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1. CODE BINARY POSITION x678 1234 5678 SWITCH sw 2 SW 3 sw3 Example Code 3FE CODE 3 F c BINARY ou un 1100 POSITION x678 1234 5678 SWITCH sw2 sw3 sw3 3 decodes to unit 3 F decodes to parallel printer with graph and text C decodes to 0A and 00 print ending and 2400 baud The baud rate is not used in parallel TROUBLESHOOTING Blank display Press ON OFF key If still blank change battery Unit will not start when battery changed Try again Disconnect printer from unit and reconnect battery Return for service Unit reads low Check that internal switches are in proper position Reset unit Change microphone and recalibrate unit Unit reads high Check position of internal switches Reset unit Unit is erratic Change microphone INTERPRETING RESULTS When the M 27 is set up for OSHA compliance and for most other settings the following are in general true The HTL Lavsg is less than the LTL and Lavg is less than Leq The HTL Dose and TWA are less than the LTL Dose and TWA If Run Time is less than eight hours TWA is less than Lavg if Run Time is more than eight hours TWA is greater than Lavg The SEL is greater than Leq The 3 dB Dose is greater than the LTL Dose if Leq is greater than the Criterion Level it is less than the LTL Dose if the Leq is less than the Criterion Level The above may2. SE TABLE OF CONTENTS e o InNnS tructions INTRO DUCTION E 3 M 27 SIMPLIFIED OPERATING INSTRUCTIONG AAA 5 Control KY Se aissciviosaicvnrecsvmr toons Eege Ee EEGENEN ER 5 E a a ae ee EE ee A Sound Level Meter KEY Sissi cscamwencererese wer veswonsecuerieutx See eueiereed 6 DOSIMGCIO E 6 UU 7 Event EN 7 Procedure to Accumulate Event Data ENEE 7 Setting th CIO CU enee Eeer NEE 8 Recording the Calibration LOVE sis ccenssecicevesassivevenendchursniowesicvvensGuaesaodserexcexers 8 Using a Printer E 9 Dumping RaW Data EN 11 Changing Printer Parameters EEN 11 SPECIFICATIONS wisisssipninscutussgnnshsiesinnataeriesiunitaduniansaenmuadaiansnaeepeanitamdadaianiataslesiondunoentuauusten 11 GENERAL DESCRIPTION bad ccniviccsniescanvine Eelere 12 PRINCIPLES OF OPERATION visited sidexivaw tuiau pacea ea ana aa e aaa ia 13 E 13 Weighting Characteristes oiisvcicicics icvenntinnsnansicnswerwiecntunencaacenteusssncacpeunswerwenwats 13 a Microcomputer Modes nenna 14 Formulas and Desen geehe Age Eege Eege Eege 16 TESTING AND CALIBRATION cssisiisastcetanviensateninaceacsensaeeinasaweabuind teatevteunsatsabecnedeeementes 17 N 0 S E Battery eebe 17 Battery Replacement nssaannsunnnnnunnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn ennnen nnnnn nnmnnn nnna 17 LOG G N G Microphone Replacement EEN 18 Calibration and Maintenance un 18 DOSI METER Daily Calibatl Olea deser crated oreciceceuraiecuaceneneerduntiutosenemenneeupeeusessrsiseaesnenent 18 Al
3. 800 245 0779 Office hours are from 7 AM to 6 PM Central Standard Time Monday through Friday For service or recalibration outside the U S A please contact your local Quest Dealer or fax Quest U S A at 1 262 567 4047
4. O h O h OS OS O h Ov eh d 1 6 1 4 es 3 6 _ E 12 3 5 2 2 Sample Statistical Distributions DOSE STATISTICAL DISTRIBUTION 80dB 61 1 23 2 55 2 32 4 35 11 02 85dB 3 37 6 34 5 59 4 17 3 572 23 07 90dB 4 23 3 19 1 50 35 002 09 22 61 is the percent dose accumulated at 80 dB 1 23 is the percent at 81 dB etc The percent dose statistical distribution is accumulated without a threshold Of course the dose calculations in the summary exclude any dose accumulated below the threshold The graph is similar to the TIME graph If the internal TEXT or GRAPH switch is off that portion will not be printed 3 dB Only Systems The previous examples illustrated the M 27 when used with two different exchange rates It can be used as a 3 dB only system with three different histograms one with no threshold and two with thresholds It will also print four statistical distributions two with a Time constant and two without If the M 27 is used for community or 3 dB industrial monitoring the printout will contain much more information than would a data logger with a single printout NOTE If the criterion level is set to 85 dB then the dose reading can be easily converted to Pascal squared hours For a 3 dB system with a 85 dB criterion level a 100 dose is equal to I Pascal squared hour To calculate the exposure in Pascal squared hours divide the dose by 100 Dump
5. high on the shoulder and away from the neck as far as practical see Figure 6 If the noise is directional it is generally the best practice to place the microphone near the ear which receives the most noise exposure If the M 27 is to be used as a hand held instrument the microphone should be mounted on the MB 1 microphone bracket see Figure 7 It may either be clipped to the bracket or the clip removed and the microphone screwed to the bracket The bracket is then attached to the belt clip on the back of the instrument If desired the complete unit can be mounted on a tripod see Figure 8 The microphone should be pointed upward forming approximately a 70 degree angle with the noise source It should not be pointed at the noise source Use with Windscreen To prevent wind from blowing across the microphone and causing erroneous measurement of sound level the model WS 5 Windscreen should be used It is recommended that the windscreen be used at all times Insert the microphone in the windscreen and gently pull it over the Velcro strip Using a Printer The M 27 can print out to Centronics compatible parallel or serial printers at 300 600 1200 or 2400 baud see Figure 9 It can also send various line feed and carriage return combinations to accommodate different printers It is necessary that the printer and M 27 agree on protocol and that the proper cable be selected for a printout Serial Printers Check the printer manual to s
6. me n 82aqa8 d ss zm ee em wm mm eee KK t e 9408 Se 7608 TEE EE EE 7608 n aa m zm mm 7808 _ 5508 cB Op Op Om D ow Oh 5 lt lt lt 9 2 3 9 t 31 5 EE EE EE 30 7 LEE 7 5 L 6 9 d er zm mm e 3 3 Th oh Oh Oh oh Oh O h OS 1 1 2 3 1 2 1 9 ze zm d 7 1 0 on Figure 2 Sample Printout Dumping Raw Data The data stored in the unit may be transferred to a computer or printer for reprocessing This data is useful only with additional computer programs Consult Quest for programs CODE Press key until CPU is displayed HL3 PRINT Prints raw data to computer ON Stops printout OFF Changing Printer Parameters Internal switch 3 contains the printer parameters This switch may be changed without erasing stored data This allows switching printers or computers without destroying data See Printer Setup page 32 NOTE Internal switches 1 and 2 are read only when the unit is RESET SPECIFICATIONS Standards ANSI S1 4 1983 type 2 ANSI S1 25 1978 IEC 651 type 2 UL Intrinsic Safety Class I Group C D Class II Group E F Class III Detector True RMS 63 dB pulse range Display Liquid crystal display Range 01 to 2999 Annunciators HTL LTL 3 dB LOBAT RUN and PAUSE Printout RS 232 serial at 300 600 1200 or 2400 baud or Centronics parallel Connector 20 pin shrouded header Microphone 8 mm PZT ceramic 36 inch cable field replace
7. 00 00 00 00 00 60aB 00 00 00 00 05 6508 6 ss 12 DZ se D 1 73 700B 3 76 1 51 92 1 70 1 28 750B 2 09 74 51 40 63 80dB 5 51 16 29 4 86 3 41 3 30 8508 13 28 2 83 2 02 6 91 2 99 90a0B 4 69 15 2 27 91 1 77 op Op 3 45 3 06 03 03 64 10008 3 86 2 25 1 07 60 01 1050B8 00 00 31 38 00 1100B 00 00 00 00 00 DOSE STATISTICAL DISTRIBUTION 500B 00 00 00 00 00 5508 00 00 00 00 00 60aB 00 00 00 00 00 6508 se 00 s ee M D ee HES 700B 00 00 00 00 00 7508 00 00 00 00 00 800B 07 26 09 08 10 SOp SA 14 13 56 30 90aB 21 02 46 23 57 950B 1 41 1 58 02 02 _ 66 10008 5 03 3 70 2 21 1 56 03 1050B8 HU 02 2 03 3 16 5 1100B8 06 00 10 04 00 Figure 15 ih ee ee ee E E SS e kb St 4 Eh Ha dk p Hoeven eure e zb E O O h O h 5 e zm 9 2 3 9 oo on ae an on ce an hy om ae oop 21 5 KEE EE EE 30 7 lt ek y em om zm 6 O o ao an 8 3 C O Ov O h O O h O O h REN K e 2 3 41 2 9 A 7 1 0 Ok Or O h O wm 2 1 i as e ae 9 1 4 3 e zo zm bes ez bz zm zs bz 33 3 oa ae ee oar eee zember 28 0 eg 6 7 7 2 d Z 6 Ov
