IET Labs 1986 Omnical Page 1 User And Service Manual Download

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PRECISION INSTRUMENTS FOR TEST AND MEASUREMENT

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Email: [email protected]

TEL: (516) 334-5959 • FAX: (516) 334-5988

www.ietlabs.com

IET LABS, INC.

1986

Omnical

Sound-Level Calibrator

User and Service Manual

Visit www.ietlabs.com for manual revision updates

1986 Instruction Manual Dec. 2018

Summary of Contents for 1986 Omnical

Page 1: ...l info ietlabs com TEL 516 334 5959 FAX 516 334 5988 www ietlabs com IET LABS INC 1986 Omnical Sound Level Calibrator User and Service Manual Copyright 2018 IET Labs Inc Visit www ietlabs com for manu...

Page 2: ...Email info ietlabs com TEL 516 334 5959 FAX 516 334 5988 www ietlabs com IET LABS INC...

Page 3: ...ed at no charge when returned to IET Changes in this product not approved by IET or application of voltages or currents greater than those allowed by the specifications shall void this warranty IET sh...

Page 4: ...ve 2002 96 EC This product complies with the WEEE Directive 2002 96 EC marking requirements The affixed label indicates that you must not discard this electrical electronic product in domestic househo...

Page 5: ...lowed BEFORE APPLYING POWER Verify that all safety precautions are taken Make all connections to the instrument before applying power Note the instrument s external markings described under Safety Sym...

Page 6: ...iv 1986 This page is intentionally left blank...

Page 7: ...n 3 1 Initial Inspection and Setup 5 3 2 Dial Setting 5 3 3 Environmental Conditions 5 3 4 Storage 5 Chapter 4 Maintenance 4 1 Maintainability and Reliability 6 4 2 Preventive Maintenance 6 4 3 Verifi...

Page 8: ...vi 1986 Condensed Operation This page is intentionally left blank...

Page 9: ...only measured b Set instrument under test LEVEL RANGE to measure high on scale for LEVEL set in step a FAST or SLOW response WEIGHTING as desired normally A WEIGHTING c Read level on instrument under...

Page 10: ...Table 2 7 of manual RMS Accuracy Crest Factor Capacity Test a Set instrument under test LEVEL RANGE as desired 100 dB maximum upper limit FAST or SLOW response C or FLAT WEIGHTING b On 1986 set VARIA...

Page 11: ...nse Microphones GR 1961 9611 or 9602 none 0 3 1 0 3 5 1 in electret GR 1962 9611 or 9602 1987 7061 0 1 0 4 1 8 1 2 in electret B K 4131 45 1 in condenser 5855 6920 0 3 1 2 3 5 O ring B K 4133 65 1 2 i...

Page 12: ...4 1986 This page is intentionally left blank...

Page 13: ...ne The 1986 is also supplied with an adaptor that mates with GenRad 1 2 in electret condenser microphones An optional adaptor set is available to accommodate the 3 8 in microphone used on the GR 1954...

Page 14: ...6 1986 Introduction...

Page 15: ...25 Hz Selects frequency of calibrated output level in CALIBRATED SPL mode disable in other 5 VARIABLE SPL modes 6 LEVEL 6 position rotary switch POWER OFF 114 104 94 84 74 dB Disconnects instrument fr...

Page 16: ...actor test crest factor Calibrator generates a series of pulses with a crest factor of times 3 9 SPL ADJUST 1 turn continuous potentiometer Used in conjunction with LEVEL control allows continuously v...

Page 17: ...9 1986 Introduction This page is intentionally left blank...

Page 18: ...10 1986 Introduction This page is intentionally left blank...

Page 19: ...by ANSI S1 4 1971 IEC Publications 123 1961 179 1973 and 179A 1973 and Consolidated Revision of IEC Publications 123 and 179 In tone burst modes output can be either continuous SET FAST SLOW or SET C...

Page 20: ...ptable range Microphone coupling Transducer cavity accom modates following 1 in microphones GenRad 1961 electret condenser GenRad 1971 ceramic Accessories supplied Coupler adaptor to accommo date GR 1...

