Page 1 INSTRUCTION MANUAL Sound Level Measuring Amplifi er NA-42 3-20-41 Higashimotomachi, Kokubunji, Tokyo 185-8533, Japan http://www.rion.co.jp/english/...
Page 3: Organization Of This Manual
Organization of this manual This manual describes the features and operation of the Sound Level Measuring Amplifi er NA-42. The manual contains the following sections. Outline Gives basic information on the confi guration and features of the unit, and contains a block diagram.
Page 5: For Safety
FOR SAFETY In this manual, important safety instructions are specially marked as shown below. To prevent the risk of death or injury to persons and severe damage to the unit or peripheral equipment, make sure that all instructions are fully understood and observed.
Page 6: Precautions
Precautions Operate the unit only as described in this manual. Protect the unit from shocks and vibration. Be especially careful not to touch the microphone membrane to avoid damage. The membrane is an extremely thin metal fi lm which can be damaged easily. Ambient conditions for operation of the unit are as follows: temperature range -10°C to +50°C, relative humidity 10% to 90%.
Page 7 Caution Some pins of the INPUT connector carry a high voltage. To prevent the risk of electric shock, never insert a metal clip or any other pointed object into the input connector.
Page 8: Table Of Contents
Contents Organization of this manual ............i FOR SAFETY ................iii Precautions ..................iv Outline ....................1 Controls and Features ..............4 Front Panel ................4 Rear Panel ................8 Display ................... 10 Preparations ..................13 Power Supply ................13 Inserting Batteries ..............13 AC Adapter ................14 Microphone and Preamplifi er Connection ........15 Calibration ................20 1) Electrical calibration ............20...
Page 9 Bar Graph Display Range (20 dB/50 dB) Setting .....46 Menu Settings ................47 External Filter Setting .............52 Backlight On/Off ..............53 Comparator ...................54 Serial Interface ................58 Transfer Protocol ..............58 Local Mode/Remote Mode .............59 Transfer Sequence ..............61 Error Processing ..............63 Control Operation in Remote Mode ........63 Command Format ..............64 Commands ................67 Technical Reference ..............
Page 10 viii...
Page 11: Outline
Outline The NA-42 is a sound level measuring amplifi er covering a wide frequency range and level range. It allows connection of various types of microphones such as the low-noise microphone UC-34P or the 100-kHz range microphone UC-29. For general acoustic measurements and for environmental measurements, selectable frequency weightings (A, C, and FLAT) and time weightings (FAST, SLOW, IMPULSE) are provided.
Page 12 Outline Connector E OVER OVER CAL signal Input A, C -10 dB +10 dB +10 dB +10 dB OVER FLAT -20 dB +20 dB +20 dB FLAT AC OUT CAL ADJ 20 Hz 20 kHz External Antialiasing filter OVER filter FROM FILTER FILTER...
Page 13 Outline Example: Sensitivity -29.9 to -20.0 Adjustment by CAL ADJ (Span of adjustable range: 10 dB) 0 dB 0 dB 0 dB 0 dB -10 dB +10 dB +10 dB +10 dB -20 dB +20 dB +20 dB Main Unit Gain Diagram...
Page 14: Controls And Features
Controls and Features Front Panel Handle SOUND LEVEL NA-42 MEASURING AMPLIFIER LEVEL RANGE LEVEL RANGE key Display A/C/FLAT key 20dB/50dB 20 dB/50dB key SENS key CAL key FAST/SLOW/IMP key FAST /SLOW SENS /FLAT /IMP Setting up/down Sensitivity control keys MENU...
Page 15: Sensitivity Control
Controls and Features FAST/SLOW/IMP key Selects the time weightings. Available settings are FAST, SLOW, and IMP (IMPULSE). Sensitivity control Serves to adjust the unit to match the microphone sensitivity. 20 kHz key Switches the low-pass fi lter (LPF) on and off. When the fi lter is on, sig- nal components 20 kHz or above are sharply attenuated.
Page 16: Input Connector
Controls and Features 20 Hz key Switches the high-pass fi lter (HPF) on and off. When the fi lter is on, signal components 20 Hz or below are sharply attenuated. Lp/Lmax/Lpeak key Switches the measurement mode to sound level L , maximum sound level L , or peak sound level L...
Page 17 Controls and Features Caution To prevent the risk of electric shock, never insert a metal clip or any other pointed object into the input connector. Setting up/down keys These keys are used for setting the microphone sensitivity or for mak- ing a selection from a menu.
Page 18: Rear Panel
Controls and Features Rear Panel BATT BOX Battery holder Battery holder button AC OUT FILTER AC OUT connector LOCK UNLOCK External filter connectors FROM DC OUT FILTER DC OUT connector Name plate EXT 6V PREAMP External power supply ±12V ±45V FILTER connector SERIAL...
