where expertise comes together - since 1996 -

The Largest Open Access Portal of Nondestructive Testing (NDT)

Conference Proceedings, Articles, News, Exhibition, Forum, Network and more

where expertise comes together
- since 1996 -

TecScan Systems
We offer a complete line of NDT scanners, Immersion Tanks & Gantry systems which incorporate Ultrasonic, Phased Array & Eddy Current technologies.
2682 views
Technical Discussions
Pim van Andel
Pim van Andel
04:11 Jun-02-1998
pulse repetition frequency

I am working on the design for electronics of a PC based ultrasonic
instrument.

For manual weld inspection the pulse repetition rate must be rather high
(250Hz?) in view of the probe speed (150mm/sec) and the requirement that
you do not want to miss defect echos. The problem is that a PC screen
can only display A-scans at a rate of e.g. 20 A-scans/sec.

My question: How to reduce 250 Hz prf to 20 A-scans/sec; how is this
solved in digital UT instruments?



 
 Reply 
 
Eugene Suchcicki
Eugene Suchcicki
02:25 Jun-03-1998
Re: pulse repetition frequency
My private( I am not an expert in this field) it would
be to make "average" of let say 25 scans and calculate
one PC screen of information. This "average" could be
inteligent enough to represent miningfull data.
In its simplest form it could be just average.
But having 25 sets of data to be reperented by "one"
event you could for example display such values as
1. min
2. max
3. average
The other alternative is to make the probe movment slower
to match speed( refresh rate) of PC screen. But even so
can anyone spot the problem on the screen if the refresh
rate is high (and probe speed is high). ( Actual information
is on the sceen for fraction of a sec only)
So real time data on the PC screen is of little benefit.
More static screen with recalculated(evaluated)data is what
I would aim for.


: I am working on the design for electronics of a PC based ultrasonic
: instrument.

: For manual weld inspection the pulse repetition rate must be rather high
: (250Hz?) in view of the probe speed (150mm/sec) and the requirement that
: you do not want to miss defect echos. The problem is that a PC screen
: can only display A-scans at a rate of e.g. 20 A-scans/sec.

: My question: How to reduce 250 Hz prf to 20 A-scans/sec; how is this
: solved in digital UT instruments?




 
 Reply 
 
Rainer Meier
R & D
retired from intelligeNDT Systems & Services, Germany, Joined Nov 1998, 15

Rainer Meier

R & D
retired from intelligeNDT Systems & Services,
Germany,
Joined Nov 1998
15
02:46 Jun-03-1998
Re: pulse repetition frequency
: I am working on the design for electronics of a PC based ultrasonic
: instrument.

: For manual weld inspection the pulse repetition rate must be rather high
: (250Hz?) in view of the probe speed (150mm/sec) and the requirement that
: you do not want to miss defect echos. The problem is that a PC screen
: can only display A-scans at a rate of e.g. 20 A-scans/sec.

: My question: How to reduce 250 Hz prf to 20 A-scans/sec; how is this
: solved in digital UT instruments?

For my opinion, it is very important to avoid the suppression of relevant
data. Therefore I would suggest, to show a kind of envelope of the A-scans,
that means to view at each point of time of flight the maximal as well
as the minimal amplitude.
Advandages: - No significant information lost
- You can easily adept your mooving speed to the local
UT-result at your component: The speed is slow enough,
if there is only a small difference bedween minimum
and maximum amplitude.

Rainer Meier


 
 Reply 
 
Linas Svilainis
R & D,
Kaunas University of Technology, Lithuania, Joined Nov 1998, 67

Linas Svilainis

R & D,
Kaunas University of Technology,
Lithuania,
Joined Nov 1998
67
01:18 Jun-03-1998
Re: pulse repetition frequency
: For manual weld inspection the pulse repetition rate must be rather high
: (250Hz?) in view of the probe speed (150mm/sec) and the requirement that
: you do not want to miss defect echos. The problem is that a PC screen
: can only display A-scans at a rate of e.g. 20 A-scans/sec.
The alarm suppose to be automated in order not to miss echoes.

