SIST EN 12668-1:2011

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Zerstörungsfreie Prüfung - Charakterisierung und Verifizierung der Ultraschall-Prüfausrüstung - Teil 1: PrüfgeräteEssais non destructifs - Caractérisation et vérification de l'appareillage de contrôle par ultrasons - Partie 1: AppareilsNon-destructive testing - Characterization and verification of ultrasonic testing equipment - Part 1: Instruments19.100Neporušitveno preskušanjeNon-destructive testingICS:Ta slovenski standard je istoveten z:EN 12668-1:2010SIST EN 12668-1:2011en,fr,de01-februar-2011SIST EN 12668-1:2011SLOVENSKI
STANDARDSIST EN 12668-1:2001/A1:2004SIST EN 12668-1:20011DGRPHãþD

EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 12668-1
February 2010 ICS 19.100 Supersedes EN 12668-1:2000English Version
Non-destructive testing - Characterization and verification of ultrasonic examination equipment - Part 1: Instruments
Essais non destructifs - Caractérisation et vérification de l'appareillage de contrôle par ultrasons - Partie 1 : Appareils
Zerstörungsfreie Prüfung - Charakterisierung und Verifizierung der Ultraschall-Prüfausrüstung - Teil 1: Prüfgeräte This European Standard was approved by CEN on 25 December 2009.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
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B-1000 Brussels © 2010 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 12668-1:2010: ESIST EN 12668-1:2011

Special conditions for ultrasonic instruments with logarithmic amplifiers . 44A.1Introduction . 44A.2Basic requirements. 44A.2.1Measuring accuracy . 44A.2.2Vertical display "linearity" . 44A.3Tests . 44Bibliography . 45 SIST EN 12668-1:2011

According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom.
NOTE This standard uses as limits the points at which the gain is 3 dB below the peak value. 3.3 cross-talk during transmission amount of energy transfer from the transmitter output to the receiver input during the transmission pulse, with the ultrasonic instrument set for dual-element probe (separate transmitter and receiver) 3.4 calibrated dB-switch device controlling the overall gain of the ultrasonic instrument calibrated in decibels 3.5 dead time after transmitter pulse time interval following the start of the transmitter pulse during which the amplifier is unable to respond to incoming signals, when using the pulse echo method, because of saturation by the transmitter pulse 3.6 digitisation sampling error error introduced into the displayed amplitude of an input signal by the periodic nature of measurements taken by an analogue-to-digital converter SIST EN 12668-1:2011

EXAMPLE For an ultrasonic instrument with a maximum gain of 100 dB and a minimum gain of 0 dB, the mid gain position would be 50 dB. 3.18 monitor gate section of the time-base on the A-scan display in which the amplitude is compared to a threshold and/or converted to an analogue output SIST EN 12668-1:2011

TDG time-dependent or swept-gain function fitted to some ultrasonic instruments to correct for the distance-related reduction in reflected amplitude 3.31 short pulse unrectified pulse which has fewer than 1,5 cycles in the time interval over which the pulse amplitude exceeds half its maximum peak amplitude SIST EN 12668-1:2011

Number of measurements taken
nin HzV/ Noise per root bandwidth for receiver input Rl Ω Termination resistor Rmax Ω Input resistance of receiver at maximum gain
Rmin Ω Input resistance of receiver at minimum gain S dB Attenuator setting ∆T s Time increment SIST EN 12668-1:2011

ZA Ω Output impedance of proportional output 5 General requirements for compliance An ultrasonic instrument complies with this standard if it satisfies all of the following conditions: a) the ultrasonic instrument shall comply with Clause 7; b) either a declaration of conformity, issued by a manufacturer operating a certified quality management system, or issued by an organization operating an accredited test laboratory shall be available; NOTE 1 It is recommended that the certification is carried out in accordance with EN ISO 9001, or that the accreditation is carried out in accordance with EN ISO/IEC 17025. c) the ultrasonic instrument shall be clearly marked to identify the manufacturer, type and series, and carry a unique serial number marked on both the chassis and the case; d) a user's instruction manual for the particular type and series of the ultrasonic instrument shall be available; e) a manufacturer's technical specification for the appropriate type and series of ultrasonic instrument which defines the performance criteria in accordance with Clause 6 shall be available. NOTE 2 This specification can form part of the ultrasonic instrument instruction manual or can be separate from it, but it will state the type and series of the ultrasonic instrument to which it applies. The manufacturer's technical specification does not in itself constitute the certificate of measured values required in b). SIST EN 12668-1:2011