Page 19 Controls and Features Name plate The serial number of the unit is shown here. External power supply connector The dedicated AC adapter (NC-98C) is connected here. Comparator output This is an open-collector output with an A contact and COM contact. PREAMP power selector Selects ±12 V or ±45 V as power supply voltage for a connected pream- plifi er.
Page 20: Display
Controls and Features Display INSERT COMP REMOTE COMP REMOTE Battery indicator INSERT UNDER OVER UNDER OVER Calibration value Level range Level range (upper limit) (lower limit) Bar graph indicator PEAK MAX OVER PEAK MAX OVER Units Measurement value readout FAST SLOW Time weighting Frequency weighting...
Page 21 Controls and Features Bar graph indicator Corresponds to the level of the input signal. PEAK MAX OVER "MAX" is shown here if the L function is selected. When the L peak function is selected, "PEAK" is shown. If an overload condition has occurred for either L or L , the indi- peak...
Page 22 Controls and Features Level range (lower limit) The lower limit of the level range is shown here. When the bar graph range is 50 dB, the value shown here corresponds to (level range -50 dB). When the bar graph range is 20 dB, the value shown here corresponds to (level range -20 dB).
Page 23: Preparations
Important · While inserting or removing batteries, support the battery holder by hand. NA-42 Battery holder · Take care not to insert batteries with wrong polarity. · While not using the unit, the batteries should be removed.
Page 24: Ac Adapter
Preparations Battery life Alkaline batteries LR14 approx. 14 hours Manganese batteries R14P approx. 6 hours • The above values were determined under the following conditions. 20°C 50% RH, microphone UC-53A, preamplifi er NH-17, power supply for preamplifi er ±12 V, backlight OFF, communications OFF, continuous operation.
Page 25: Microphone And Preamplifi Er Connection
Preparations Microphone and Preamplifi er Connection The proper selection of microphone and preamplifi er depends on various factors, such as the level to be measured, frequency range, purpose of the measurement, etc. (For details, see the section "Technical Reference" start- ing on page 81.) Connect the microphone/preamplifi er to the INPUT connector.
Page 26 Microphone UC-53A Preamplifier NH-17 2. Confi rm that the NA-42 is turned off. Then connect the preamplifi er to the NA-42 with the cable of the preamplifi er. Microphone/preamplifier If you want to extend the cable, use the optional condenser micro- phone extension cable series EC-04.
Page 27 If the micro- phone is accidentally dropped, sensitivity and frequency response may be impaired. 2. Confi rm that the NA-42 is turned off and that the PREAMP power selector on the rear panel is set to ±12 V. BATT BOX...
Page 28 Preparations 3. Using the optional condenser microphone extension cable series EC- 04, connect the preamplifi er to the NA-42. Condenser microphone extension cable series EC-04 Length Length Model Model EC-04 EC-04C 30 m (reel section) + 5 m (link section)
Page 29 Adapter UA-12 Preamplifier NH-05 2. Confi rm that the NA-42 is turned off. Then connect the preamplifi er to the NA-42 with the cable of the preamplifi er. If you want to extend the cable, use the optional condenser micro- phone extension cable series EC-04.
Page 30: Calibration
1. Turn the unit on. 2. Press the SENS key. 3. Use the setting ( , ) keys to set the value for the microphone (preamplifi er). SOUND LEVEL NA-42 MEASURING AMPLIFIER LEVEL RANGE 20dB/50dB SENS key CAL key FAST...
Page 31 Preparations The sensitivity setting is the microphone sensitivity plus the pream- plifi er loss. The microphone sensitivity is the value given on the calibration chart attached with the microphone (see below). The microphone sensitivity Calibration chart...
Page 32 Preparations The preamplifi er loss (loss caused by microphone capacitance and preamplifi er capacitance) can be determined from the chart below, according to the equipment combination. 1-inch 1/2-inch 1/4-inch Microphone UC-27 UC-30 UC-52 UC-53A UC-57 UC-59 UC-54 UC-29 UC-32P UC-31 Preamplifier UC-33P NH-04, NH-12...
Page 33 Preparations 4. Press the SENS key on the front panel to return to the measurement screen. 5. Set the level range according to the sensitivity setting, as shown in the table below. Conditions Microphone Preamplifier gain Level range (dB) 0 dB / 20 dB sensitivity (dB) -19.99 to -10.00 -29.99 to -20.00...
Page 34: Or Sound Calibrator Nc-74
1. Turn power to the pistonphone NC-72A or sound calibrator NC-74 off. 2. Turn power to the NA-42 on. 3. Press the SENS key on the front panel. SOUND LEVEL NA-42...