Page 21: ...ones the Western Electric 640AA or equivalent micro phone and the Tokyo Riko MR103 microphone The 1986 is also supplied with an adaptor that mates with GR 1 2 in electret condenser microphones An opti...

Page 22: ...TOP SECTION SHOWN SEPARATELY STORED 3 4 1 EXTENDED Figure 1 1 Controls indicators and connectors NOTE 1986 shown upright for illustrative purpose only proper position is resting on feet...

Page 23: ...Recess in housing Contains 9 V alkaline Compartment access obtained via battery that provides hinged cover instrument power 5 FREQUENCY 6 position rotary 4k 2k 1k Selects frequency of cal i switch 50...

Page 24: ...tr Calibrator generates con tinuous 2 kHz tone at LEVEL selected adjust able with SPL ADJUST used to set reference for crest factor tests crest factor Calibrator generates continuous series of 2 kHz t...

Page 25: ...ction manual not shown and optional carrying case is not part of package Table 1 2 GR 19S6 9700 PACKAGE Description Omnical Sound Level Calibrator instrument only Adaptor for 1 2 in Microphone Battery...

Page 26: ...consists of 1 6 Box for adaptors below GR 1954 Microphone Adaptor GR 1954 Microphone Adaptor Cap 0 Ring forB K Type 4131 32 1 in microphone Adaptor forB K Type 4133 34 1 2 in microphone Adaptor forB...

Page 27: ...new alkaline battery will provide approximately 8 h of continuous operation To install the battery proceed as follows a Orient the 1986 so that the battery compartment is accessible see Figure 2 1 b...

Page 28: ...osion at its terminals To remove the battery for replacement or storage proceed as follows a Orient the 1986 to make the battery compartment accessible see Figure 2 1 b Loosen the captive thumbscrew t...

Page 29: ...hould be replaced Three accessory desiccant kits P N 5863 3002 in air tight packages are supplied with the instrument each kit contains 1 indicator and 2 papers The desiccant papers are made from a si...

Page 30: ...CAUTION When storing the transducer be careful not to pinch the extension cable in the retaining fingers 2 7 MICROPHONE ADAPTORS 2 7 1 General The transducer cavity of the 1986 will accommodate the fo...

Page 31: ...groove all the way around the inside of the cavity To remove the 0 ring slide a small screwdriver down 1 of the 3 grooves in the cavity until it is behind the 0 ring and then pry it out GR 1987 7076 M...

Page 32: ...PL switch to fast Repeated 1 000 Hz tone bursts should be audible These tone bursts have 200 ms pulse durations and are used for measuring the FAST rise response of a sound level meter The bursts are...

Page 33: ...evel meter or analyzer using the 1986 They are Sensitivity Frequency Weighting Linearity and Tracking of Indicator and LEVEL RANGE Control Dynamic Characteristics RMS Accuracy Crest Factor Capacity Th...

Page 34: ...libration indication this can be especially significant at the lower levels of the 1986 a The 1986 offers a choice of 5 calibrated output levels Select the level closest to the level that is to be use...

Page 35: ...they are required g An example of a microphone correction follows Conditions of Measurement FREQUENCY 1 kHz Microphone Type G R 1962 9611 1 2 in electret flat perpendicular Correction from Table A of...

Page 36: ...pending on the correction required for a particular microphone Some microphones require no correction Refer to Table A of the Condensed Operating Instructions for correction information d Select in tu...

Page 37: ...0 2k 113 9 11 2 9 114 9 11 0 9 116 9 111 9 11 5 9 109 9 11 7 9 4 k 113 3 11 2 3 114 3 108 8 118 8 110 3 116 3 107 8 118 8 IECt Type 3 107 8 111 8 110 7 114 7 111 7 115 7 112 0 116 0 110 9 116 9 108 3...

Page 38: ...ol linearity per IEC specifications LEVEL RANGE control accuracy per ANSI and IEC specifications Indicator The indicator of an instrument can be a meter or digital display and in many cases an instrum...