8. 4 Press CODE HL3 until CAL is displayed Press SOUND LEVEL If the level is correct press PAUSE RESET until CAL is displayed 5 If the reading is off slightly insert a small screwdriver in the hole above CAL and slowly turn the CAL screw until the display reads correctly Press PAUSE RESET until CAL is displayed 6 The M 27 is now calibrated and ready for use 7 Ifa calibrator is used at any frequency other than 1000 Hz then the proper correction for that frequency weighting must be made see Figure 4 Altitude Corrections The effects of atmospheric pressure on the M 27 are negligible However calibrator sound levels are affected by pressure and corrections must be made For the Quest Calibrator the correction is 1 dB for each 2000 feet above sea level OPERATING PROCEDURE As a Personal Noise Dosimeter 1 If display is blank press ON OFF to turn unit on 2 Clear the M 27 memory by pressing and holding down the PAUSE RESET key until it counts down from P 5 to P 0 and 3 If LOBAT is displayed replace the battery and continue 4 Check the calibration of the unit see Calibration and Maintenance 5 Check CODE to see if correct 10 DI g 0 Perpendicular 3 Incidence S 0 e Random gt _5 SCH _ or 70 Incidence w D 10 20 50 100 500 1K 2K 5K 7K 10K Frequency Hz Figure 5 Model 1845 Microphone Response Perpendicular and Random Incidence 6 Attach t
9. Data If the CODE HL3 is cycled until the display shows CPU raw data may be dumped to a computer when PRINT is pressed Each line contains an address and 16 bytes of memory starting at that address see Figure 16 See Memory Map section for a description of the data General When printing the M 27 remembers which keys have been pressed 0000 7F 20 00 FF FO BS 00 00 F4 30 00 00 00 00 00 og 0010 SE SF 2B 86 SF F3 8E AA 2C 9B ED AO 60 OE E3 FE 0020 AD 99 85 50 6B 16 19 00 1D 02 04 03 01 13 00 00 0030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 FF 00 0040 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0050 00 00 00 00 00 op oo op 00 00 00 00 00 00 00 00 0060 00 00 13 4B OB E OB E OB E OB E OB 7F EO 54 0070 00 19 98 13 06 12 E7 OB FF OB 7F E2 18 00 08 Di 0080 00 BF F4 77 77 00 01 71 00 00 00 00 OA 83 46 02 0090 01 01 05 00 00 A3 AO 00 00 00 00 00 00 SF 00 02 OOAO 09 BG OD OC 00 00 01 O2 00 OE 00 OF 00 O2 01 00 O0OBO op 00 96 C5 00 00 4A op AZ AO 00 48 18 00 00 00 OOCO FF 10 11 12 03 OF OE 00 FF 00 00 00 00 00 00 00 OODO DO CF GA FF 00 FF OF 00 00 00 00 43 FA 16 E 00 O0EO 00 00 00 00 DE 04 40 D7 00 CO 25 04 AE D7 04 40 OOFO SA 2A F1 81 C7 07 46 81 1F 01 C6 00 FC 1E 01 81 0100 00 00 1A SA SE 49 GO 00 00 00 4D 9B 47 00 00 00 0110 00 3F A9 D 00 00 00 00 00 00 00 00 00 00 00 op 0120 00 00 00 00 00 00 00 00 00 00 00 00 12 B1 10 1D 0130 40 00 00 00 33 4D 8D 40 00 00 00 2A 84 AE 00 20 Figure 16 Sample of Raw Data and prints only
10. For best results connect the M 27 to a printer only when printing data INTERNAL SWITCHES The M 27 is set at the factory to the current OSHA requirements unless otherwise specified When the CODE key is pressed the display shows a coded display of the current internal switch settings As an example if the display is a 4 digit display such as 10EE then the unit is set to a criterion level of 90 dB for 8 hours an exchange rate of 5 dB a high threshold level of 90 dB a low threshold level of 80 dB 115 dB upper limit level A frequency weighting the 50 dB to 146 dB range a SLOW time constant and a 12 hour clock If the display is a 3 digit code then the first number is the unit identification number The next two digits are the printer setup The printer setup may be changed at any time without erasing data The other switches are only read when the unit is reset Some examples of common switch settings and codes are as follows OSHA Compliance and Hearing Conservation A Weighting 90 dB High Parallel Printer 50 146 dB Range Threshold Text and Graph 115 dB Upper Limit 80 dB Low Threshold LF and CR Slow Time Constant 12 Hour Clock 600 Baud 90 dB Criterion Unit Unit 1 5 dB Exchange Rate Switch 1 Switch 2 Switch 3 Ist CODE LOEE 2nd CODE IFE Department of Defense A Weighting 80 dB High Serial Printer 50 146 dB Range Threshold Text and Graph 140 Upper Limit No Low Threshold LF and CR Slow Time Constant 12 Hour C
11. Printer Output The serial printer output is RS 232 C compatible It sends data in ASCII code at 300 600 1200 or 2400 Baud The data is sent asynchronously The Data Set Ready line is checked before sending a character Each character consists of 11 bits made up of a start bit 8 ASCII character bits and 2 stop bits Each line is terminated by a line feed and or carriage return characters Printer Switch Setup The internal switches must be set to agree with the printer Switch 3 controls the printer see Internal Switch Settings Positions 1 and 2 should normally be off Positions 3 and 4 are normally on graph and text Positions 5 and 6 control last 2 characters line Many printers work if both are on Positions 7 and 8 control baud rate 7 on and 8 on 300 baud 7 on and 8 off 600 baud 7 off and 8 on 1200 baud 7 off and 8 off 2400 baud Parallel Printer Setup When set to parallel the M 27 is compatible with most Centronic compatible printers The M 27 sets up 8 data lines if the Busy line is not high it sends a Strobe pulse If the Busy line stays high for more than a few seconds the M 27 will cancel the printout Printer Switch Setup See Internal Switch Settings Positions 1 and 2 are normally ON for parallel printers Positions 3 and 4 are normally ON graph and text Positions 5 and 6 control the last 2 characters line Most printers work with both ON Positions 7 and 8 are undefined for parallel Compu
12. reset or the PAUSE key is pressed Wait until the sound level has stabilized before entering the run mode Always remember to press RUN Press PAUSE before pressing PRINT If in the run mode the data printed at the beginning of the printout will not agree with the data at the end Considerations of Measurement and Accuracy An integrating meter such as the M 27 Noise Dosimeter can integrate all continuous intermittent and impulsive sound levels within the range of the instrument This avoids many of the potential errors created by attempting to read and correctly interpolate sound level meter readings in fluctuating sound fields However it is important to use the M 27 correctly and to understand its limits true of any instru ment to achieve its maximum accuracy Microphone location generally has the greatest effect on the accuracy of any noise measuring instrument The correct placement of the M 27 microphone has been discussed under Effects of Operator Presence Threshold discontinuity can cause notable differences in readings on various meters if the noise level is near the threshold Since the instrument assumes that noise even slightly below the threshold is absolute quiet that noise level is not accumulated into the results while a noise level just slightly higher is accumulated This is most noticeable in the readings of dose if the threshold is the same as the criterion level Peak noise levels greater than the range of the ins
13. that data As an example if HIST 5 has been pressed pressing PRINT will print out a heading a summary a 5 minute histogram and a statistical distribution If HTL is annunciated pressing HIST 10 will print a 10 minute histogram for the high threshold level only It is possible to change the printout while it is printing by pressing PAUSE other keys and PAUSE again Or it can be changed by just pressing another key Memory Map DUMP prints a memory dump of the M 27 s random access memory or RAM Consult the Quest factory if you need a complete description of each memory location Memory Location Memory Location Data 0000 000F MC6805 ports and timer 0010 003F Setup dose and time 0040 007F Stack 0080 00FF Scratch pad 0100 012F Current event 0130 01BF Print buffer Memory Location Data 0100 01CF 3 dB stat overflow address of stat store 0200 02BF 3 dB stat store 2 bytes level 02CO 02FF Threshold stat overflow 0300 03BF Threshold stat store 03CO 05BF 16 Events 03CO 1FFF 1 minute histogram The last location is the HTL for the first minute the next is the LTL and next is for 3 dB Each minute it repeats in blocks of 3 Editing Printout A complete printout of all the data stored in the M 27 may be more than 25 feet long and may be more than is needed If only the data for hearing conservation is required press CODE HL3 until the LTL annunciator is displayed Pressing PRINT will reduce the data by one half
