PCB News - Circuit board manufacturer: specific introduction of ICT hardware structure

Circuit board manufacturer: specific introduction of ICT hardware structure

ICT is the prefix combination of the three English words of information, communication and technology (Information Communications Technology, ICT for short). It is a new concept and new technical field formed by the integration of information technology and communication technology. Also short for online tester.

This article will take the HP3070 circuit board test system as an example to introduce the basic hardware structure of the equipment system in detail.

Overview
The HP3070 circuit test system is mainly used for online testing of PCBA processing boards to determine the quality of analog and digital components on the PCBA board. It can also perform PCB board functional testing, combinational logic testing, analog testing and bidirectional circuit testing. What HP3070 circuit board test system uses is UNIX or MS WINDOWS operating system. The hardware mainly includes test head-Testhead, controller-Controller, power cabinet-Support bay, vacuum box-Cacuum box, and test fixture-Fixture, etc.

Test head
The test head completes the analog test and the digital test. The whole test head can be divided into 2 Banks and 4 and Module. Each Module is fully equipped with 11 cards, that is, there are 11 and card slots. The first card slot is for ASRU card, the sixth card slot is for Control card, and the other card slot is for Pin card. Each Module includes a Mother card, a Control card and ASRU card inserted on the Mother card. And there is at least one Pin card.

Module card: The backplane of the Module, which provides DC power to all cards on the Module, and decodes signals and addresses between cards.

Control card: In the side panel, the program and data are downloaded from the system control to the card, and the sixth slot of the Moudule is controlled according to the program.

Pin card: Provides a multiplexing system during testing. Each dual-density Pin card provides 144 pins for testing. The testing capacity of a Module is 144 times 9, which is 1296 points.

ASRU caed (Analog Stimulate Response Unit): Analog excitation corresponding unit, providing excitation source, vector detector, operational amplifier and other circuit measuring instruments required for simulation test. ASRU card must be in the first slot of each Moudule.

Power supply cabinet
The power cabinet is composed of three parts: power distribution unit-PDU, system card-System card and modular power supply unit-MPU. Programmable DC power supply HP6624 or two other configurations, each HP6624 has four outputs, so it can provide 8 Set the power supply, the power output is connected to the ASRU card in the test head through the cable. The ASRU card has pins to provide the PCB board through the fixture.

PDU: Its main function is to accept the external power supply voltage in the range of 184V~252V, and distribute a variety of volts of AC and DC voltage to other parts of the system. PDU can also realize remote shutdown and voltage limit warning functions. .

System card: The system card is installed on the test head, and the four controllers on the test head communicate with each other. The system card controls whether the PDU and MPU work. The system card can also realize emergency shutdown of all AC power on the test head and the power supply of the power cabinet.

MPU: One MPU unit only provides DC voltage to one test head module, so four MPU units are required. Each MPU unit can provide five voltage values: +20V, +12V, +5V, -10V, -20V.

Controller
The controller is also called the system process unit-SPU, which is actually a microcomputer, which controls the operation of the entire test system. It is equipped with a hard disk drive and a floppy disk drive and runs on the HP-UNIX operating system. The control subsystem has two buses, ALN and GPIB.

LAN: It is a plug-in between the controller and the system card.

GPIB: It is an optional test device that controls the DC power supply and supply of the DUT and the system card.

Test Fixture
The test fixture is a tool for connecting the test head and the PCB board or the power supply under test-DUT. The PCB board can be placed on or off the test fixture automatically or manually. Test fixtures can be divided into long-line fixtures and short-line fixtures.

Long wire fixture: The long wire fixture is a vacuum fixture that uses twisted-pair wires, one is a signal wire connected between the stylus, and the other is a shielded wire connected to the power ground to prevent interference between signals. This fixture is currently used on GenRad.

Disconnection clamp: There are two types of disconnect clamps, one is a vacuum clamp and the other is a magazine clamp. The signal connection in the clamp is very short, which makes the line loss and signal interference smaller and improves the test accuracy. This fixture is currently used on HP3070.