Page 39: ...trol to the reference range t if the reference range is not known choose the 100 dB full scale range The instrument may be set to FAST or SLOW response and FLAT Cor A weighting b Set the 1986 as follo...

Page 40: ...ed The LEVEL RANGE control on the instrument under test is then switched to another range and the 1986 LEVEL control is varied correspondingly Ideally the reading of the indicator should not change as...

Page 41: ...stant is 1 s The standards are very specific in detailing how a sound measuring instrument will be checked to verify its operation in both of these modes A steady state reference signal of 1 kHz must...

Page 42: ...RMS Accuracy In practice many signals to be measured are impulsive and contain much of their energy in peaks A sound measuring instrument must be designed to indicate the rms value of such signals and...

Page 43: ...lected in step a VARIABLE SPL set crest fctr c Set the SPL ADJUST control on the 1986 for a reference indication 2 dB below full scale on the instrument under test this will be either 108 98 88 or 78...

Page 44: ...for its 1 kHz band Then select the other 5 FREQUENCY positions on the 1986 one at a time while at the same time selecting the 5 corresponding octave filter bands on the instrument under test This allo...

Page 45: ...38 7 250 18 0 14 9 Note Reference 18 0 14 9 40 0 38 7 500 40 0 38 7 18 0 14 9 Note Reference 18 0 14 9 40 0 38 7 1 k 40 0 38 7 18 0 14 9 Note Reference 18 0 14 9 40 0 38 7 2k 40 0 38 7 18 0 14 9 Note...

Page 46: ...solidated Revision Standard tMaximum allowable reading above reference level when VARIABLE SPL control is changed from fast or slow to set fast slow 2 9 9 Decay Time The rate at which the reading on a...

Page 47: ...cking the decay time of an impulse detector a On the instrument under test set the LEVEL RANGE control to a range having an upper limit between 80 dB and 120 dB The instrument should be set to IMPULSE...

Page 48: ......

Page 49: ...ndom or perpendicular sound incidence with respect to the plane of the microphone s diaphragm Since free field incidence is not simulated within the small dimensioned cavity of the 1986 where its tran...

Page 50: ...9 GRID ON 5855 6920 8 K 4133 65 1 2 in 1987 2050 0 0 0 3 0 8 condenser 8 K 4135 1 4 in 1987 2060 0 0 0 0 0 2 condenser Measurement Cond iti ons Atmospheric Pressure 760 mm 30 in of Hg Temperature 20 C...

Page 51: ...para 2 12 2 This allows a combined correction factor that accounts for both of these effects Table 2 12 lists these combined correction factors for various microphones If a microphone being calibrate...

Page 52: ...Response Microphones GRID ON Western Electric 640AA 4160 1 in condensery Tokyo Riko MR103 1 in condenser 8 K 4132 1 in condenser t 8 K 4134 1 2 in condenser B K 4136 1 4 in condenser None None 5855 6...

Page 53: ...by cavity and microphone volume considerations Typically an application for its use would be the calibration or check of a sound level meter electrically i e excluding the microphone One example wher...

Page 54: ...monitor wh ich has a 5 dB exchange rate The calibration number for the 1954 9730 monitor is 0 78 A cross check of the above calibration can be made by comparing the results using the 1986 calibrator w...

Page 55: ...ed for reference when performing the sensitivity test described in para 2 9 2 3 2 2 ANSI Excerpt The following excerpt is taken from para 6 2 6 2 1 6 2 2 6 2 3 6 2 4 6 2 5 and 6 2 6 of the ANSI Standa...

Page 56: ...For a Type 3 instrument the acoustical or electrical sensitivity check signal and method for checking shall be specified by the manufacturer 3 3 FREQUENCY WEIGHTING CHARACTERISTICS 3 3 1 General The e...

Page 57: ...Figure 2 4 Table 3 2 TOLERANCES FOR LEVELS IN TABLE 3 1 t Nominal Tolerances in dB per Meter Type Frequency Hz Type O t Type 1 Type 2 Type 3 125 0 7 1 0 1 5 2 0 250 0 7 1 0 1 5 2 0 500 0 7 1 0 1 5 2...