Page 35 Preparations The microphone sensitivity Calibration chart The preamplifi er loss (loss caused by microphone capacitance and preamplifi er capacitance) can be determined from the chart below, according to the equipment combination. 1-inch 1/2-inch 1/4-inch Microphone UC-27 UC-30 UC-52 UC-53A UC-57 UC-59 UC-54 UC-29...
Page 36 Preparations 5. Press the SENS key on the front panel to return to the measurement screen. 6. Use the LEVEL RANGE keys to set the level range to "100" if the NC-74 is used, or to "120" if the NC-72A is used. Level range setting Select FAST with NC-74: 100...
Page 37 C C l l a a s s s s L L S S / / C C S S e e r r . . N N o o . . 11. Turn power to the NA-42 and pistonphone NC-72A or sound calibra- tor NC-74 off.
Page 38 Adjust the NA-42 as follows, depending on the mi- crophone in use. Calibration value Nominal outer...
Page 39: Insert Cal Calibration
The NA-42 allows calibration using the "Insert CAL" method. For this method, a dedicated preamplifi er is used. 1. Turn power to the NA-42 off and connect the Insert CAL preampli- fi er NH-08 and the microphone. 2. Turn power to the NA-42 on.
Page 40 Preparations 8. Press the CAL key to activate the calibration mode. INSERT Calibration value Level range value Measurement value FAST Calibration example for level range 100 Measurement parameters are automatically set to C weighting and FAST. 9. Use the supplied screwdriver to adjust the sensitivity control on the front panel to the calibration value (94.0 dB in the example shown above).
Page 41 A COM NA-42 rear panel This is an example for the level range 120 dB. 1. Before making any connections, turn power to the NA-42 and to the external device off. Then connect the device and turn power on. SOUND LEVEL...
Page 42 Preparations 2. Set the level range to 120 and press the CAL key. Level range value Measurement value FAST 3. The AC OUT and DC OUT connectors carry a signal that corre- sponds to the displayed measurement value. (The AC output signal is a 1 kHz sinusoidal wave signal.) Use this signal to calibrate the external device.
Page 43: Using A Tripod
Preparations Using a Tripod When mounting the microphone on the optional tripod, fi rst fasten the mi- crophone holder to the tripod. Microphone/preamplifier Connector Microphone holder EC03001 All-weather windscreen tripod ST-81 Microphone holder UA-90 NH-17, NH-11, NH-12 EC03001 NH-01, NH-04, NH-05, NH-06, NH-34 The EC03001 is supplied with the condenser microphones EC-04, EC-04A, and EC-04B.
Page 44: Using A Windscreen
Preparations Using a Windscreen When making outdoor measurements in windy weather or when measuring air conditioning equipment or similar, wind noise at the microphone can cause measurement errors. To prevent this, an optional windscreen can be mounted to the microphone. For details on the effect of the windscreen upon the measurement, please refer to "Technical Reference"...
Page 45: Using The Prop-Up Feet
The unit can be tilted by fl ipping out the prop-up feet. Tilt the feet until they snap in place. Important When using the prop-up feet, do not place objects on top of the NA-42 and do not push down on the unit. Do not push Prop-up feet...
Page 46: Measurement
Measurement Power-On Important Preamplifi er power supply Normally, the PREAMP power selector on the rear panel should be set to ±12 V. If wishing to set the selector to ±45 V, fi rst make sure that the preamplifi er (microphone) is compatible with this voltage.
Page 47 Measurement When the unit is turned on, the same settings as used before the unit was turned off are reestablished (resume function), and measurement starts. Settings memorized by Settings not memorized by resume function resume function Level range Calibration High-pass filter Backlight status Low-pass filter Microphone sensitivity...
Page 48: Level Range Setting
Measurement Level Range Setting Setting procedure Use the LEVEL RANGE keys to select an appropriate setting, where the OVER or UNDER indication does not appear in normal operation. If the input signal level is too high for the selected range, the indication OVER appears.
Page 49: Frequency Weighting Setting
Available frequency weighting settings are A weighting, C weighting, and FLAT. Setting procedure Press the A/C/FLAT key to select the desired setting. Each push of the key cycles through the following settings: A FLAT SOUND LEVEL NA-42 MEASURING AMPLIFIER LEVEL RANGE 20dB/50dB Frequency weighting FAST SENS...
Page 50: Time Weighting Setting
Available time weighting settings are FAST, SLOW, and IMP (impulse). Setting procedure Press the FAST/SLOW/IMP key to select the desired setting. Each push of the key cycles through the following settings: FAST SLOW FAST. SOUND LEVEL NA-42 MEASURING AMPLIFIER LEVEL RANGE 20dB/50dB Time weighting FAST FAST/SLOW/IMP...