14. zecken schecke 95dB 10 15 is the start time of the program 103 is the decibel level at 10 15 97 is the decibel level at 10 16 etc 00B THRESHOLD 1 MIN HISTOGRAM 06 15 Gd 87 OO OD ZO OO o1 95 09 25 02 90 74 08 30 oo 100 KN Op 28 OO OO 00 08 40 DO OO 86 Op 45 OO OO OO os 50 as OO OO 08 55 OO OO TS Oo OO 65 bk a4 09 05 64 op oo 09 10 00 OO OO 09 15 00 op op 09 20 00 00 00 09 25 00 op op 800B THRESHOLO 1 MIN HISTOGRAM os 15 op 88 84 08 20 op 91 95 08 25 02 90 73 08 30 99 100 92 08 35 80 80 OO 08 40 85 85 90 08 45 87 87 87 08 50 90 8 amp 1 82 09 55 89 63 x Ay G og OO 70 70 26 oa 05 85 85 85 09 10 85 a2 HO 09 45 80 81 80 09g 20 OO OO OO 09 25 OO OO OO 308 EXCHANGE 1 MIN HISTOGRAM op 15 94 oo 84 09 20 OO 93 95 08 253 04 GK 83 08 30 EE EE 04 08 35 a1 BO OO 08 40 85 as 4 08 45 87 87 B8 os SO 3 84 82 08 553 RO 75 85 09 00 78 79 B8 9 05 85 84 a4 09 10 84 84 Si 09 15 81 82 81 09 20 00 00 oo OS 25 OO OO OO OO o OO CO Oo OD CO o CO o ad PO OO bh OO O oi A N Oo OC 00 OO OO OO D i 90 79 87 92 DO DA 84 82 85s BO DO 00 OO RATE D o gt fu Cal a 50B EXCHANGE RATE 00GB OOaB OP OOGB OOGB OOaGB 1O20B OOOp 760B B30B OOOp OOOp 00GB OOGB OOGB S508 EXCHANGE RATE ODOOp OOObP 920B B10B 820B amp 70B 0208 88dB 770B amp 70B amp 50B8 800B DOOp OOOp OOOp Bi OOOp OOOp 9208 8108 8308 8708 o20B SSaBb 8608 88aB
15. 13 13 22 100cB 3 56 3 02 71 1 00 01 10508 02 02 18 52 00 1100B 00 00 00 00 e 00 DOSE STATISTICAL DISTRIBUTION 50aB zs OO zs OO zs 00 00 00 5508 00 00 00 00 00 GOOp 00 00 00 00 600 65GB ss OO 00 00 00 00 7008 sz OI 03 01 ss 01 ss O2 750B ses D 02 00 01 00 80aB 06 68 23 15 07 8508 953 34 09 78 30 90GB sz 26 05 37 19 36 95086 ss 37 1 21 04 5 09 10008 141 78 1 73 47 76 01 1050B 02 02 24 79 00 11008 ss Of ss OI ss OI 02 02 RUN TIME 1 00 01 PAUSE 10 40 MIN LEVEL 67 108 UPPER LIMIT 11508 MIN TIME 08 50OH M UL 00 oO 800B THRESHOLD 30B EXCHANGE RATE LAVG lt lt 2 90 308 LEO sz zz M23 00B TWA ce eee em e e e 75 308 SEL 128 608 DOSE vn wm mm mm em zm 13 05 DOSE 25 30 enr DOSE 104 4 Bnr DOSE 202 3 8008 THRESHOLD 30B EXCHANGE RATE LAVG 93 308 L O zz zsm si 93 90B OOSE lt lt lt e 81 DOSE 1 25 enr OOSsSE 159 2 SEL e 115 506 S008 THRESHOLD 308 EXCHANGE RATE LAVG 93 908 LEQ 96 508 DOSE e enee ep ep pr 4 27 DOSE 11 17 onr DOSE 172 9 SEL lt lt 125 008 ees dee 259442 2 gt 92as8 Powe aegerreet eceoertece SdB a a aa a d ee o4 dB t bb be n CrAOD EE EE 720B
16. 79 dB 6 00 A4 1 66 207 9 49 6 15 1 07 1 42 1 78 2 14 Accuracy of Readings 6 30 9 1 19 1 49 1 8 6 45 73 HH 1 22 1 47 There is a tendency to overestimate the accuracy of digital readings In the M 27 some values T JU T 7 x 96 l 15 such as Lavg and TWA are computed to 0 1 dB The absolute accuracy of the reading is not 0 1 dB See Lg 2 s 90 S I SO specifications for accuracy and tolerances However the resolution of 0 1 dB is useful in determining the E y Kr eil 2 ay i Gei sample time required for a short term sample As an example if Lavg reading is increasing 2 dB every e a 0 i 0 n nu i second then additional sample time may be required If the Lavg reading remains stable within a few 0 1 8 15 13 17 99 26 dB s then the sample time may be long enough 8 30 op 34 13 52 8 45 38 EN 64 77 Hints and Good Practices 9 00 I 67 84 1 02 9 15 63 83 1 04 1 26 Gg 9 30 74 99 1 23 1 49 The M 27 is in the pause mode after the battery is replaced when 9 45 ap 114 1 42 1 71 10 00 96 1 28 1 6 1 93 10 15 1 07 1 43 1 78 2 15 10 30 1 18 1 56 1 96 2 36 10 45 1 28 Bi 2 13 2 56 11 00 1 38 1 83 2 29 2 76 11 15 1 48 1 96 2 45 2 96 11 30 1 57 2 09 2 61 3 15 11 45 1 66 2 21 2 07 3 33 12 00 1 76 2 33 2 92 3 52 12 30 1 93 2 57 3 21 3 87 13 00 2 1 2 8 S 1 2 13 30 2 27 LO 3 77 1 54 14 00 2 43 3 22 t 03 4 86 14 30 2 58 3 43 4 28 5 16 15 00 CC 62 1 53 5 46 15 30 2 87 3 8 1 77 5 74 16 00 3 01 4 5 6 02 it is turned on is
17. 84aB8 Bias 8 10B 00GB OOGB pr NOTE Op Op Figure 13 Sample Histogram Printouts wea ta nn at 4 9208 SE EE EE E 860B See hm Ke dbeseeebke zeen bere 940B e be zs bz bz zz bs zm 9408 7208 oe et He He KK dem 8208 sasegforoeseqee e 6 t G 40B wb bb db 7608 we HH ee tone 76a0B bz t 7808 e S508 es ze zc bss zs zs bs zz bz zs zz bz 9308 8808 bm zs zm ze e zm zm bz zm 4 0B lt a te HHH 9 40B at am ato i oe Ge 8208 oy ae ee oe oe on ew a on os me DOP ze e bb e e e E e e e e E e e GOeOH 86dB 820B ne a a a a d R S Mt Ep 820B ee po 8508 SS ePwrwrneage sana 8208 eae r a i 810B a zz bz zm zz bz zs zz bz zm 94 lt G086 e zm E zm ze zm ze db zm lt 4 90aqB e taa lt 4 lt 9808 zm sn zm zm zm Ab 96a08 e e ze bz nz zm bn en ze ze bz zm S508 ee 89aB e e zm bz ze ze zm br zm o bz zz ze bz zs zm 970B eee hemKcefesefoeres 88aBs SS eas 44 2 8708 a ma 8508 S5aB 8208 e Goon teece 4 8108 If the level is less than the threshold for part of the minute the average can be less than the threshold If no levels above the threshold level are measured the level is set to 00 dB The first in the graph is 50 dB and the next is 60 dB etc Each is 2 dB 105 dB is the average of the 5 levels combined with a 5 dB exchange rate Each line
18. CHANGE RATE SaGB CRI TER ION 90GB RANGE 5008 TIME CONSTANT SLOW WE IGHT UNO A EVENT 1 START TIME O0O8 21H M RUN TIME 02 27 PEAK LEVEL 125 60B MA Reese e eme a 96 00GB EVENT 2 2 START TIME OS 25H RUN TIME 11 PEAK LEVEL 138 708 000B THRESHOLD 1 MIN HISTOGRAM UN 1 T 2 END TIME 09 25H M MAX LEVEL 118 808 MAX TIME 08 15H M 900B THRESHOLD LAVG 87 80B TWA 72 808 DOSE 9 26 enr DOSE 74 0 LAVG oi 908 DOSE ka Snr OOSE 137 3 9008 THRESHOLD LAVG 93 308 DOSE 3 96 8nr DOSE 160 4 50B EXCHANGE RATE 08 15 ea a7 OO KA ODOoOp 08 20 OO 91 95 oo oocB os 25 102 90 74 90 92GB os 30 99 100 91 ais ODOOp 08 35 oo oo DO B4 ODOOp 08 40 OO OO 86 90 ODOOp 09 45 DO OO 00 100 10208 Op DO ee oo DO OO OOOp 08 55 oo oo 75 84 76aB 09 00 65 65 84 67 83aB 09 05 64 oo oo 57 ooaB 09 10 DO OO OO OO ODOOp 09 15 oo OO OO 0 ooaB 09 20 OO OO OO OO ooaB 90GB8 THRESHOLD 50B EXCHANGE RATE TIME STATISTICAL DISTRIBUTION 500B 00 zs 00 00 00 00 55086 ss 00 00 00 00 00 GOOp 00 00 00 00 00 6508 00 00 ss OO ss 21 32 7008 1 64 4 02 97 93 1 69 7508 1 43 1 23 40 62 31 8090B8 1 98 19 16 53 653 3 33 1 40 8508 13 65 4 85 1 14 8 20 2 81 90GB 2 23 38 2 24 1 02 1 67 9508 2 29 4 22
19. Off Off Off Off On On On On SWITCH 3 Position 1 Position 2 7 8 Exchange Rate Off Off 3 dB Off On 4dB On Off 5dB On On 6dB 1 2 Off Off Off Off On On On On Off Off Off Off On On On On 3 Off Off On On Off Off On On Off Off On On Off Off On On On 24 hour 6 7 Off Off On Off Off On On Busy On Parallel printer Off Data Set Ready Off Serial printer 4 HTL Off 70 On 70 Off 75 On 80 Off 85 On 90 Off 75 On 80 Off 85 On 90 Off 80 On 85 Off 90 On 85 Off 90 On 90 Off Unit 0 1 2 3 5 7 handshake Normally positions 1 and 2 are set the same dB dB dB dB dB dB dB dB dB dB dB dB dB dB dB dB 12 LTL none none none none none none 70 dB 70 dB 70 dB 70dB 75 dB 75 dB 75 dB 80 dB 80 dB 85 dB hour Position3 On Print Graphs Off No Graphs Position4 On Print Text Off No Text If 3 and 4 are both off Graphs will print Positions 5 6 2nd and Last print character in HEX On On 0A 0D LF CR Off On 0A 00 LF On Off 0D 0A CR LF Off Off 00 0D CR Positions 7 8 Baud Rate On On 300 baud On Off 600 baud Off On 1200 baud Off Off 2400 baud Setting Internal Switches The M 27 has over 15 million unique setup options The setup is determined by the position of the three 8 position switches located inside the battery compartment Externally the settin
20. Stop Mode If the ON OFF key has been depressed for 5 seconds the M 27 enters the stop mode In the stop mode the processor stops accumulating but does not erase data Power is removed from the analog circuitry and the display circuitry The oscillator is stopped Only a few microamps of current are drawn from the battery to maintain the microcomputer s memory and to power the ON OFF key When the ON OFF key is then pressed the computer returns to where it was before it was turned off except it will be in the pause mode Formulas and Definitions The M 27 uses the following formulas to calculate the accumulated data 100 e cae DOSE od SES gree al 3DOSE Si RTIME 9 L3 CRIT 3 01 d LAVG ER on f R gian OS CR rme TWA ER LOG f ee at LOG TC SLL SO LEQ 3 01 ron f RIME ge e LOG ams LOG ai e d LHIST ER vom deer cal me Ed EZE wl LMIN ER Loc K Sg ree DOGO wn o TIME 100 X STAT RTIME 16 DOSE 100 X STAT 2 ETARTE d TO 4 16 Where LS Sound level in dB with slow time constant if the sound level is greater than the threshold level and is if the level is less than the threshold level L3 Sound level in dB without slow time constant TC Criterion time in seconds or 28800 seconds RTIME Run time in seconds ER Exchange rate in dB CRIT Criterion level in dB HTL High threshold level LTL Low threshold level LHIST Level stored each minute for