Page 58: ...he indicator and LEVEL RANGE control 3 4 2 ANSI Excerpt for Indicator Linearity The following excerpt is from para 5 1 5 1 1 5 1 2 and 5 1 3 of the ANSI Standard S1 4 1971 it provides specifications f...

Page 59: ...ange for a particular instrument is specified by the manufacturer and usually refers to the top 15 to 20 dB of the indicator s range Table 3 6 TOLERANCE ON DIFFERENTIAL LEVEL LINEARITY IN THE FREQUENC...

Page 60: ...0 0 3 0 5 0 1 1 20 12 500 0 5 1 Taken from Tab le V I in the IEC Consol idated Revision 3 4 6 IEC Excerpt for Combined Linearity of Indicator and LEVEL RANGE Control The following excerpt is from para...

Page 61: ...of an instrument 5 3 Fast Dynamic Characteristic The sound level meter shall possess the following dynamic characteristics which may be identified as UFASTn 5 3 1 If a pulse of sinusoidal signal havin...

Page 62: ...fied in Table 3 9 and to a suddenly applied signal or step in signal level with overshoot as specified in Table 3 11 When the suddenly applied signal is turned off the meter indicator shall decay by 1...

Page 63: ...of a continuous sequence of rectangular pulses and for a sequence of tone bursts to that for a reference sine wave signal It is recommended that the sine wave signal have a frequency of 2kHz The rect...

Page 64: ...nd thereafter held constant The maximum readings shall not exceed the final steady reading by more than the amounts given in Table 3 11 when the test signal has a frequency between 100Hz and 8kHz When...

Page 65: ...lifier output current source amplifier transducer driver The digital circuitry provides tone burst timing signals for the fast slow and crest factor modes as follows fast mode slow mode crest factor m...

Page 66: ...he voltage at the center of the 2 resistors R37 and R38 is then 0 V neglecting approximately 0 15 to 0 2 V hystenesis effects of R59 wh ich is the ground voltage When U12 5 becomes more positive than...

Page 67: ...element resistance of controi FET 01 Resistor R14 and 01 in series allows a possible gain change from times 1 0 to times 3 1 which is sufficient to overcome the gain loss in the Wein bridge circuit an...

Page 68: ...inversion necessary to give the not continuous logic control on U13D The gain shift amplifier U12A is a self feedback amplifier that shifts the nominal level to give the proper gain for the various o...

Page 69: ...the calibrator Components C10 and R51 prevent oscillation of the amplifier due to the transducer s inductive load at high fre quencies The transducer s inductive load impedance at 1 kHz is SOU 5 The t...

Page 70: ...y to 1 kHz or 2kHz in certain modes In the fast and slow modes the tone burst frequency is locked into 1 kHz in the crest factor mode the tone burst frequency is locked into 2kHz Although these are th...

Page 71: ...FAST AND SLOW TIMING RST I CTHE U M OF A AND HI G t J SLOW PULSE OCCURS 1 OUT OF 10 S FAST PUl E OCCURS 1 OUT OF 2 S RESET I H RESET 100 co H Cl U2 10Ht co 10 1 FAST OR SlOW U4 10 LOW ON RESET tF SI...

Page 72: ...he analog output in the fast mode Note that U6B is selected by either the fast or slow mode so that the background level control gate U6D responds to the output level control signal The background lev...

Page 73: ...RATION 5 5 ms R CRESTFACTOR J2e 5 3 0151 I ON IL oN 5 5 CF GAIN SHIFT 5757 d6 20 LOG CF 20 LOG 2 J v 0 0 9 586 3 0 03 6 5757 d6 REQUIRED FROM SET CREST FCTR TO CREST FACTOR RESET I 1 0 5 1 ms 38th PUL...

Page 74: ...at is also the data input of USA While the Q of U78 is going low the same clock cycle at CLOCK is transferring the signal at to the Q output of USA This sets up AND gate U5C for the next positive cycl...