Page 51: L P / L Max / L Peak Setting
L (peak sound level) peak (maximum sound level) 1. Press the Lp/Lmax/Lpeak key to select the L setting. The indica- tion "MAX" appears on the display. SOUND LEVEL NA-42 MEASURING AMPLIFIER LEVEL RANGE 20dB/50dB FAST /SLOW SENS /FLAT...
Page 52 Measurement 4. The RESET key can be used to reset the hold value. SOUND LEVEL NA-42 MEASURING AMPLIFIER LEVEL RANGE 20dB/50dB FAST /A/C SENS /SLOW FLAT /IMP MENU 20Hz 20kHz 20Hz 20kHz (LIGHT) INPUT POWER Lp/Lmax /Lpeak RESET EXT FILTER...
Page 53 3. If the hold value has caused overload, PEAK OVER is shown. PEAK OVER SLOW 4. The RESET key can be used to reset the hold value. SOUND LEVEL NA-42 MEASURING AMPLIFIER LEVEL RANGE 20dB/50dB FAST /A/C /SLOW...
Page 54: Low-Pass Filter Setting
Press the 20 kHz key to toggle the 20 kHz low-pass fi lter between ON and OFF. When the setting is ON, signal components 20 kHz or above are sharply attenuated. SOUND LEVEL NA-42 MEASURING AMPLIFIER LEVEL RANGE 20dB/50dB FAST...
Page 55: High-Pass Filter Setting
Press the 20 Hz key to toggle the 20 Hz high-pass fi lter between ON and OFF. When the setting is ON, signal components 20 Hz or below are sharply attenuated. SOUND LEVEL NA-42 MEASURING AMPLIFIER LEVEL RANGE 20dB/50dB FAST...
Page 56: Bar Graph Display Range (20 Db/50 Db) Setting
Press the 20 dB/50 dB key to toggle between the two settings. Each push of the key switches between the following settings: 20 dB 50 dB 20 dB etc. SOUND LEVEL NA-42 MEASURING AMPLIFIER LEVEL RANGE 20dB/50dB 20 dB/50 dB key...
Page 57: Menu Settings
Measurement Menu Settings Settings for preamplifi er gain, SOUND LEVEL insert ON/OFF, measure- NA-42 MEASURING AMPLIFIER LEVEL RANGE ment value readout resolu- tion, serial communication, and comparator measurement 20dB/50dB conditions are made using FAST SENS /SLOW menus. /FLAT Setting up/down keys...
Page 58 Measurement Each push of the MENU (LIGHT) key cycles through the following menu numbers: 4.0 (4.1 4.2)* 5.0 (5.1 5.4)* measurement screen *1 Appear when 9600 or 19200 was set with menu 4.0. *2 Appear when menu 5.0 is set to ON. 3.
Page 59 Measurement Menu setting contents Menu 1 Preamplifi er gain 0 dB/20 dB When set to 20 dB, pin E of the INPUT connector carries a micro- phone bias voltage of 30 V. 0 dB: This setting should be selected normally. 20 dB: Select this setting if the UC-34P (UC-34, NH-34) is con- nected and low-level measurement is to be carried out.
Page 60 Measurement Menu 3 Serves to set the measurement value readout resolution. 0.1 dB: Measurement values are displayed down to fi rst decimal place (0.1 dB readout resolution). The update interval is 1 second. 0.01 dB: Measurement values are displayed down to second decimal place (0.01 dB readout resolution).
Page 61 Measurement Menu 5.0 Sets the comparator to ON or OFF. Comparator function is disabled. Comparator function is enabled. Menu 5.1 Sets the comparator level. The comparator level setting range is 0 to 180 dB, in 1-dB steps. Menu 5.2 Sets the comparator delay time. The comparator delay time setting range is 0 to 9 seconds, in 1-second steps.
Page 62: External Filter Setting
EXT 6V PREAMP ±12V ±45V FILTER SERIAL COMP OUT A COM 2. Press the EXT FILTER key to route the signal through the external fi lter. SOUND LEVEL NA-42 MEASURING AMPLIFIER LEVEL RANGE 20dB/50dB FAST /SLOW SENS /FLAT /IMP MENU 20Hz...
Page 63: Backlight On/Off
Press and hold the MENU (LIGHT) key for at least 2 seconds to set the LCD backlight to ON or OFF. When set to ON, the backlight will make the screen easy to read also in dark locations. SOUND LEVEL NA-42 MEASURING AMPLIFIER LEVEL RANGE 20dB/50dB FAST...
