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Ultrasonic devices are digitalised, so it is almost impossible to find an analogue device

on the market. These are the devices of significant capacity in programming. When the

sound velocity, distance range and detection sensitivity are known the device can be set

by only one referent reflector. DGSreference curve can be directly downloaded from the

memory, and a digital-to-analogue converter (DA) curve can be saved in the memory and

called in testing procedure.

Modern devices for eddy current testing, for acoustic emission testing and visual

control are also digitalised. In the videoscope is the chipis applied at the tip of the sensor,

and the signal is digitalised in the control unit connecting video chart and monitor.

2.2. Calibration of the equipment

Being the measuring devices the NDT equipment has to be

the standard

does not prescribe calibration intervals, then the equipment user has to do this. The equip-

ment and devices are to be calibrated in national institution for measures, at equipment

producers or in non-destructive testing laboratory, following the accepted procedure.

High voltage in x-ray equipment is to be checked using one of three procedures

accepted in European Standards and the focal (point) following one of five prescribed

procedures. The amperage of the tube and exposition time can be checked by the NDT

laboratory itself.

The dimensions of the isotope are to be checked by x-ray method.

For the illuminator light diffusion, illumination uniformity and screen temperature are

to be checked.

According to ASME, Sec. V, Part. 2, densitometer should be calibrated every 90 days

using gradually darkened bands traceable to NIST.

For ultrasonic devices and testing sensors European Standards prescribed checking of

series of parameters, what can be performed in general only at device producer. Non-

destructive testing companies have to check by them own

- Daily: index of a head,beam angle, physical state and outer aspects,

-Weekly:time base linearity,amplification linearity,sensitivity and the relation signal

noise, impulse duration.

Working characteristic (relationship voltagevs. amperage) and ampermeter accuracy

have to be checked in current sources for testing by magnetic particles.

Electrical magnetic yoke is to be checked by the test of lifting plateof specified mass

or measuring tangential field capacity in the middle of poles distance.

All instruments for measurement of testing parameters have to be calibrated as well, as

this the case with UV meter, instrument for measurement of magnetic tangential field

capacity, thermometer, chronometer, manometer.

2.3. Testing media

Testing media (suspension of magnetic particles and components of dye penetrant sys-

tem have to pass specified testing and testing of each batch. Batch testing certificate must

be enclosed todelivered material; certificate of specified testing should be requested.

2.4, Documentation requested before testing

Testing bidder in stage of ordering should supply to tester a row of data about tested

subject, among other the requested quality level of the tested subject, preferably in the

specificationform, for examplefor welding joint EN ISO 5817 quality level C, for