CASTLE GA112 Manual Download Page 23

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Overall Dimensions and Weight

280x85x60mm
800g with batteries

Accessories available

KA003 Attaché style carry case with tripod*
KA005 Shoulder bag carrying Case
GA607 Dual level acoustic calibrator 94dB and 104dB at 1kHz

*Tripod purchased separately

Summary of Contents for GA112

Page 1: ......

Page 2: ...itself If you would like to become a competent person in the eyes of the law then you may like to know more about our Competent persons training course for the Noise at Work Regulations It is my intention for Castle Group Ltd to provide a complete range of Noise and Vibration products and Services of the highest standard If you would like to know more about any of our other products and services t...

Page 3: ...g and do not pull the cable Clean the unit only by wiping it with a soft dry cloth or when necessary with a cloth lightly moistened with water Do not use any solvents cleaning alcohol or chemical cleaning agents Take care that no conductive objects such as wire metal scraps conductive plastics etc can get into the unit Do not try to disassemble or alter the unit Otherwise type certification will b...

Page 4: ... and Controls 7 Calibration 12 Measuring Sound Levels 13 Measuring Maximum Sound Levels 14 Use of Filters for Octave Band Analysis 15 Use of the Output Socket 16 Instrument Description 18 Circuit Description 19 Environmental Effects 19 Technical Specification 20 Warranty and After Sales Service 24 ...

Page 5: ...IN linear frequency responses as well as a set of ten octave band filters The filter s AUTO facility allows a chart recorder to display the results of a noise spectrum analysis SLOW FAST and PEAK responses are available A maximum hold but ton MAX allows the accurate recording of the maximum rms of a transient noise event The instrument conforms to the relevant sec tions of BS5969 IEC651 ANSIS1 4 B...

Page 6: ...avy duty types which give greater economy and are less prone to leakage to the snap conductors ensuring correct polarity and making sure that each stud is a firm fit Replace the battery cover and push the retaining clip firmly home The instrument is now ready for cali bration and use Remove Cover to c hange Batteries Serial No 012345 Release the spring catch and remove the battery compartment cove...

Page 7: ...th A weighting see figure 1 For a linear or flat frequency response the LIN is used Figure 1 A weighting curve Battery Check Button A push button labelled BATT is provided to allow periodic check ing of the battery condition A meter deflection in the area marked BATT shows the batteries are in good condition A AND LINEAR FREQUENCY WEIGHTINGS 80 70 60 50 40 30 20 10 0 10 10 100 1K 10K Frequency Hz ...

Page 8: ...nce the button is released the meter returns to normal operation This facility is very useful for capturing the maximum rms sound level of tran sient sound events Filter Mode Switch The octave band filters can be used by placing the switch in either the MAN or the AUTO position When in the OUT position the me ter operates as a normal sound level meter with a linear flat or A weighted response When...

Page 9: ...copy of the noise spectrum The fre quency control buttons are assigned different roles in this mode labelled RESET and START STOP Depressing the RESET button at any time causes the filter frequency to reset to the lowest centre frequency 31 5Hz By depressing the START STOP button once the filter will step up through all the fre quencies in turn staying on each frequency for 3 to 4 seconds This all...

Page 10: ...ar row is depressed The five base ranges on the GA112 are shown be low figure 3 Figure 3 Table of available ranges As can be seen from the table above a 10dB overlap occurs between the ranges this means that if a meter reading in the bottom third is observed the range can be changed down Generally it is better to select a range which gives you the greatest deflection on the meter However if the me...

Page 11: ...rs and similar equipment A 3 pin LEMO connector type FGGOB303CLAD52Z must be used to connect external equipment Overload LED This indication is on the meter scale and warns when the selected range is exceeded In such an overload situation frequency analysis is distorted as the signal is clipped Generally this can be avoided be choosing a higher range Please note the overload indicator detects the ...

Page 12: ...ator manual A 1kHz tone should be audible at this time 4 Position the calibrator firmly over the microphone using a clockwise twist 5 Place the meter on its 70dB range and adjust the CAL control until the meter reads 94dB 6 If using the Castle GA607 calibrator it is also possible to check the sound level meter on its 90dB range switch the calibrator to the 104dB position and check that the reading...