Page 64: Comparator
Note The comparator function is based on the sound level , not on the peak sound level L peak To turn the comparator function ON or OFF, SOUND LEVEL NA-42 use menu 5.0. MEASURING AMPLIFIER LEVEL RANGE 20dB/50dB FAST /SLOW...
Page 65 Comparator COMP While comparator function is operating, the indication COMP is shown. In the bar graph indication, the bar corresponding to the comparator refer- ence level remains constantly on. For example, when the comparator level is set to 75 dB, the 75 dB point on the bar graph scale lights up.
Page 66 Comparator Auto reset function The auto reset function is set with menu 5.3 ( "Menu Settings", p. 51). When set to ON, the comparator output, once triggered, will be reset after the time set with menu 5.4 when the sound level remains below the com- parator level for an extended time.
Page 67 Comparator Reset operation When the comparator output was activated, it can be reset in three ways. (1) Auto reset As described above, when auto reset is ON, the comparator output will be reset automatically after activation when the auto reset time has elapsed.
Page 68: Serial Interface
Serial Interface The NA-42 incorporates a serial interface that can be used to set measurement parameters and control measurement using commands sent from a computer. Measurement results can also be sent to the computer. Transfer Protocol Transfer principle: asynchronous, half-duplex...
Page 69: Local Mode/Remote Mode
Serial Interface Local Mode/Remote Mode Local mode In this mode, the controls on the panel of the NA-42 are used to op- erate the unit. Immediately after being turned on, the unit is always in local mode. Remote mode In this mode, the NA-42 operates in response to commands sent from a computer.
Page 70 Cross-wired serial cable (null modem) 3. Set the power switch of the NA-42 to ON. 4. Make the required menu settings at the NA-42 (see page 50). Menu 4.0 Select the transfer rate of serial communication. Menu 4.1 Set the ID number.
Page 71: Transfer Sequence
Transfer Sequence Sending of commands In order to control the NA-42 from a computer or to retrieve measurement data, certain commands must be sent to the NA-42. The data exchange must be performed according to certain rules, to ensure that both the NA-42 and the computer recognize the commands and data properly.
Page 72 Serial Interface Computer NA-42 RMT1**<CR><LF> Link established <ACK>READY<CR><LF> (Setting command) <CR><LF> <ACK>READY<CR><LF> Setting command (Data request command) <CR><LF> (Data) <EOT><CR><LF> Data request command RMT0**<CR><LF> Link terminated ** is the ID number. <ACK>: Control code 06 (acknowledge) <CR>: Control code 0D (carriage return) <LF>:...
Page 73: Error Processing
Control code 15 Control Operation in Remote Mode While the NA-42 is in remote mode, only the MENU (LIGHT) key and RE- SET key are active. Pressing the MENU (LIGHT) key for at least 2 seconds allows turning the display backlight on and off, and the RESET key in remote mode serves for switching back to local mode.
Page 74: Command Format
Serial Interface Command Format Commands that can be used by the NA-42 consist of 3 characters (3 bytes), usually followed by a parameter which specifi es the action range of the com- mand. <CR> <LF> Command Parameter Terminator There are two types of parameters: •...
Page 75: Command List
Serial Interface Command List Command Function See Page Select local mode/remote mode RMTn1n2n3 RMT? Get ID number and remote mode status RNGn Set level range RNG? Get level range status TMCn Set time weighting TMC? Get time weighting setting Set frequency weighting WGTn WGT? Get frequency weighting setting...
Page 76 Serial Interface Command Function See Page CMPn Set comparator function to On/Off CMP? Get comparator function status CMSn1n2n3n4n5n6n7 Make comparator function settings CMS? Get comparator function settings Get version information VER? Set preamplifier gain to 0 dB/20 dB PREn Get preamplifier gain and setting of rear-panel PRE? PREAMP power selector Set Insert CAL...
Page 77: Commands
= 0 Local mode n1 = 1 Remote mode n2 n3 = 00 to 15 Set ID number. NA-42 specifi ed by ID number receives the command. RMT? Get ID number and remote mode status Output data format p1 p2 p3<EOT><CR><LF>...
Page 78 Serial Interface TMC n Set time weighting for main processing FAST SLOW TMC? Get time weighting setting Output data format p<EOT><CR><LF> p corresponds to n of TMC WGT n Set time frequency weighting A weighting C weighting FLAT response WGT? Get time frequency weighting setting Output data format p<EOT><CR><LF>...
Page 79 Serial Interface SNS? Get sensitivity setting Output data format p1p2p3p4p5<EOT><CR><LF> For setting the sensitivity down to one decimal point when the readout resolution is set to one decimal point, p5 becomes "0". LPF n Set low-pass fi lter setting n = 0 n = 1 20 kHz LPF ?