Page 75: ...und the frame of any line powered equipment test instruments lamps drills soldering irons etc directly to earth ground and be sure they have rubber feet or other means of insulation from the work surf...

Page 76: ...st office for a Returned Material number Use of this number in correspondence and a tag tied to the instrument will ensure proper handling and identification After the initial warranty period please a...

Page 77: ...he transducer cavity of the 1986 under test e Place this transducer adaptor assembly over the microphone of the 1982 and select the following on the 1986 FREQUENCY LEVEL VARIABLE SPL 1 kHz 114 dB CALI...

Page 78: ...rn the SPL ADJUST fully counterclockwise and again note the 1982 indi cation The difference between the 2 readings should be at least 11 0 dB I Set the SPL ADJUST control for an indication of 116 0 dB...

Page 79: ...ted 180 and then plugged back into the board to set the 1986 for the non interlock mode of operation When the dot on the top of the J1 connector is adjacent with the dot on the board the jumper is in...

Page 80: ...Time Total of Tone of Tone Period Burst Burst s s s 16 0 4 0 76 0 8 0 2 0 38 0 4 0 1 0 19 0 2 01 o 5ot 9 5t 1 0 0 25t 4 75 0 5 0 125t 2 375 off Time represents a 20 dB drop from the On time t Denotes...

Page 81: ...er 5 6 TESTS AND CALIBRATIONS CAUTION The following procedu r es are intended for an experienced technician The following procedures should be performed after an instrument has been repaired or when t...

Page 82: ...ERNAL BATTERY HERE FREOUENCY INTER LOCK DOT ON CONNECTOR IS ADJACENT TO DOT ON BOARD FOR FREQUENCY INTERLOCK MODE REVERSE THIS ORIENTATION FOR FREQUENCY NON INTERLOCK MODE Figure 5 2 Circuit board P N...

Page 83: ...w 5 General purpose ac dc 100 mA range Data Precision 3400 Ballantine 323 VTVM a Make the setup shown in Figure 5 3 The power supply can be connected directly to the circuit board at WT1 and WT2 if t...

Page 84: ...for checking the level and distortion of the 1986 AC OUTPUT a Connect the DVM set to AC to the 1986 AC OUTPUT connector using the GR 1560 P77 Cable b Set the 1986 as follows FREQUENCY LEVEL VARIABLE...

Page 85: ...should be from 1 32 0 20 V to 0 420 0 06 V Failure to meet the above voltages indicates either a defective transducer or 1986 circuit In order to determine ifthe transducer is defective replace the tr...

Page 86: ...le 5 6 FREQUENCY CHECK READINGS 1986 Frequency Setting Hz 125 250 500 1 000 2 000 4 000 1192 Frequency Indication Hz 122 1 129 7 243 7 258 7 486 2 516 2 970 1 030 1 935 2 054 3 862 4 100 d Set the 198...

Page 87: ...NGE 1 kHz 114 dB CALIBRATED SPL SET LEVEL SET LEVEL 100 d Adjust the HP 334A SENSITIVITY vern1er control for a reference reading of 6 0 dB on its meter e Change the 1986 VAR lAB LE SPL control to set...

Page 88: ...at 104 dB 5 6 7 Timing Functions a Make the setup shown in Figure 5 4 in the following sequence refer to Figure 5 2 INPUT B 100 pF REAR I L JV A BNC 1 r TP19 47 kQ GR 1986 1192 OMNICAL INPUT A FRONT _...

Page 89: ...14 200 1 2 000 5 slow 114 1 500 1 10 000 5 crest factor 104 10 110 1 500 2 counter s trigger level must be properly set to obtain correct reading 5 6 8 Crest Factor Burst level a Connect the DVM to TP...

Page 90: ...are normally glyptolled in place at the time of original calibration and they should not be tampered with unless a full calibration facility exists 5 7 TROUBLE ANALYSIS When a malfunction is suspecte...