: My question: How to reduce 250 Hz prf to 20 A-scans/sec; how is this
: solved in digital UT instruments?
As already was mentioned, use minimal, maximal,average or trailing envelope
of desired number of A-scans.



 
 Reply 
 
rysiek
rysiek
01:42 Sep-01-1999
Re: pulse repetition frequency
: My private( I am not an expert in this field) it would
: be to make "average" of let say 25 scans and calculate
: one PC screen of information. This "average" could be
: inteligent enough to represent miningfull data.
: In its simplest form it could be just average.
: But having 25 sets of data to be reperented by "one"
: event you could for example display such values as
: 1. min
: 2. max
: 3. average
: The other alternative is to make the probe movment slower
: to match speed( refresh rate) of PC screen. But even so
: can anyone spot the problem on the screen if the refresh
: rate is high (and probe speed is high). ( Actual information
: is on the sceen for fraction of a sec only)
: So real time data on the PC screen is of little benefit.
: More static screen with recalculated(evaluated)data is what
: I would aim for.

:
: : I am working on the design for electronics of a PC based ultrasonic
: : instrument.

: : For manual weld inspection the pulse repetition rate must be rather high
: : (250Hz?) in view of the probe speed (150mm/sec) and the requirement that
: : you do not want to miss defect echos. The problem is that a PC screen
: : can only display A-scans at a rate of e.g. 20 A-scans/sec.

: : My question: How to reduce 250 Hz prf to 20 A-scans/sec; how is this
: : solved in digital UT instruments?
POWODZENIA GIENEK



 
 Reply 
 

Product Spotlight

Cygnus 6+ PRO Multi-Mode Ultrasonic Thickness Gauge

The Cygnus 6+ PRO thickness gauge is the most advance gauge within the Cygnus range with key featu
...
res including: comprehensive data logging; A-scan and B-scan display; manual gain control; Bluetooth connectivity; and much more. With its unique dual display and three measuring modes (Multiple-Echo, Echo-Echo and Single-Echo), this surface thickness gauge offers maximum versatility for inspections.
>

ISAFE3 Intrinsically Safe Sensor System

ISAFE3 intrinsically safe sensor system of Vallen Systeme is especially targeted at the petrochemica
...
l - as well as oil and gas transportation industry. The sensor system is designed for permanent monitoring or periodic inspection tasks. Sensors are available for different AE-frequency ranges optimized for corrosion and fatigue crack detection and other applications. The ISAFE 3 sensor system consists of an AE-sensor (model ISAS3) certified according to ATEX/IEC for installation in zone 0, gas group IIC, IP68, 20 to +60 °C, and a signal isolator (model SISO3) certified for installation in zone 2. An ISAS3 sensor can be mounted in atmosphere or submerged, e.g. in water or crude oil. It is supported by mounting tools for temporary (magnets) or permanent (welded) installation. ISAFE3 supports automatic sensor coupling test and can be used with any AE signal processor supporting 28V supply at 90 mA peak, e.g. Vallen Systeme ASIP-2/A.
>

Echomac® Small

Available with up to eight channels of electronics to detect and evaluate thickness, flaws and eccen
...
tricity, this UT tester is housed in a convenient, smaller cabinet. This instrument can be used in conjunction with bubbler or immersion tank systems, or with a test bench or in laboratory applications. The Echomac® Small is available in the FD4, FD6 or FD6A versions.
>

Silverwing RMS PA - Phased-array corrosion mapping

Eddyfi Technologies integrated two market leading solutions, Silverwing’s RMS and M2M’s instru
...
ments to provide a high-speed, remote access ultrasonic phased-array inspection system with live total focusing method (TFM).
>

Share...
We use technical and analytics cookies to ensure that we will give you the best experience of our website - More Info
Accept
top
this is debug window