Page 80 Serial Interface CAL n Set calibration mode n = 0 Calibration OFF n = 1 Calibration ON CAL? Get calibration mode status Output data format p<EOT><CR><LF> p = 0 Calibration OFF p = 1 Calibration ON BAT? Get battery capacity status Output corresponds to status of battery capacity indicator on display.
Page 81 Serial Interface DOD? Get measurement data Returns a value corresponding to the display indication. Output data format · When readout resolution is set to one decimal point p1p2p3p4p5,p7<EOT><CR><LF> p1 to p5 : Indicated measurement value p4 : Taken as "." When the integer is 1 or 2 digits, the empty p1 and/or p2 part is padded with spaces.
Page 82 Serial Interface DOF n Output sound pressure level or sound level every 0.1 sec- onds in non-protocol mode n = 0 Sound pressure level or sound level output OFF (This carried out the same processing as for the following <SUB>.) n = 1 Sound pressure level or sound level output Output data format is the same as for DOD? command.
Page 83 Serial Interface MAX n Set L (maximum sound level) function to On/Off n = 0 Maximum hold OFF n = 1 Maximum hold ON Get L MAX? function status Output data format p<EOT><CR><LF> p = 0 p = 1 active Set L PEK n (peak sound level) function to On/Off...
Page 84 Serial Interface Reset hold value This command is active during L , and compara- peak tor operation. CMP n Set comparator function to On/Off n = 0 Comparator OFF n = 1 Comparator ON CMP ? Get comparator status Output data format p<EOT><CR><LF>...
Page 85 Serial Interface CMS n1 n2 n3 n4 n5 n6 n7 Make comparator function setting n1 to n3: Set comparator level to 000 to 180 n1 is the fi rst digit, n2 the second digit and n3 the third digit. When the setting value is only 1 or 2 digits, the empty part is padded with zeros.
Page 86 Serial Interface VER? Get version information Output data format p1p2p3<EOT><CR><LF> p2: Taken as "." PREn Set preamplifi er gain to 0 dB or 20 dB n = 0 0 dB n = 1 20 dB PRE? Get preamplifi er gain and setting of rear-panel PREAMP power selector p1p2<EOT><CR><LF>...
Page 87 Serial Interface INSn Set Insert CAL n = 0 n = 1 INS? Get Insert CAL setting Output data format p<EOT><CR><LF> p corresponds to n of INS BARn Set bar graph display width n = 0 50 dB n = 1 20 dB BAR? Get bar graph display width...
Page 88 Serial Interface DOF Transfer Sequence Computer NA-42 DOF1<CR><LF> Continuous output of sound pressure level (Data) EOT<CR><LF> or sound level every 100 ms (0.1 seconds) (Data) EOT<CR><LF> <SUB> Output terminated The sound pressure level or sound level output updated every 0.1 seconds stops when <SUB>...
Page 89 Serial Interface Allowable remote mode commands in various operation conditions indicates that command is allowed (valid). × indicates that command is not allowed (invalid). Normal Command Calibration Comparator peak operation measurement Content: Others related commands RMT0n2n3 × Content: Data related commands ×...
Page 90 Serial Interface Normal Calibration Comparator Command measurement peak operation Content: Others related commands (with ?) VER? × RMT? × BAT? × Content: Front panel key related commands (with ?) RNG? × TMC? × WGT? × LPF? × HPF? × EXT? ×...
Page 91: Technical Reference
Technical Reference Microphone and Preamplifi er Selection When making measurements using a condenser microphone and preamplifi er combination, suitable models must be selected according to the measurement level, frequency range, and other factors. Condenser microphones (sample listing) Type UC-53A UC-52H UC-34 (P) UC-29 UC-27...
Page 92 Technical Reference Microphone/preamplifier combinations Pistonphone Wind noise prevention Microphone Conversion adapter UC-34P NC-74 UA-30 NC-72A UC-27 WS-01 UC-32P NC-73 (discontinued model) UA-10 UC-30 UC-31 UC-33P NC-74 NC-74-002 UA-31 UC-52 NC-72A UC-53A NC-72-S16 UC-57 WS-02 UC-59 NC-73 (discontinued model) NC-71-S02 UA-12 UC-54 WS-05 UA-12...
Page 93 NH-12 2.5 m NH-04 UA-20 NH-12 2.5 m EC-04 2 m EC-04A 5 m NH-17A UA-20 NH-17 5 m EC-04B 10 m NA-42 UA-20 NA-42 SOUND LEVEL MEASURING AMPLIFIER EC-04C 30+5 m LEVEL RANGE UA-20 20dB/50dB EC-04D 50+5 m NH-05...