Page 91: ...etwork L Inductor M Meter References MK Microphone ASA Y32 16 and M IL STD 167 6 1 MECHANICAL PARTS Figures 6 1 6 2 and 6 3 show locations of mechanical parts on the GR 1986 adjacent tables Iist descr...

Page 92: ...14 12 11 10 9 8 Figure 6 1 Mechanical parts on front panel and transducer assembly 6 2...

Page 93: ...er Electromagnetic 1986 1020 24655 1986 1020 1 aluminum diaphragm converts electrical signal to acoustical output 8 Gasket Styrene butadiene 1986 7045 24655 1986 7045 Housing elastomer provides moistu...

Page 94: ...13 10 9 8 Figure 6 2 Mechanical parts on side and rear panels 6 4...

Page 95: ...655 1986 7015 compresses and locates battery in battery case 6 Pad Foam adhesive cushions 1986 7030 24655 1986 7030 cover against battery 7 Pin Battery Metal inserts into hinge 1986 S010 24655 1986 S0...

Page 96: ...55 1986 7070 Desiccant observation of desiccant indicator 2 Frame Styrene butadiene 1987 7085 24655 1987 7085 Window elastomer provides moisture and dust control 3 Screw Cover 0 112 40 thread 1987 600...

Page 97: ...e Li J 6A tSr ND AHPLI t l l ll lll t ul 1 AMPt n wiD i f I I A N C Nrr 4 Cf h rc 0 tl I I 1 Ac ex r vr __ UI N So Jtt AH iO 14 j 0 i lt IL J AL 41 I f A lSI _ o c C NroJVt V S H lf CT s _ e 0 e St J...

Page 98: ...CAUTION THE FOLLOWING COMPONENTS REQUIRE SPECIAL HANDLING FOR STATIC PROTECT ION REFER TO ESPM 247 I ll 1 21 Q l 01 BorTOM VI EW Figure 5 6 3 FOR MtNC FOF OTIOM VI...

Page 99: ...I r1 c r 1 1 JD 7 cc _L________ u c _I__ I v I ____ _ 3 I I 0 5 r _ _ _ 0 J z t r 1T10 I J 6 6 Analog schematic diagram Figure 6 9 n D f _ o i vt 1 I _ L...

Page 100: ...RACKING TEST 1986 I Instrument Under Test I Level Meter Readinu OK Digital Reading OK ldB dB dB Instrument Under Test 1986 I Level Mater Reading OK Digital Reading OK Fuii Sc ala Level on dB dB B 7 In...

Page 101: ...UF 2 OPCT 10V MTP 120UF 20PCT IOV 150D225 X90ZOA2 8131 M0 0 651 IOSM 0831082Z 50D0271 J 150D1 06 X002082 8131 MO 50 651 1 0411 8131 10 50 1 51 1 OSM 1500187X0006R2 150D187X0006R2 083l082l5D006 80J 810...

Page 102: ...It 2 00 l2S l It r L 1401 1 V r 11 J W I TPH r L lJ 0 VS 6 8 9 1C 2 BAS E D A F IS o1 n t n IN NCOI t V L Tt OCII R J1 nn QI i Jt ICIE n n 1 TTTTTTTTT l_ _ __ ______ ___ ___ ___ _________j 6 7 Digita...

Page 103: ...mm of mercury to in of mercury proceed as follows a Find the barometric pressure value in mm of mercury on the right hand scale b Obtain the corresponding value in mbar from the same scale c Move to...

Page 104: ...New Hampshire 141 Memphis Tennessee 81 Miami Florida 21 Milwaukee Wisconsin 593 Minneapolis Minnesota 865 Mobile Alabama 598 Moncton N B 2717 Montgomery Alabama 45 Montreal P Q 1204 Nashville Tenness...

Page 105: ...Netherlands 50 16 Ankara Turkey 640 2250 Arhens Greece 92 300 Belgrade Yugoslav1a 138 450 Berlin Germany 35 115 Bombay lnd1a 8 25 Brussels Belgium 58 190 Buenos Aires Argcmina 14 45 Cairo F gypt 30 9...

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