EN 12668-1 EN 12668-3 Title of test Manufacturer's tests Periodic and repair tests
Subclause Subclause Subclause Physical state and external aspects 9.2 9.2 3.4.2 Stability
Stability against temperature 8.2
Stability after warm up time 9.3.2 9.3.2
Display jitter 9.3.3 9.3.3
Stability against voltage variation 8.3 9.3.4
Transmitter pulse
Pulse repetition frequency 8.4.2
Effective output impedance 8.4.3
Transmitter pulse frequency spectrum 8.4.4
Transmitter voltage, rise time, reverberation and duration 9.4.2 9.4.2
Receiver
Cross talk damping from transmitter to receiver during transmission 8.5.2
Dead time after transmitter pulse 8.5.3
Dynamic range 8.5.4
Receiver input impedance 8.5.5
Time-dependant gain 8.5.6
Temporal resolution 8.5.7
Amplifier frequency response 9.5.2 9.5.2
Equivalent input noise 9.5.3 9.5.3
EN 12668-1 EN 12668-3 Title of test Manufacturer's tests Periodic and repair tests
Subclause Subclause Subclause Sensitivity and signal-to-noise ratio
3.4.3 Accuracy of calibrated attenuator 9.5.4 9.5.4 3.2.2 Linearity of vertical display 9.5.5 9.5.5 3.2.2 Linearity of equipment gain
3.2.2 Linearity of time-base 9.6 9.6 3.2.1 Monitor gate
Response threshold and switching hysteresis with a fixed monitor threshold 8.6.2
Hold time of switched output 8.6.3
Proportional output
Impedance of proportional output 8.7.1
Linearity of proportional output 8.7.2
Frequency response of proportional gate output 8.7.3
Noise on proportional gate output 8.7.4
Influence of the measurement signal position within the gate 8.7.5
Effect of pulse shape on the proportional gate output 8.7.6
Rise, fall and hold time of proportional gate output 8.7.7
Additional tests for digital ultrasonic instruments Linearity of time-base for digital ultrasonic instruments 8.8.2 8.8.2 3.2.1 Digitisation sampling error 8.8.3
Response time of digital ultrasonic instruments 8.8.4
8 Group 1 tests 8.1 Equipment required for group 1 tests The items of equipment essential to perform group 1 tests on ultrasonic instruments are as follows: a) either: 1) oscilloscope with a minimum bandwidth of 100 MHz and a spectrum analyser with a 40 MHz bandwidth at least; or SIST EN 12668-1:2011

Before connecting the oscilloscope and/or spectrum analyser to the transmitter of the ultrasonic instrument, as required for some of the tests in this standard, check that it will not be damaged by the high transmitter voltage. 8.2 Stability against temperature 8.2.1 Procedure Switch the instrument to separate transmitter/receiver mode. Connect the transmitter output to the first beam of a dual beam oscilloscope and the trigger input of a signal generator (see Figure 1). Connect signal generator gated output to instrument receiver input and also to the second beam of oscilloscope. SIST EN 12668-1:2011

Key 1 ultrasonic instrument 9 gated RF signal generator 2 protection circuit (see Figure 2) 10 external trigger input 3 input 11 RF Output 4 output 12 transmitter output 5 variable attenuator 13 receiver input 6 100 MHz oscilloscope 14 transmitter pulse 7 input channel A 15 test signal 8 input channel B
Figure 1 — Set up for measuring stability against temperature Set the instrument range to 50 mm for a velocity of 5 920 m/s, full rectification. Set the oscilloscope beam 1 to view the instrument transmitter pulse. Set signal generator to generate a burst of three cycles at 2 MHz to 6 MHz with a delay of 10 µs. Set burst amplitude to 1 V peak-to-peak. Adjust oscilloscope beam 2 to view the burst. Now adjust instrument gain control to set the viewed signal to 80 % FSH. The ultrasonic instrument is placed into a climatic chamber (relative humidity between 40 % and 60 %) and subjected to varying ambient temperatures. The signal height and position on the instrument screen shall be read off and recorded at a maximum of 10 °C intervals over the temperature range specified by the manufacturer. SIST EN 12668-1:2011