Page 94: Frequency Range
Technical Reference Measurement range The frequency range and linear operation range depend on the microphone and preamplifi er. Frequency range The frequency range that can be measured depends on the microphone, as shown in the graph below. Microphone UC-24 UC-26 UC-27 UC-28 UC-29...
Page 95: Microphone
Technical Reference Microphone There are various ways to convert sound changes into electrical signals. For acoustic measurements, the condenser (electrostatic) microphone principle is widely used, because it offers high stability, fl at frequency response, high sensitivity and allows compact dimensions. As an example, this manual de- scribes the microphone UC-34.
Page 96 Technical Reference the upper frequency limit means that sensitivity is decreased. The tuning of microphone frequency response is achieved by opening a number of holes in the backplate in order to adjust the viscous resistance (damping characteristics) of the air that moves between the diaphragm and the backplate.
Page 97 Technical Reference The microphone UC-34 is made out of the following materials: titanium (chassis), titanium alloy (diaphragm), and silicone-impregnated and quartz- coated steatite (insulators). The main specifi cations of the microphone are shown in the table below. Main specifi cations of microphone UC-34 Bias voltage 200 V Nominal outer diameter...
Page 98: Preamplifi Er
Technical Reference Preamplifi er Since the capacitance of a condenser microphone is low (in the range of several picofarads to several tens of picofarads), its impedance is very high, especially at low frequencies. In order to achieve usable frequency response down to low frequencies, the load impedance as seen by the microphone must be very high (see equation 1).
Page 99: Insert Cal
Technical Reference Insert CAL By using the dedicated preamplifi er NH-08, the NA-42 allows highly accurate calibration comprising the microphone and preamplifi er (Insert CAL). Insert CAL function The microphone sensitivity is determined under the assumption that the mi- crophone is connected to a preamplifi er with infi nitely large input impedance and input capacitance of 0.
Page 100: Extension Cable
Technical Reference Extension Cable After impedance conversion by the preamplifi er, the signal from the micro- phone is fed through an extension cable to the sound level meter. The fol- lowing extension cables are available as options. Condenser microphone extension cable series EC-04 Model Length Length...
Page 101 Technical Reference 0.1 µF 500 m 40 nF 200 m 20 nF 100 m 10 nF 50 m 4 nF 20 m 2 nF 10 m 1 nF 500 pF 2.5 m 10 k 20 k 50 k 100 k Frequency (Hz) Preamplifier output voltage level (dB (re.
Page 102: Windscreen
Technical Reference Windscreen During outdoor measurements, wind noise can falsify measurement results. To counter such problems, an optional windscreen should be mounted on the microphone. The characteristics of the windscreen WS-01 and WS-02 are shown in the fi gures below and on the next page. The attenuation of wind noise afforded by the windscreen is about 26 dB for sound level (A weighting) and 15 dB for sound level.
Page 103 Technical Reference With WS-02 With WS-01 15 m/s 15 m/s 10 m/s 10 m/s 5 m/s 5 m/s 50 70 100 200 300 600700 1 k 50 70 100 200 300 600700 1 k Frequency (Hz) Frequency (Hz) Frequency response of wind noise measured with windscreen WS-01/WS-02 mounted to microphone With WS-01 20 30 50 70 100...
Page 104: Infl Uence Of Background Noise
Technical Reference Infl uence of Background Noise When measuring a certain sound in a certain location, all other sound present at that location except the measurement target sound are background noise (also called background). Since the sound level meter will display the com- bination of target sound and background noise, the amount of background noise must be taken into consideration when determining the level of the target sound.
Page 105: Frequency Weighting
Technical Reference Frequency Weighting The NA-42 provides a choice between A and C weighting and FLAT fre- quency response. The electrical characteristics of the weighting circuitry are as shown below. FLAT FLAT C weighting C weighting LPF 20 kHz FLAT...
Page 106: Input Connector
Technical Reference INPUT Connector The INPUT connector is a Tajimi Electronics 7-p connector (1008-23A10-7F). The pin assignment is as follows. A: Preamplifi er power supply +12 V / +45 V B: Ground C: Signal input D: Preamplifi er power supply -12 V / -45 V E: 30 V DC / ground / calibration signal INPUT connector as F: 60 V DC (microphone bias voltage)
Page 107: Rms Detection Circuit And Time Weightings
T is performed. The result is divided by T and the square root is extracted. The circuit confi guration for performing the above mathematical operation looks as follows. power of 2 E (rms) Input voltage Output voltage The NA-42 uses digital processing to calculate the rms value.