21. The microphone is field replaceable To unscrew the microphone grip the knurled nut on the top of the dosimeter and gently turn it counterclockwise Do not twist or turn the cord or black strain relief Replace with new microphone and recalibrated unit Calibration and Maintenance The M 27 should maintain its accurate calibration for many months of use However to insure consistently accurate operation it is recommended that the unit be returned once a year for a complete checkout and calibration The calibration standards for the equipment in Quest s laboratory are traceable to the N LS T The M 27 should be checked each day before it is used It is recommended that one of the Quest calibrators be used with the proper 8 mm microphone adaptor Daily Calibration 1 Turn M 27 on and press any key If LOBAT is displayed the battery is low and should bechanged 2 Turn on the calibrator and check the battery indicator Replace the battery if required If the calibrator has multiple frequencies or levels set it to 1000 Hz Listen to see if the calibrator is producing a tone 3 Remove the windscreen from the microphone Carefully insert the microphone in the microphone adaptor and place the adaptor in the calibrator Make sure the microphone is inserted all the way in the adaptor and the adaptor rests flush on the inner rim of the calibrator Turn on the calibrator If the calibration is done at high altitudes see Altitude Corrections below
22. able Battery Single 9 volt alkaline 80 hour battery life Battery Indicator 8 hour battery life 1 week data retention Calibrator External calibrator Temperature 15 to 50 C operating 40 to 60 C storage battery removed Humidity 0 to 95 non condensing Magnetic Field Effects Negligible below 50 Oersteds at 50 to 60 Hz Size 5 x2 x 3 8 inches 140 x 70 x 40 mm Weight 14 ounces 400 grams Construction Cast aluminum housing with tamper water and dust resistant security cover GENERAL DESCRIPTION The microprocessor based M 27 Noise Logging Dosimeter can be used as a personal noise dosimeter an area monitor and as a noise survey instrument It can be used to check compliance with the requirement of the Occupational Safety and Health Administration OSHA or as a community or Department of Defense noise logging dosimeter The M 27 simultaneously monitors multiple noise functions for 3 separate dosimeters as well as sound peak and maximum levels and run pause upper limit and real or elapsed times It also stores displays and prints out data for 16 different events The readings can be taken at any time without destroying or resetting the data Even turning the unit off will not destroy the internal memory A water and dust resistant cover protects the unit from the elements and against tampering The unit is small enough to be placed in a shirt pocket or on a belt with the microphone clipped to t
23. ad 1CE 4 Press RUN Wait until a representative sample of the noise in the area has been accumulated 5 Press PAUSE RESET The display will show the next current event number Figure 7 Microphone Mounted Figure 8 M 27 Mounted on Bracket on Tripod 6 Move to the next area and repeat steps 4 and 5 7 When finished with survey or when 16 events are accumulated press ON OFF to exit EVENTS At any time even when accumulating data the current or any previous event data may be displayed Press EVENT key until the desired event is displayed Press any other key to display data for that event If the CODE HL3 key is pressed it will display the current time for the current event and the start time of previous events It will also cycle through HTL LTL and 3 dB To determine when a representative sample has been taken press Lavg Leq for the current event If the value does not change by more than a few tenths of a decibel over a few minutes the data should be valid for that area Effects of Operator s Presence Any object or surface can act as a reflector or absorber of sound An operator or person wearing the dosimeter is also a reflector of sound and affects the microphone performance The M 27 is designed to read correctly with the microphone in a random incidence sound field without the presence of reflecting objects The recommended placement of the microphone for personal noise monitoring is on the shirt collar
24. avg TWA will be greater than Lavg if time is greater than eight hours WORK The M 27 automatically computes the TWA of a worker if the unit is worn by the worker for a full i ersa aA e workday Even if the worker does not work exactly eight hours the TWA measurement will read the correct HR MIN 3 01dB 4dB 5dB 6 02dB TWA for that worker 0 30 12 04 up on 24 08 1 00 9 03 12 15 18 06 Lavg can be used with short term sampling to estimate the worker s TWA If the noise exposure 1 30 7 26 9 66 12 07 14 53 during the sample period is representative of the noise throughout the workday and the workday is eight 2 00 6 02 8 10 12 04 hours then the TWA for that worker is equal to the Lavg measured with the short term sample 2 30 5 05 6 71 8 39 10 1 3 00 4 25 5 66 7 07 8 51 Estimating TWA from Lavg A Ce Sar F die e SS e a t 15 2 74 3 65 4 56 5 49 A short term sample can be used to estimate worker exposure even if the workday is other than 4 30 2 49 3 32 1 15 4 99 eight hours by adding or subtracting a correction factor from the Lavg reading 4 45 2 26 3 3 76 4 52 5 00 2 04 2 71 3 39 4 08 As an example if a worker has a Lavg of 85 50 dB after a ten minute sample and the sample is v i l l be 2 43 9 03 3 z a representative of the noise throughout the workday and the workday at that position is 7 15 then from S g S 3 P 3 E e o an A 2 ag Table 4 under a 5 dB exchange rate find 71 dB and subtract it from 85 50 to compute a TWA of 84
25. d 1 dB statistical distributions Is housed in a secure dust proof case May be clipped on belt or shirt pocket Area Monitor Accumulates 40 hours of 1 minute histograms and statistical distributions May be tripod mounted Figure 1 M 27 Noise Logging Dosimeter Events Monitor Accumulates the following data for up to 16 separate events 3 separate integrated sound levels 3 separate noise doses 2 time weighted averages and a sound exposure level Peak level maximum level start time and run time The M 27 as an overall unit accumulates data for 3 separate dosimeters 3 separate 1 minute time histograms 2 separate percent time statistical distributions 2 separate percent dose distributions 16 separate events Sound levels peaks and maximum levels Run time pause time and elapsed or real time The unit displays Sound level peak level maximum level 2 integrated average levels An equivalent sound level 3 percent doses 2 time weighted averages A sound exposure level 16 separate events Run time pause time and upper limit time the time greater than preset level Elapsed or real time clock 12 or 24 hour Calibration level Code of 24 internal switch settings The unit prints out A heading Summary of accumulated data and setup parameters Up to 16 separate events 3 separate 1 3 5 or 10 minute time histograms 2 percent time statistical distributions 2 percent dose statistical distributions Raw
26. dB 2 8 97 1 13 832 paa LG 7 04 4 03 is the percent of run time at 50 dB 2 58 is the percent time at 51 dB etc Each is 10 starting at 0 Each is 2 900B THRESHOLD DOp EXCHANGE RATE A TIME STATISTICAL DISTRIBUTION SOdB Sec D I n D I 09 e HE zen 00 S5aB 00 Q00 00 lt 00 DA 60 0B 00 00 00 00 00 65GB ee O09 00 ms AE S 26 7008 64 4 02 zez Rf 93 1 69 50B STAS el erer 740 S SNA 800B ed 98 9 d 3 603 3 33 1 49 8506 13 69 8 863 41 44 8 29 2 8 7 90GB 2 23 38 2 824 1 02 1 67 9508 2 29 4 22 13 13 22 100GB 3 06 9 02 71 el EL 0 1 10508 a 02 02 see AB lt 352 oz 00 1100B 00 OI DD ene OD lt 00 h DOSE STATISTICAL DISTRIBUTION SOdaB at H ee 090 ees DI oe DES 00 5508 D I 9090 00 Q0 00 6008 S 00 SS OO 3 te eren eet 6508 00 00 00 en OD 00 7008 me O04 tz HS een HI se RT mM 02 75aB a 02 zs HE see DD 01 00 DOOp EO ae a Vee SC Ko 85daB oe Oe eee em OS es 78 se SEN 900B 28 08 37 19 36 9S5aB EZ ei i 04 20S 00 1000B 2jA 468 1 739 4 lt 76 ee O1 10548 O28 O27 224 Fs 900 1100B HI 041 e 04 02 02 30GB EXCHANGE RATE WW TIME STATISTICAL Ol STR BUTION 500dB 00 00 es OO 00 00 5508
27. data for computer storage and manipulations Includes editing capability to print out only required data The M 27 internal switches select Exchange rates of 3 4 5 or 6 dB Criterion levels of 80 84 85 or 90 dB 2 thresholds of none 70 75 80 85 or 90 dB 2 ranges of 35 126 or 50 146 dB A or C frequency weighting Fast or slow time constant Upper limits of 90 115 or 140 dB 12 or 24 hour clocks 8 different unit numbers Text graph or both printouts Serial or parallel printers Baud rates of 300 600 1200 or 2400 Line feed carriage return or both The above features packaged in a compact rugged hand size easy to use instrument make the QUEST M 27 Noise Logging Dosimeter the Ultimate dosimeter M 27 SIMPLIFIED OPERATING INSTRUCTIONS When using the unit gently press key until light click is felt Hold down until unit responds Generally this will be immediately unless the unit is calculating data such as sound level in which case it may take up to a second Control Keys RUN Starts or continues accumulating data Display shows run time Also used to start Events PAUSE Stops accumulation of data Display counts down from RESET P 5 to P 1 If key is not released in 5 seconds unit will reset and old data will be lost Key is also used to reset Clock Calibrator Events and pause the Printout ON If OFF press to turn on If ON hold key down display OFF counts down from 0 5 to 0 1 and the