a) line power over the manufacturers recommended range; and b) variation of battery voltage over the range of voltages which the battery will supply during a full charge and discharge cycle shall be performed. In the case of an instrument which can be powered and operated whilst the battery is charging then the test for variation of line voltage to the charger shall also be performed. If an automatic cut-off system or warning device is fitted, decrease the mains and/or battery voltage and note the signal amplitude at which the cut-off system or warning device operates. Switch the instrument to separate transmitter/receiver mode. Connect the transmitter output to the first beam of a dual beam oscilloscope and the trigger input of a RF signal generator (see Figure 1). Connect signal generator gated output to instrument receiver input and also a second beam of oscilloscope. Set the instrument range to 50 mm for a velocity of 5 920 m/s, full rectification. Set the oscilloscope beam 1 to view the instrument transmitter pulse. Set signal generator to generate a burst of three cycles at 2 MHz to 6 MHz with a delay of 10 µs. Set burst amplitude to 1 V peak-to-peak. Adjust oscilloscope beam 2 to view the burst. Now adjust instrument gain control to set the viewed signal to 80 % FSH. Observe the consistency of amplitude and position on the time base of the reference signal over the ranges defined in the technical specification. 8.3.2 Acceptance criterion The amplitude of the reference signal shall not change by more than ± 5 % and the position shall not change by more than ± 1 %. Operation of automatic cut-off or warning light (if fitted) shall occur before the reference signal amplitude varies by more than ± 2 % of the full screen height or the range changes by more than ± 1 % of the full screen width from the initial setting. 8.4 Transmitter pulse parameters 8.4.1 General This clause contains tests for pulse repetition frequency, output impedance and frequency spectrum. Test methods and acceptance criteria for transmitter pulse shape and amplitude are given in 9.4. SIST EN 12668-1:2011

NOTE Check that the oscilloscope input will not be damaged by the high transmitter voltage. Measure the pulse repetition frequency, using the oscilloscope, at each setting which gives a different pulse repetition frequency. Where more than one combination of controls results in the same pulse repetition frequency (usually the range and pulse repetition frequency) then the pulse repetition frequency only needs to be measured with one of the combinations. For ultrasonic instruments with a continuously adjustable pulse repetition frequency control a setting shall be chosen as given in the manufacturer's technical specification. 8.4.2.2 Acceptance criterion At each setting, the measured value of the pulse repetition frequency shall be within ± 5 % of that given in the technical specification. 8.4.3 Effective output impedance 8.4.3.1 Procedure Using the methods in 9.4.2, measure the transmitter pulse voltage V50 with the transmitter terminated by a 50 Ω non-reactive resistor. Replace the 50 Ω resistor with a 75 Ω resistor and measure, using the oscilloscope, the transmitter pulse voltage V75 with the transmitter terminated by a 75 Ω resistor. The measurement shall be made for each pulse energy setting and transmitter pulse frequency, at maximum and minimum pulse repetition frequencies, with both maximum and minimum damping. For each pulse setting calculate the effective output impedance Zo by means of the following equation: )5075()(755075505075VVVVZo−−×=Ω (1) NOTE Voltages V50 and V75 are the values of the maximum excursions of the respective pulses from the baseline. 8.4.3.2 Acceptance criterion The effective output impedance shall be within ± 5 % of the value in the technical specification and not greater than 50 Ω. 8.4.4 Transmitter pulse frequency spectrum 8.4.4.1 Procedure Measure the frequency spectrum of the transmitter pulse using either a spectrum analyser or an oscilloscope capable of performing Fast Fourier Transforms. The spectrum shall be plotted for at least the 30 dB limits of the frequency response. The pulse settings and the window parameters shall be recorded. The window shall be twice the pulse duration and centred about the pulse. 8.4.4.2 Acceptance criterion The frequency spectrum shall be within the tolerances quoted in the technical specification.
The circuit shown in Figure 2 is used to protect the signal generator from the transmitter spike.
Select each probe frequency setting of the ultrasonic instrument in turn and adjust the signal generator output to be mid-band of the probe frequency setting, adjust signal generator output level to provide maximum level signal on screen as shown in Figure 5. Adjust the amplitude with instrument gain control to make signal half screen height at the maximum range of the screen.
Express the dead time as the time in microseconds (µs) from the zero point to the point on the time base where the amplitude is 25 % screen height (i.e. 50 % of its amplitude at the end of the screen). 8.5.3.2 Acceptance criterion For the worst case frequency band setting, the dead time after the transmitter pulse shall be less than 1 µs. SIST EN 12668-1:2011