Page 108 Technical Reference During noise level measurements, the level often fl uctuates drastically, which would make it diffi cult to evaluate readings without some kind of averag- ing. Sound level meters therefore provide the capability for index weighting (index averaging) using the rms circuit. The parameters of this weighting process are called the time weightings, determined by the time constant (see next page).
Page 109 Technical Reference Time weightings and time constant Time constant Time weightings Rise time Fall time FAST 125 ms 125 ms SLOW 35 ms 1.5 s The time weighting circuit of the = CR noise level meter performs index averaging on the square of the sound pressure signal.
Page 110: Factory Default Settings
Technical Reference Factory Default Settings The factory default settings are listed below. To reset the unit to these settings, turn the unit off, and then hold down the RESET key while turning the power on. (The rear-panel PREAMP power selector setting is not reset.) Factory default settings Level range (upper limit) 120 dB...
Page 111: Displaying The Software Version
Technical Reference Displaying the Software Version To display the software version, turn the unit off, and then hold down the MENU (LIGHT) key while turning the power on. The software version is shown in the measurement value fi eld. Version information Software version display example Rack Mounting The unit can be mounted in a rack, using the four screw holes on the bot-...
Page 112: Na-42Pb1
Technical Reference NA-42PB1 The NA-42 Management Software NA-42PB1 is designed for use with the sound level measuring amplifi er NA-42. The software allows setting mea- surement parameters and controlling measurement operation by means of commands sent from the computer. Measurement result data can be read...
Page 113 Technical Reference Main menu screen Measurement screen...
Page 114: Specifi Cations
Specifi cations Measurement functions Sound level L Maximum sound level L Maximum sound level value is held on measurement value readout. Peak sound level L peak Peak sound level value is held on measurement value readout. Sampling frequency 250 kHz Frequency range 1 Hz to 100 kHz (approx.
Page 115 Specifi cations Residual noise Input converted inherent noise A weighting: 1.5 µV rms or less C weighting: 1.5 µV rms or less Flat weighting: 7 µV rms or less Flat (HPF 20 Hz, LPF 20 kHz): 2.5 µV rms or less Linearity range 60 dB Level range switching...
Page 116 Specifi cations Time weighting FAST, SLOW, IMPULSE RMS detection By digital processing Built-in fi lters High-pass fi lter (HPF): 3rd-order Butterworth fi lter, 20 Hz (-3 dB) Low-pass fi lter (LPF): 3rd-order Butterworth fi lter, 20 kHz (-3 dB) Calibration Electrical calibration using 1-kHz sinusoidal wave signal produced by internal oscillator Insert CAL function possible with dedicated preamplifi er NH-08...
Page 117 Specifi cations DC output BNC connector Output voltage: 6 V (at full-scale of range), 1 V/10 dB Output impedance: 50 Ω Load impedance: 10 kΩ or more External fi lter input BNC connector Output impedance: 600 Ω Input impedance: 100 kΩ Serial communication For setting control from computer and data output Connector...
Page 118 Specifi cations Display Backlit LCD Numeric display 5 digits, display range 70 dB second decimal place or fi rst decimal place, switchable Display update interval 1 s for fi rst decimal place readout resolu- tion 0.2 s for second decimal place readout resolution Bar graph Scale range 50 dB or 20 dB, update interval...
Page 119 Specifi cations Power requirements IEC R14 (size "C") batteries × 4 (R14P or LR14) Battery life LR14: approx. 14 hours R14P: approx. 6 hours * Measurement conditions Ambient temperature 23ºC, using microphone UC-53A and preamplifi er NH-17, preamplifi er power supply voltage ±12 V, backlight OFF, serial communication AC adapter NC-98C...
Page 120 Sound calibrator NC-74 Preamplifi er (for vibration measurements) VP-26C NA-42 management software NA-42PB1 (for Microsoft Windows 95, Microsoft Windows 98, Microsoft Windows 98SE, Microsoft Windows Me, Microsoft Windows 2000, Microsoft Windows XP, Microsoft Windows NT (Ver. 4.0) and Microsoft Win-...
Page 121: Dimensional Drawings
Specifi cations SOUND LEVEL NA-42 MEASURING AMPLIFIER LEVEL RANGE 20dB/50dB FAST SENS /SLOW /FLAT /IMP MENU 20Hz 20kHz (LIGHT) INPUT POWER Lp/Lmax /Lpeak RESET EXT FILTER Front BATT BOX AC OUT FILTER LOCK UNLOCK SOUND LEVEL SOUND LEVEL FROM MEASURING AMPLIFIER...
Page 122 No. 32345 13-10...

Rion NA-42 Instruction Manual

1 Electrical Calibration

2 ) Calibration with Pistonphone NC-72A

3 Insert CAL Calibration

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