28. e or an Event In 30 dB range lowest peak measurable is 78 dB in 50 dB range the lowest measurable is 98 dB MAX The Maximum Level in decibels after the filter and Slow LEVEL or Fast time constant circuit Dosimeter Keys L AVG The average integrated sound level in decibels for the LEQ HTL High Threshold Level LTL Low Threshold Level or the equivalent level for 3 dB It is the accumulated sound averaged during the Run Time DOSE The accumulated Dose in percent for HTL LTL or 3 dB TWA Time Weighted Average in decibels for HTL and LTL SEL It is the accumulated sound averaged over 8 hours For 3 dB it is the Sound Exposure Level of the accumulated sound averaged over second Time Keys RUN The total time the unit was running and accumulating TIME data If the total time is less than 30 minutes the co lon will blink if the key is held down and the time shown is in minutes and seconds If the colon stays on the time shown is in hours and minutes PAUSE The time the unit was on but not accumulating data TIME The colon blinks as in Run Time U L The time exposure was above the Upper Limit The TIME colon blinks as in Run Time Event Keys The event feature accumulates Lavg Leq Dose TWA SEL for 3 dosimeters Peak Level Max Level Run Time and Start Time for up to 15 different events Each time a key is pressed in the Event mode the display will show the event number and the data EVENT Enters Events and cycles th
29. et printer to serial and desired baud rate If switches in the printer are changed make sure the printer has accepted these changes This may require turning the printer off for a few seconds and turning back on Check printer interconnections to determine proper cable including male and female pins on the connector Set the internal switches in the M 27 to agree with the printer It is not necessary to reset the M 27 when printer switches are changed Figure 9 M 27 Connected to 80 Column Printer Parallel Printers Check printer manual to set up printer If switches are changed it may be necessary to reset the printer Check interconnecting cable to assure it is the proper cable Set the internal switches in the M 27 to agree with the printer It is not necessary to reset the M 27 if switches are changed Connections to Printer 1 Make sure printer is set up to agree with M 27 2 Connect printer cable to printer 3 Turn on printer 5 Connect printer cable to M 27 Cable goes toward top of M 27 with red strip in middle of unit After data is accumulated a printer is connected to the M 27 and the stored data is printed see Figure 9 The printer may be used while the M 27 is still gathering data to obtain intermediate results No data is lost in either unit until the unit is reset All the data may be printed or only selected data if desired It is possible to change the printout in the middle to obtain for ins
30. g of these switches can be determined by pressing the CODE key on the front panel and decoding the display by using Figure 17 SWITCH 1 SWITCH 2 SWITCH 3 Figure 17 Internal Switches If a 4 digit code and either HTL LTL or 3 dB is displayed The first digit is a 1 for a 12 hour clock and a 2 if it is set to 24 hours The second determines the weighting range upper limit and the time constant The third determines the criterion and exchange rate The last digit determines the two thresholds As an example if the display reads 10EE Find the 1 code in the first digit column in Table 2 The clock is 12 hours The 0 means the time constant of weighting is A the range is 50 146 the upper limit is 115 dB and the time constant is Slow The first E means the criterion is 90 dB and the exchange rate is 5 dB The second E means the high threshold level HTL is 90 dB and the low threshold level LTL is 80 dB If a 3 digit code is displayed with HTL LTL and 3 dB The first digit is the unit identification number The second digit determines serial or parallel printers and if text graph or both will be printed The last digit determines the printer line feed and carriage return characters and the baud rate If the code is 53E 5 is the unit identification number for this unit It can be set to any number from 0 to 7 The number is for user use only and does not affect the operation of the M 27 The 3 means it i
31. h When the clock is set to the current time it will record the actual time for Events and Histograms CODE Press until the display includes a colon The display HL3 is in hours and minutes To set clock press 0 and num bers for the current time The time will move in from the right The clock is not set until PAUSE RESET is pressed PAUSE Resets the current time to the number in the display RESET The display then shows CLo Recording the Calibration Level The procedure does not calibrate the unit It stores the CAL level to assure the unit was calibrated CODE Press the key until CAL and the current calibration HL3 level is displayed To recalibrate the unit press SOUND LEVEL with the microphone inserted in a calibrator SOUND The display will show SPL the calibrator level Wait LEVEL until the level is steady and press PAUSE RESET If the unit is slightly out of calibration gently adjust the CAL screw If the unit is more than a few decibels out of calibration it should be rechecked PAUSE Resets the calibration level Hold key down until the RESET display shows CAL Using a Printer The printout Figure 2 can include a heading a summary of the data event data to 3 histograms 1 or 2 percent time statistical distributions and 1 or 2 percent dose statistical distributions The histograms can be of 1 3 5 or 10 minute duration The histograms and statistical distributions can be text graphical or both The
32. he microphone to the collar or shoulder of the operator see Effects of Operator Presence and Figure 6 7 Press the RUN key and hold until you see the unit count 8 Install the security cover and attach the unit to the operator s belt or pocket 9 At the end of the workday remove the security cover and press PAUSE 10 Remove the unit from the operator 11 Press each function key and record the results or print the results on a printer 12 Press the ON OFF key until the display becomes blank If the unit is not going to be used for several days remove the battery As an Area Monitor 1 Turn on clear memory check battery and calibration as above 2 Connect microphone bracket to back of unit and clip microphone to the microphone bracket The microphone clip may be removed and the microphone screwed to the bracket before the bracket is mounted to the case see Figure 7 a 3 Mount the unit on a tripod see Figure 8 4 Aim the microphone up at a 70 degree angle to the noise source see Figure 5 5 Press RUN and install the security cover 6 After data is accumulated remove the cover press PAUSE RESET and record or print the data As a Survey or Event Monitor 1 Turn on clear memory check battery check calibration and secure microphone as above 2 Hold the instrument near not too near the operator s head and aim it up at about a 70 degree angle to the noise source 3 Press EVENT The display should re
33. he shirt collar or on the shoulder The microphone can be attached to a bracket for use as a sound level meter Or the unit can be mounted on a tripod for area surveys The M 27 is powered by a single 9 volt transistor battery with an 80 hour battery life A low battery indication is displayed 8 hours before the end of life of an alkaline battery PRINCIPLES OF OPERATION General The M 27 Noise Logging Dosimeter uses an 8 mm omnidirectional ceramic microphone buffered by a high impedance FET input stage The electronics utilizes low power circuitry for long battery life maximum stability and high reliability over a wide range of environmental conditions A block diagram of the M 27 is shown in Figure 3 Weighting Characteristics The M 27 has both A and C weighting characteristics as shown in Figure 4 For OSHA and most noise measurement requirements the A weighting should be used The A weighting has a response similar to the human ear The C weighting is used for measuring noise reduction in hearing protectors and for other scientific purposes ABSOLUTE MICROPHONE AMPLIFIER AND FET AND VALUE BUFFER FILTER CIRCUIT KEYBOARD aa ETE ous Ss CIRCUIT Ka 7 AND KEY 20 oT ADH SONTEN m ee ECODER OFF SET MICRO LOG aca COMPUTER CIRCUIT DECODER D MICRO AND CONTROL TO ISPLAY ie FREQUENCY FREQ e ie PRINTER DISPLAY CONNECTOR Figure 3 Block Diagram M 27 Dos