If the noise level at the gain setting is higher than 5 % of the screen height, then decrease the gain until the noise level is 5 % of the screen height. Adjust the amplitude of the input signal so that it is displayed at 10 % screen height. Measure (taking due account of the standard attenuator setting) the input voltage amplitude Vmin. The usable dynamic range is given by: dBlog20minmax10VV (3) except where Vmin is less than the input equivalent noise Vein when the dynamic range is limited to: dBlog20max10einVV (4) 8.5.4.2 Acceptance criteria The usable dynamic range shall be at least 100 dB and the minimum input voltage Vmin shall be within the tolerance quoted in the manufacturer's technical specification.
8.5.5 Receiver input impedance 8.5.5.1 Procedure Real and imaginary parts of the receiver input impedance are determined with an impedance analyser with the ultrasonic instrument set for both dual-element probe mode (separate transmitter and receiver) and single transducer probe mode (combined transmitter and receiver). The transmitter pulse should be disabled while measuring the input impedance in single transducer probe mode without disconnecting the receiver from the transmitter. These measurements are to be carried out at a signal frequency of 4 MHz, at the minimum (Rmin, Cmin) and maximum (Rmax, Cmax) gain setting. A damping control, if fitted, should be set to minimum during the test. In general, the input impedance can be sufficiently established by an input resistance and a parallel capacitance. 8.5.5.2 Acceptance criterion At 4 MHz the real part of impedance Rmax at maximum gain shall be greater than or equal to 50 Ω and less than or equal to 1 kΩ. The parallel capacity Cmax shall be less than or equal to 150 pF. The real components of the input impedance at maximum gain Rmax and at minimum gain Rmin shall meet the following condition: SIST EN 12668-1:2011

With the ultrasonic instrument set for dual-element probe mode (separate transmitter and receiver), connect the test equipment as shown in Figure 6. Adjust the gain of the ultrasonic instrument to maximise the dynamic range of the DAC. Throughout this test, avoid saturating the pre-amplifier preceding the DAC circuit. Enable the DAC selected for the test. With the test signal at a position on the horizontal time-base just before the start of the DAC curve, adjust the external standard attenuator so that the amplitude of the test signal is 80 % of screen height and call the standard attenuator setting Ao.
Increase the delay of the test signal to move the test signal along the time-base by ∆T where: NTTT0final−=∆ (7) where
T0 is the time to the start of the DAC curve;
Tfinal is the time to the end of the DAC curve;
N is the number of measurements to be taken; N shall be greater than or equal to eleven. Adjust the standard attenuator to bring the test signal to 80 % of screen height, and record the attenuator setting An. Increase the range of the test signal by increasing the time delay a further ∆T and again record the attenuator setting to bring the test signal to 80 % of screen height. Continue increasing the time delay and adjusting the standard attenuator until N measurements have been made.
After the last measurement, test the DAC for saturation by increasing the external calibrated attenuation by 6 dB and ensuring that the signal is between 38 % to 42 % of screen height. If the signal is not within these limits reduce the range by ∆T and repeat the saturation test. The dynamic range of the DAC is measured at the point where saturation no longer occurs. Plot out the actual DAC curve and the theoretical curve. Repeat the measurement with the centre frequency for each filter setting and for maximum, medium and minimum DAC gain settings. SIST EN 12668-1:2011
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