmeter is required. Thls conformity verification dernonStrates that. for given net MJ (measure junction) CJ vottaoe and CJ ternperature meter display vaJues, the oorrec:t MJ temperature result will be obtained when the meter is switched to the appropriate T/C configuration (using S1). 15 Millivolts displa yed

by meter: 41.09 Cold jundi on temperature displayed. "C: 23.6 NIST value tor 23.S°C: 1.2098 mV NIST value tor 750.2"C: 42.29 60 NIST value tor CJ = 23.6, MJ = 7502: 41.0862 mV (use linear interpolations of NIST values) switched to the J T/C mode. The expected meter display value Is 750°C when of one degree in this case (J T/C). Note that the meter display has a resolution the cold Junction value will cause in e chang Noise in the milliv olt source or a variations. the confonnity. This time the T The following is anoth er example of how to check of 0.1° will be used The object configuration, which has a display resolution tor values obtained from the NIST 1s to determine if the meter will displa y 390.3"C table. r:c STEP 1 1. 2. 3. MODE CJ MV T T/C DISPLAY 23.6"C 19.3311934 mV 390.3"C NIST VALUE 934.9 ,N 19335.9 ,N 20270.8 14V first configured to read CJ temperature in ln tne above example, the Model DP465 wa olation betwe en the values

tor 23 and "C. A value of 236"C was disptayed Unear interp 14V. Ukewise, 3903"C yields 202708 24C in the NIST table tor the T T/C yields 934.9 meter configuration was then changed which gives a net value of 19335.9 ,N The to obtain a displa y of 19.3311934 mV ted adjus to mV and a stable mlllivolt sourc e was This would be the vottage expected tor (altemating between 19.33 and 1934 mV) shoul d then yield a displa y of 390.3"C "perte cr T T/Cs. Changing the mode to T T/C value since, ina reallstic situation. a After step 3, it is advisable to rache ck the CJ could occur durin g the time interval change of 0.1"C (or more) ambie nt temperature be made more efficient by providing required tor the procedure. The proce dure can a SPST switch conne cted to S3A. a 4PST switch conne cted to the pin-torest, plus meter case.) When the SPST (See 5.3 tor an altemative whlch avoid s removing the there by disab ling the DP465 e. sourc switch is on, it simulates an extem

al serial data "v digital filtering. 16