34. histogram LMIN Level of histogram printout MIN Number of minutes used to compute histogram TIME The statistical distribution Time number DOSE The statistical distribution Dose number STAT The number of 1 16 second intervals at a level LSTAT The statistical distribution level TESTING AND CALIBRATION Battery Test Press any key If the battery is low LOB AT will be displayed in the upper left corner of the display If the battery has at least 8 hours life LOBAT will be off If LOBAT is displayed after a day s use but not at the start of the day the readings are still good Battery Replacement Loosen the 2 screws on the back of the unit and remove the back Remove the battery from the cavity and carefully unclip the battery Replace with a new battery Take care to observe the polarity of battery and do not reverse the terminals For best results use a 9 volt alkaline battery Replace the battery in the compartment and check the display If it displays 3 dashes replace the back cover If not check the connections on the battery The M 27 is now operating in the pause mode Disconnecting the battery automatically erases stored data in memory To save data during battery change use the BX 9 Battery Change Adapter see page 47 NOTE When the unit is off the battery still powers the memory If the unit is not going to be used for a few days the battery should be removed Microphone Replacement
35. imeter RELATIVE RESPONSE DECIBELS 20 50 100 200 500 1000 2000 5000 10 000 20 000 FREQUENCY IN CYCLES PER SECOND Figure 4 Frequency Response Characteristics for A and C Scale Weighting It also has a 1 second Slow and a 125 second Fast time constant circuit Present OSHA requirements specify Slow Microcomputer Modes The M 27 is controlled by a MC146805 CMOS Microcomputer The system has 8192 bytes of RAM 6144 bytes of ROM a 33 segment LCD 24 programming switches serial and parallel printer outputs a V F converter for continuous dose integration and power down circuits to retain data when off The M 27 operates in one of the following 6 modes Reset Mode The M 27 enters the reset mode when the unit is reset or a battery is installed In this mode power is applied to the unit all previous data is cleared the internal switches are read the counter is cleared the pause register is set three dashes are placed on the display and the unit enters the wait mode Wait Mode The microcomputer waits for an interrupt to occur During the wait mode it continues to gather data from the voltage to frequency converter Otherwise the microcomputer is in a low power state When the 1 16 second interrupt occurs the unit enters the pause or run mode Pause Mode In this mode the Slow or Fast time constant sound level is computed and pause time and the elapsed or real time clocks are i
36. lock 600 Baud 85 dB Criterion Unit Unit 1 4 dB Exchange Rate Switch1 Switch 2 Switch 3 Ist CODE 2293 2nd CODE 13E 3 dB Community Noise A Weighting 80 dB High Serial Printer 30 126 dB Range Threshold Text and Graph 90 dB Upper Limit 70 dB Low Threshold NUL and CR Fast Time Constant 24 Hour Clock 2400 Baud 85 dB Criterion Unit Unit 7 3 dB Exchange Rate Switch 1 Switch 2 Switch 3 Canada Industrial Noise Monitoring A Weighting 90 dB High Parallel Printer 50 146 dB Range Threshold Text and Graph 115 dB Upper Limit 80 dB Low Threshold LF and CR Slow Time Constant 12 Hour Clock 600 Baud 90 dB Criterion Unit Unit 1 3 dB Exchange Rate Switch 1 Switch 2 Switch 3 Switch Positions Switch 1 and 2 select the M 27 functions Switch and 2 are read only on RESET and when the battery is replaced Switch 3 selects printer options Switch 3 is read at the start of each printout and may be changed without destroying data SWITCH 1 Position 1 On C weighting Off A Position 2 On 30 dB Range Off 50 dB Range Position 3 In 30 dB Range On 115 dB U L Off 90 dB U L In 50 dB Range On 140 dB U L Off 115 dB ULL Position 4 On Fast Off Slow Positions 5 6 Criterion Level Off Off 80 dB Off On 84 dB On Off 85 dB On On 90dB Positions SWITCH 2 Positions Off Off Off Off Off Off Off Off On On On On On On On On Position 5 Position
37. n blank When off data is retained Key also turns off Print and Events NOTE Data is not lost when the unit is off Data will be retained for the life of the battery The only ways to erase data are to hold down PAUSE RESET for 5 seconds or to remove the battery CODE Cycles through 7 steps Press the key for each step HL3 Allows the M 27 to display and print data 7 ways Also displays a code of internal switch settings Cycle Display Function Can Display Step Example Shows and Print 10EE Internal switch setup High Threshold Level data 2 1OEE T Internal switch setup Low Threshold Level data 3 IOEE A Internal switch setup 3 dB data IFE Internal print switches Prints all data 5 CPU Computer mode Prints raw data 6 1 59 Clock or elapsed time Sets clock 7 110 0 Calibrator level Sets calibration level In steps 1 to 3 only data for the HTL High Threshold Level LTL Low Threshold Level or 3 dB No Thresh old will he displayed or printed In step 4 data for HTL LTL and 3 dB will be printed Step 5 dumps raw data to the Computer Step 6 reads or resets the Clock Step 7 reads or stores the Calibrator level Sound Level Meter Keys SOUND Sound Level in decibels Will repeat each second until LEVEL another key is pressed To conserve power press RUN PAUSE or any other key to exit sound level when it is not needed PEAK The highest unweighted Peak Level in decibels during LEVEL Run Tim
38. ncremented At every interrupt the keyboard is checked to see if any key is pressed unless it is doing a previous calculation such as sound level when it may delay for up to 1 second If a key is pressed the computer enters the compute mode Otherwise it returns to the wait mode Run Mode The same as the pause mode except the data necessary to compute Lavg Leq Dose TWA SEL Peak Max Run Time Upper Limit as well as Event data is accumulated Compute Mode If a key has been pressed in the pause or run modes the M 27 will compute and display the desired function If the key is held down it will recompute it one second later using the data accumulated during that second If the data will not compute as an example Lavg will not compute if the sound level never exceeds the threshold level the display will either show three dashes or display LO If the print key has been pressed the processor will compute one line of print and send the data to the printer output The printer output may be terminated by pressing the ON OFF key until 0 5 is displayed Pressing PAUSE will cause the printer to stop Press PAUSE to continue When PSE is displayed the unit draws extra current and should not be left in this state ON OFF will exit PSE The computer continues to accumulate data during a printout For best results the computer should be placed in the pause mode during a printout When computing is completed the processor returns to the wait mode
39. ng the change will be ignored Switch 3 is read at the start of a printout It may be changed to allow printouts to different printers or computers without destroying the accumulated data Code Decoding The M 27 displays two different codes a 4 digit code can be decoded to show the position of 13 switch positions and a 3 digit code shows the position of 11 switch positions For the 4 digit code 1 Press CODE HL3 until a 4 digit code appears 2 Enter the code in the table 3 Convert from hex to binary see Table 1 4 Subtract 1 from first digit 2 becomes 1 and 1 becomes 0 5 Look up each position as described under Setting Internal Switches Table 2 4 Digit Code Table CODE BINARY f foo a MINUS 1 POSITION i SWITCH Example Code LOEE CODE O E E BINARY wm mm mo mo MINUS 1 0000 gu n SS POSITION xxx5 1234 5678 1234 SWITCH sw2 swi swi sw2 1 decodes to a 12 hour clock 0 decodes to A weighting 50 dB range 115 dB U L and Slow time constant The first E decodes to a 90 dB Criterion Level and a 5 dB exchange rate The last E decodes to a 90 and 80 dB thresholds For the 3 digit code 1 Press CODE HL3 until 3 or less digits code are displayed Leading zeros are not displayed 2 Enter code in table 3 Convert Hex to binary see Table 1 4 Look up each position in internal switch section Table 3 3 Digit Code Table
