PSP

The previous generation of the P-sean ultrasonic inspeetion equipment (based on the PSP-3 P-scan proeessor unit) has been used over a period of 10 years. When a new generation of equipment has to be developed, it is natural to use the experience with the PSP-3 to improve the eoncept in the areas where it has been difficult or impossible to use the PSP-3. 

The system should support all the inspection types available in the PSP-3 P-scan, T-scan and Through Transmission, TOFD and A-scan. It should be possible to record data for all the inspection types simultaneously. The developments in computer hardware, in particular disk storage, during the last years have made it feasable to increase the emphasis on the A-scan recording modes. It has also been feasible to extend the P-scan format to include P-scan image storage in a full 3D format, that allows cross-section views to be generated off-line. 

The P-scan System 4 can be configured in many ways, dependent on the application. Figure 1 shows a basic system configuration. The P-scan processor (PSP-4) controls the scanner and the water pump. Scarmer operation on site is performed from the remote control unit, as an alternative to the control from the computer. The PSP-4 also includes the ultrasonic system. 

The data are transmitted from the front end processor to the computer in digital form over an ethemet link. The data consist of ultrasonic data, either raw RF A-scans or data processed by the digital signal processor in the PSP-4. In addition to the ultrasonic data, scanner coordinates are transmitted over the ethemet link. 

The ethemet connection is combined with the power supply to the PSP-4 and the connected scanner into a single standard cable, that can be used for distances up to 100 m. By using special cables, the distance between the PSP-4 and the eontrol unit can be extended to practieally any distance. 

The PSP-4 includes an interface for scanners, designed for use with the modular scanner concept developed at FORCE Institute. The system supports scanners ranging from simple X-Y scanners to complex scanners, and multi axes robots. 

The unit consists of a mechanical scanner (AWS-6), module of scanner and flaw detector control PSP-3. A standard PC is used for processing the UT results. 

The Master Module (Figure 2, a) controls both the communications in the local network and the communieation between the network and the base station (a Scanner Master Controller or a FORCE Institute PSP-3 or PSP-4 ultrasonic acquisition unit). The communication between the base station and computer (PC with Windows 95 or Unix-workstation) containing the scanner control software runs on a standard ethemet connection. 

For produetion eontrol of small diameter nozzle welds a magnetic wheel scarmer has been build (Figure 4). One standard motor module drives the magnetic wheel and one standard motor module drives the Y-module slide. The two motors are connected to the Master Module. The scanner is controlled from a FORCE Institute PSP-3 ultrasonic acquisition unit with build-in scarmer controller. 

In addition to the controlling computer the system contains only a small control unit - PSP-4 (weight approx. 5 kg.) which among other system components includes a motor control system integrated closely with the PS-4 ultrasonic system. For communication between the PSP-4 control unit and the robot as well as robot power supply is used a single cable less than 10 mm. in diameter. 

G. Hobson, "Neural Network AppHcations at PSP," paper presented at NPRA Computer Conference, Seattie, Wash., 1990. 

Off-diagonal elements of P corresponding to non-bonded atoms can be negative. They arise because P has to satisfy the orthonormality constraint PSP = 4P. They are not assigned any deep physical meaning. 

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