Page 13: ...the sound level meter 3 Select the 110dB range 4 Point the instrument towards the source of the sound to be measured 5 Progressively step down the ranges until a reading in the upper two thirds of the meter scale is obtained 6 If it proves difficult to read the meter because of excessive or unsteady needle movement switch the response to SLOW 7 Record the sound level reading as the meter deflectio...

Page 14: ...on the meter without causing it to go off the scale By trying several ranges the most suitable will soon be found 4 Set the response switch to FAST or PEAK 5 Point the instrument towards the source of the sound to be measured 6 Press the MAX button and hold it down until the transient sound has occurred and the meter has reached its maximum value The button must be held until the reading has been ...

Page 15: ... step down the ranges until a reading in the upper two thirds of the meter scale is obtained 6 Record the reading and select the next centre frequency Repeat the measuring procedure until the highest filter frequency 16kHz is reached It is possible to switch the filter OUT and back to MAN again and still maintain the last selected centre frequency 7 With the results obtained an octave band plot ca...

Page 16: ... for recording the noise by means of a tape recorder for analysis at a later date A full scale deflection on the meter corresponds to a 120mV rms signal into a 10kohm loading The DC output is a linear signal suitable for chart recorders A volt age of 1 5V is given for a full scale deflection on the meter zero on the meter corresponds to approximately zero volts The DC output is designed to drive a...

Page 17: ... change of frequency 5 When the filter has reached the top 16kHz frequency it will remain there To repeat the procedure depress the RESET button in order to start from 31 5Hz fre quency again Pressing the START STOP button during the stepping procedure will STOP the filter on its current centre frequency pressing the button once more will START the stepping once more The START STOP button therefor...

Page 18: ...PLAY FREQUENCY SELECT A WEIGHTING amp AC OUTPUT OVERLOAD DETECTOR OVERLOAD LED amp SLOW FAST PEAK BATTERY CHECK MAX HOLD DC OUTPUT amp METER PRECISION RMS TO LOG DC CONVERTER amp amp CALIBRATION RANGE CONTROL LED DISPLAY FILTER OFF MAN AUTO Instrument Description 18 ...

Page 19: ...equency changing logic selects the filter fre quency and displays it by way of LED s This signal is passed to the true rms converter and logged This is then converted to a linear signal in order to drive the meter which is linearly scaled in dB A maximum hold facility is used to maintain the maxi mum meter deflection while readings are being taken and a battery check facility also drives the meter...

Page 20: ... weighting Slow to BS EN 60651 Type 1 Fast to BS EN 60651 Type 1 Peak Onset time 2 3mS as specified by BS EN 60651 Display Type Analogue moving coil meter with overload LED indication Scale 0 to 30dB mirrored linear scale with battery condition indication and overload indication Range Measuring Range Max Peak Level 30 30 60dB 73dB 50 50 80d B 93dB 70 70 100dB 113dB 90 90 120dB 133dB 110 110 140dB ...

Page 21: ...UTO Overload Positive overload condition shown when Crest Factor is exceeded see also description on page 11 Output Socket AC Output 120mV rms for FSD Output impedance approx 600ohm Load impedance 10kohm or more Short circuit protected DC Output 1 5V for FSD Output impedance approx 600ohm Load impedance 10kohm or more Short circuit protected Connector Lemo FGG0B303CLAD52Z Microphone Preamp Pre pol...

Page 22: ...s Temperature Operating range 10oC to 50oC Storage without batteries 20oC to 70oC Effect of temperature 0 5dB from 10oC to 50oC Humidity Operating range 30 RH to 90 RH Effect of humidity 0 5dB Vibration A 40Hz 1m s vibrating force produces 0 5dB error Magnetic field 80A m 1 Oersted at 50Hz produces 0 5dB error Standards BSEN60651 IEC651 Type1 BS5969 Type 1 22 ...

Page 23: ...eight 280x85x60mm 800g with batteries Accessories available KA003 Attaché style carry case with tripod KA005 Shoulder bag carrying Case GA607 Dual level acoustic calibrator 94dB and 104dB at 1kHz Tripod purchased separately 23 ...

Page 24: ...ts are designed to meet rigid British and International Standards An annual calibration is recommended to ensure that these high standards are maintained This is particularly important for cases in which instrument readings are to be used in litigation or compliance work For warranty and service return to The Service Department Castle Group Ltd Salter Road Cayton Low Road Industrial Estate Scarbor...

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