40. not be true if the noise is below the threshold level If the noise is continuous or impulsive then Lavg will be nearly equal to Leq If the noise is intermittent then Lavg will be several decibels less than Leq The time constant will cause the readings not taken with a 3 dB exchange rate to be greater than if there were no time constant For 3 dB it makes little difference The Peak Level will be greater than Slow Max unless the peak occurred while the instrument was in PAUSE and was changed to RUN a few seconds later Then Max Level might be greater than Peak Level U L Time will not count unless the level has exceeded the upper limit level for a total of one second In all of the above greater and less include almost equal Use of Lavg and TWA Time Weighted Average TWA is measured in decibels It is the accumulated noise dose integrated over eight hours The only difference l l l Table 4 Corrections for Computing TWA from Lavg between TWA and Dose is that TWA is expressed in decibels and Dose is expressed as a percent Values in this Table were computed from the formula TWA is equal to a continuous level which if constant for eight hours would produce the same Correction ER x Log Workday noise dose as the dose accumulated over the run time The average integrated sound level Lavg will be 2 8 equal to TWA at eight hours If the time is less than eight hours then TWA will be less than L
41. on a 1 minute histogram is 5 minutes of data If a 3 5 or 10 minute histogram is selected each line would be 15 30 or 60 minutes long with 5 or 6 levels per line It is possible to change the time base on the histogram in the middle of a printout see Figure 14 for example and page 31 for details If only TEXT was selected on the internal switches the graph portion would be omitted If GRAPH is selected the time and graph portion is printed This is useful for 40 column printers 800B THRESHOLD 1t MIN HISTOGRAM Sq EXCHANGE RATE 08 15 S 88 84 99 oo0ogdB Geep beepsdkessemeggberer eseshen 9308 OB 20 DO CAN 95 De OOOb ees ss desse ees RSOB 08 25 102 a0 75 90 9208 bb bs bn OAOp DD 30 99 100 Se 79 28106 ee eS 4 Gin eS F 9408 OB 35 AO 80 OO 87 8208 tone eS Sess 8208 08 40 85 D 90 92 8708 Pa ean a ee ae Se ee 8808 5 MIN HISTOGRAM 8 45 OG 86 82 82 Ss 8208 ey ere ee ee we OD gesch 880B o 15 81 oo OO OO OO OOOP F eao m G a ma 68dB Figure 14 Sample of Changing Time Base of Histogram Statistical Distributions Four separate statistical distributions are accumulated The TIME shows the percent time at each level The DOSE shows the accumulated dose at each level Both of the percentages depend on the time constant and the exchange rate so two separated distributions are accumulated see Figure 15 90dB THRESHOLD 5dB EXCHANGE RATE TIME STATISTICAL DISTRIBUTION 50dB 03 2 58 3 64 4 24 3 972 55
42. printout can be changed and edited before or during printing to print only desired data Data is not lost during a printout CODE To print only HTL LTL or 3 dB histograms and statis HL3 tical distributions hold key down until the one desired is displayed To print all 3 hold key down until all 3 are displayed PRINT Prints heading summary events and desired histo grams and distributions HIST 1 Prints 1 minute Histograms or 5 minutes per line If HTL LTL and 3 dB are displayed all 3 will be printed HIST 3 Prints 3 minute Histograms or 15 minutes per line HIST 5 Prints 5 minute Histograms or 30 minutes per line HIST 10 Prints 10 minute Histograms or 1 hour per line If HIST 1 3 5 or 10 is pressed during a printout the next line will print with the new time base for a clearer report STAT Prints a Time and a Dose statistical distribution PAUSE Pauses the printer to edit printout or adjust printer RESET The display shows PSE To continue printing press PAUSE again Other print keys will alter the printout To conserve power do not leave PSE on the display ON OFF will also exit print mode ON Stops the printout If the printer buffer contains data OFF the printer may run for several seconds after O 5 is displayed however the printout has stopped QUEST M 27 NOISE LOGGING DOS IMETER NAME WORK STATION CAL LEVEL 110 008 START TIME 08 15H M PEAK LEVEL 138 708 PEAK TIME 0O9 on WM EX
43. rough the Events with data The display shows the event number a CE if it is the Current Event or else a E for a previous Event As an example 12CE means 12 is the Current Event 3 E means 3 was a previous Event Only previous events with data will be displayed RUN Starts accumulating data for the Current Event PAUSE Stops accumulating data and cycles to the next Event RESET ON OFF Exits the Event mode Procedure to Accumulate Event Data To enter the Event mode press EVENT To accumulate data press RUN To stop press PAUSE RESET Press RUN and PAUSE RESET again to accumulate another event Press ON OFF to exit events The following keys can be used to read data in the current event or in any previous event CODE Cycles through HTL LTL and 3 dB Displays the cur HL3 rent time or elapsed time for the current event and the start time for any previous event L AVG The average or equivalent level for the HTL LTL or LEQ 3 dB for the event DOSE The percent Dose for the HTL LTL or 3 dB for the event TWA The Time Weighted Average for HTL or LTL or the SEL Sound Exposure Level for the event PEAK The Peak Level for the event LEVEL MAX The Maximum Level for the event LEVEL RUN The Run Time of the event TIME Setting the Clock If the clock is not set it functions as an elapsed time clock from the time the unit is reset The clock can be either a 12 or 24 hour clock depending on an internal switc
44. s set for serial printers with both text and graphs The E means it is set for 600 baud To convert from decimal to hex or binary refer to Table 1 To select different options set the switches by filling in Tables 2 and 3 As an example if A weighting 30 to 126 dB range and a 90 dB upper limit is desired then set the left switch positions 1 2 and 3 to down up and down Table 1 Decimal Hex Binary Conversion Chart DECIMAL HEX BINARY 0 A 0000 l l 0001 2 2 0010 3 3 0011 4 4 0100 5 5 0101 6 6 0110 7 O11 8 8 1000 9 9 1001 10 A 1010 1 B 1011 12 C L100 13 D 1101 14 E 1110 15 F 1111 For example an indication of 8E HEX converts to 1000 1110 BINARY To set the criterion level to 80 dB and the exchange rate to 3 dB set the next 4 positions down For a high threshold of 80 and a low threshold of 70 set the first 4 positions of the right switch to down up up and up To identify this unit as unit 0 set the next three switches down If the unit number is set to zero the code will not show the leading zero All the switch positions in a column must be set to get the correct settings Notice as an example the 115 dB upper limit switch could be up or down depending on the range setting Also the threshold settings are encoded The M 27 reads the switches 1 and 2 only when the unit is reset or a battery is reconnected If the switch positions are changed when the unit is operati
45. tance a 10 minute histogram for part of the time and a 1 minute histogram for another The M 27 remembers previous PRINT keystrokes and will print only that data unless the keystroke has been cleared Sample Printouts Heading A heading is printed when PRINT is pressed It allows the user to write in identification data see Figure 10 QUEST M 27 NOISE LOGGING DOSIMETER NAME We age E Ha eee EE EES EH Figure 10 Sample Heading Printout Summary The summary data includes parameter data of how the M 27 is set up and a summary of all the M 27 functions see Figure 11 W SHT ING A 8nr DOSE 4 0 Snr E 104 4 Bnr DOSE Figure 11 Sample Summary Data Printout Events The event data is printed for events with data It includes start time run time peak and max levels as well as accumulated data for all three dosimeters see Figure 12 EVENT START TIME 21H M 16 THRE HOL S008 THRE HOLT 16 f HANGI RATE 7 gt m EA D Figure 12 Sample Event Data Printout Histograms Three separate histograms are computed as the data is accumulated with the appropriate exchange rate and excluding data less than the threshold Each minute an integrated average level is computed and stored see Figure 13 For example in the following histogram 90dB THRESHOLD 5dB EXCHANGE RATE 1 MIN HISTOGRAM 10 15 103 97 110 96 107dB 105dB 10 20 98 98 99 QO 71dB backen
