DAQ Application: Non-Destructive Testing | GaGe

Industrial Application Case Study - Data Acquisition Non-Destructive Testing

Industrial Applications

Non-Destructive Testing (NDT)

Customer Case

This customer manufactures non-destructive test equipment which allows customers such as steel mills to test the quality of their end-products.

Presently, the ultrasound frequencies being used are centered at either 5 MHz, 10 MHz or 15 MHz. The worst case analog bandwidth requirement in this case is 35 MHz. In order to set up their equipment properly, the customer presently views the return signal (including the flaw) on an analog oscilloscope with a sweep time of either 50 us or 100 us (providing approximately 5 to 10 inches of depth in a metal). The flaw signal appears as a faint signal on the scope display due to its low duty cycle.

The signal is coming out of the NDT tester, which is based on a rotary motor running at 1800 rpm (30 Hz). There may be more than one or two signals that the customer needs to view.

The customer wants to move from an analog oscilloscope to a more digital system. An accuracy of 1% is more than enough for the application. Therefore, an 8-bit digitizer will be sufficient.

Quantity requirements will be approximately 10 to 12 boards a year, as this card will go into each of the machines built.

GaGe Case Solution

Digital Storage Oscilloscopes (DSOs) were originally considered as an option. They were, however, dismissed as impractical because they are "off-line" more often than "on-line," as they have to offload data at very slow transfer rates. In this application the customer cannot afford to miss the trigger events, as any one of them may contain the "flaw" that they are most interested in.

The ideal solution for this application is to use the CompuScope 265-a 130 MSPS A/D and scope card for the PC.

With a sweep time of 50 us and a sample rate of 130 MSPS (7.6 ns per point), each acquisition will be 50,000 / 7.69 = 6,500 points per trigger. To acquire 100 consecutive triggers, the customer will need a CompuScope 265 with 1 Meg of on-board memory, i.e. CompuScope 265-1M.

The customer will acquire these 100 successive triggers in MULTIPLE RECORD mode, i.e. for each trigger the CompuScope 265 will acquire 6,500 points (this value is controlled by software) and stack in on-board memory. Once enough data has been captured, software can read the data and display it accordingly (most probably overlay all acquisitions).

It should be pointed out that once the data has been captured, our software drivers bring that data into an array which the customer's program allocates. In other words, their software programmers do not have to deal with the "bits and bytes" on the CompuScope 265 board.

The customer also mentioned that it may be beneficial for them to write a customized display software for this data because:

  • They need customized display routines which can show the flaw more clearly. Their engineers will be able to write these routines in a C or BASIC program.
  • They may need to analyze the shape of the flaw in order to get more information on the nature of the flaw.
  • They want to have a display with their company's name and logo on the screen instead of the name of the oscilloscope manufacturer.

They also mentioned that most of their current software development efforts at the company are in DOS, but they may want to switch to Windows. GaGe provides software drivers for Windows. We also provide customers with source code of sample programs which show exactly how to use the drivers-many customers are able to get boards running under their software control within days of receiving the product from GaGe.

As a potential OEM, this customer will also qualify for the very solid software support provided by GaGe's Software Engineering department during their development and integration phase. This support is invaluable, as it can save months of software development time.

GaGe Case Recommended Products

  • CompuScope 265-1M - 8-bit, 130 MSPS A/D Card for ISA Bus with 1 Msample Memory Depth

Industrial Application Request

We encourage you to contact us and discuss your industrial application in more detail with our engineering team. GaGe can provide tailored custom data acquisition hardware and software solutions to meet specific application requirements.