46. ter Connections The M 27 can send its data to personal computers over the RS 232 port In general the computer and M 27 are set up similar to a serial printer The computer is programmed to be a data terminal and the data is read into the computer If the data is saved in an ASCII file it may be edited with a word processor program Consult the Quest factory for hints on using the M 27 with specific computers Printer Pinouts The 20 pin connector is numbered from right to left starting with in the upper right corner 2 in the lower right corner and 20 in the lower left corner when looking at the M 27 Serial Parallel Pin 1 Data Signal Strobe 5 to 5 minus the battery voltage 300 ohm impedance Pin 3 Data0 Output of HC CMOS driver Pin 5 Data1 Output of HC CMOS driver Pin 7 Data2 Output of HC CMOS driver Pin 9 Data3 Output of HC CMOS driver Pin 11 Data4 Output of HC CMOS driver Pin 13 Data5 Output of HC CMOS driver Pin 15 Data6 Output of HC CMOS driver Pin 17 Data 7 Output of HC CMOS driver Pin 20 DSR Busy Input gt 3 volts 1 Input lt 1 volts 0 Pins 2 4 6 8 Ground 10 12 Pin 14 External battery minus Pin 16 External battery plus Pin 18 19 No connection EXTENDING BATTERY LIFE Since the M 27 stores data even when it is turned off the battery should be removed if it is not to be used for a few days he M 27 may draw additional current when connected to a printer
47. titude Ettel a Eet g e 19 OPERATING PROCEDURE neue egeuugeet eu eg EEN Nee EENEG NEEN 19 As a Personal Noise Dosimeter NEEN 19 AS an Area Monitor eege Gegen ES Nee ian ana aa eaaa 20 AS a Survey OF Event MOMOR sacivcicescsinens deeg ee ege EES ENEE SEN EEEEAER 21 Effects of Operator s Presence eege 22 Use with Wun ege 22 Using a Printe EE 23 Connections to EE geed EE E 24 Sample PVM TEE 24 Memory MAD sccscs cnt na oes EE ces EE a A aA EA EE 30 D Egeter Eeer 31 E lune Tt E 32 Z EXTENDING BATTERY LIFE gustegoseggeg enee ge ege ENEE N RENSE ia E 33 INTERNAL SWITCHES E 34 SWITCH POSIUONS E 36 Setting le EE 38 COde DECOM e PAn E E ER 41 TPROUBLESHOG TIN LE 42 INTERPRETING REH Eege gege 43 Use of Lavd and KEE 43 Estimating TWA from LAV Gs cciinsccsnessnennucsevanonnsctavunnmuareveenmcasrenninnnen bunnies ees 44 ACCURACY Of REAGING S sssri enseina aranana epa aaraa EEEE 44 Hints and Good E 44 Considerations of Measurement and Accuracy EE 46 ACCESSORIES vishensnitiavincissinucoiexsapasnaulveauceaertaacoucacuanunctandediexawenaeudenenatennudedbonnennan 47 QUEST SERVICE AND WARRANTY POLICY 48 FCC COMPLIANCE AND CAUTIONARY NOTE User is cautioned that changes or modifications not expressly approved by the party responsible for compliance could void the user s authority to operate the equipment NOTE This equipment has been tested and found to comply with the limits for a class B digital device pursuant to part 15 of the FCC R
48. to two thirds If a 40 column printer is used turning off TEXT or GRAPH will reduce length of histograms or statistical distribution Printing a 3 5 or 10 minute histogram also reduces the printout kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk Remember data is not erased in the M 27 by any printout The only way data can be lost is by RESET removing the battery or having a dead battery If a printout is not as desired another printout may be made See page 47 for preserving data during battery change by using a BX 9 accessory PEPE kk kk 2 I ke 2 kee EE 2 2 ke kee kee ke e kee ek ek 2 2 9 oo 2 2 ee 9K oo oe ke ke aK a 2 2 2 2k aK oo Other keys change the way data is printed The keys can be pressed while the printer is printing not printing or in pause As an example if HIST 5 is pressed part way through the histogram the rest of the histogram will be a 5 minute histogram PAUSE causes the printer to pause while other keys are pressed to redefine the printout Pressing PAUSE a second time will continue the printout PAUSE must always be pressed twice once to stop the printer and once to continue ON OFF will stop the printout If the printer continues to print after pressing PAUSE or ON OFF the printer has received an amount of data from the M 27 and stored it in a buffer In most printers the buffer can be turned off if desired See printer manual for details Printer Setup Serial
49. trument are clipped and act as if they were at the maximum level of either 146 dB on the 50 dB range or 126 dB on the 30 dB range Minimum noise levels are either at the bottom of the range or at the noise floor of the instrument For readings which do not have a lower threshold the accumulated noise will be at these levels Crest factor is an almost meaningless term for instruments with crest factors in excess of 30 dB The M 27 is capable of measuring pulses as short as 1 millisecond with a peak amplitude of 143 dB and a background level of 80 dB This is a pulse range of 63 dB The crest factor would depend on how often this pulse occurred but could be greater than 60 dB ACCESSORIES Model WS 5 Windscreen Refer to page 22 on how to use the windscreen with the M 27 microphone Model MB 1 Microphone Bracket Refer to page 20 Cables 59 818 36 pin Centronics parallel cable 59 843 25 pin serial female connector cable 59 874 25 pin serial male connector cable 59 758 Computer booster cable 59 879 9 pin serial female Tripods Quest supplies two models of tripods for use with the M 27 as an area monitor For use refer to page 21 BX 9 Battery Change Adapter To preserve stored data in the M 27 memory during a battery change the BX 9 Battery Change Adapter may be used The BX 9 allows you to remotely power the M 27 by plugging it into the printer output connector and therefore keeping the dosimeter powered while disconnecting the ba
50. ttery and replacing it with a fresh one The BX 9 utilizes pins number 14 and 16 on the printer connector Service Policy The Quest product you have purchased is one of the finest acoustic instruments available It is backed by our full one year warranty which seeks complete customer satisfaction This is your assurance that you can expect prompt courteous service for your equipment from the entire Quest service organization Should your Quest equipment need to be returned for repair or recalibra tion please contact the Service Department at 800 245 0779 USA or Fax 262 567 4047 for a Return Authorization Number The RA number is valid for 30 days and must be shown on the shipping label and purchase order cover letter If you are unable to return instruments in that time call for a new RA number Send it prepaid and properly packed in the original shipping carton directly to Quest Technologies 1060 Corporate Center Drive Oconomowoc WI 53066 U S A Repair or replacement work done under warranty will be performed free of charge and the instrument will be returned to you prepaid Your copy or a photocopy of the Quest Registration Card will serve as proof of warranty should the factory require this information If for any reason you should find it necessary to contact the factory regarding service or shipping damage please direct your calls or letters to the attention of the Service Manager Quest Technologies 262 567 9157 or
51. ules These limits are designed to provide reasonable protection against harmful interference in a residential installation This equipment generates uses and can radiate radio frequency energy and if not installed and used in accordance with the instructions may cause harmful interference to radio communications However there is no guarantee that interference will not occur in a particular installation If this equipment does cause harmful interference to radio or television reception which can be determined by turning the equipment off and on the user is encouraged to try to correct the interference by one or more of the following measures Reorient or relocate the receiving antenna Increase the separation between the equipment and receiver Connect the equipment into an outlet on a circuit different from that to which the receiver is connected Consult the dealer or an experienced radio TV technician for help INTRODUCTION The QUEST M 27 Noise Logging Dosimeter is a microcomputer based sound analyzing instrument for accumulating displaying and sending data to serial or parallel printers or computers The M 27 functions as a personal noise dosimeter an area monitor or as a survey events monitor see Figure 1 Personal Noise Dosimeter Accumulates noise data for OSHA hearing conservation OSHA engineering controls and equal energy noise dosimetry Accumulates peak and maximum levels Accumulates 1 minute histograms an
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