Automatic test equipment
Encyclopedia
Automatic or Automated Test Equipment (ATE) is any apparatus that performs tests on a device, known as the Device Under Test
(DUT), using automation
to quickly perform measurements and evaluate the test results. An ATE can be a simple computer controlled digital multimeter
, or a complicated system containing dozens of complex test instruments (real or simulated electronic test equipment
) capable of automatically testing and diagnosing faults in sophisticated electronic packaged parts or on Wafer testing
, including System-On-Chip
s and Integrated circuit
s.
and the electronic modules in automobiles. It is used in military applications like radar and wireless communication.
s, can test a wide range of electronic devices and systems, from simple components (resistor
s, capacitor
s, and inductor
s) to integrated circuit
s (ICs), printed circuit board
s (PCBs), and complex, completely assembled electronic systems. ATE systems are designed to reduce the amount of test time needed to verify that a particular device works or to quickly find its faults before the part has a chance to be used in a final consumer product. To reduce manufacturing costs and improve yield
, semiconductor devices should to be tested after being fabricated to prevent even a small number of defective devices ending up with consumer.
) that synchronizes one or more source and capture instruments (listed below). Historically, custom-designed controllers or relay
s were used by ATE systems. The Device Under Test (DUT) is physically connected to the ATE by another robotic machine called a Handler
or Prober and through a customized Interface Test Adapter (ITA) or "fixture" that adapts the ATE's resources to the DUT.
is nothing but a normal desktop computer packaged in 19-inch rack standards with sufficient PCI / PCIe slots for accommodating the Signal simulator/sensing cards. This takes up the role of a controller in the ATE. Development of test applications and result storage is managed in this PC. Most modern semiconductor ATEs include multiple computer controlled instruments to source or measure a wide range of parameters. The instruments may include Digital Power Supplies (DPS), Parametric Measurement Units (PMU), Arbitrary Waveform Generators (AWG), Digitizers, Digital IOs, and utility supplies. The instruments perform different measurements on the DUT, and the instruments are synchronized so that they source and measure waveforms at the proper times. Based on the requirement of response-time, real-time systems are also considered for simulation and signal capturing.
is a connector interface between test instruments (PXI, VXI, LXI, GPIB, SCXI, & PCI) and devices/units under test (D/UUT). This section acts as a nodal point for signals going in/out between ATE and D/UUT.
, may not be used in many ATEs due to the limited number of measurements the instrument could make, and the time it would take to use the instruments to make the measurement. One key advantage to using DSP to measure the parameters is time. If we have to calculate the peak voltage of an electrical signal and other parameters of the signal, then we have to employ a peak detector instrument as well as other instruments to test the other parameters. If DSP-based instruments are used, however, then a sample of the signal is made and the other parameters can be computed from the single measurement.
But testing the device for all parameters may or may not be required depending on the device functionality and end user. For example if the device finds application in medical or life saving products then many of its parameters must be tested, and some of the parameters must be guaranteed. But deciding on the parameters to be tested is a complex decision based on cost vs yield
. If the device is a complex digital device, with thousands of gates, then test fault coverage has to be calculated. Here again the decision is complex based on test economics, based on frequency, number and type of I/Os in the device and the end-use application.
is used to bridge the connection between the ITA and the DUT. A socket must survive the rigorous demands of a production floor, so they are usually replaced frequently.
Simple electrical interface diagram: ATE -> ITA -> DUT (package) <- Handler
Simple electrical interface diagram: ATE -> Prober -> Wafer (DUT)
, C++
, Java
, LabVIEW
or Smalltalk
) with additional statements to control the ATE equipment through standard and proprietary Application Programming Interface
s (API). Also some dedicated computer languages exists, like Abbreviated Test Language for All Systems (ATLAS). Automatic test equipment can also be automated using a Test execution engine
such as National Instruments
' TestStand, and Hiatronics' Hiatronic Development Suite.
Sometimes automatic test pattern generation
is used to help design the series of tests.
(STDF)
testing to the ATE system. Diagnostics are often aided by the use of flying probe
testing.
to a test system’s configuration allows for faster, more cost-effective testing of multiple devices, and is designed to reduce both test errors and costs. Designing a test system’s switching configuration requires an understanding of the signals to be switched and the tests to be performed, as well as the switching hardware form factors available.
” or chassis-/mainframe-based systems, often under the control of a custom software application running on an external PC.
The original GPIB standard was developed in the late 1960s by Hewlett-Packard to connect and control the programmable instruments the company manufactured. The introduction of digital controllers and programmable test equipment created a need for a standard, high-speed interface for communication between instruments and controllers from various vendors. In 1975, the IEEE published ANSI/IEEE Standard 488-1975, IEEE Standard Digital Interface for Programmable Instrumentation, which contained the electrical, mechanical, and functional specifications of an interfacing system. This standard was subsequently revised in 1978 (IEEE-488.1) and 1990 (IEEE-488.2). The IEEE 488.2 specification includes the Standard Commands for Programmable Instrumentation (SCPI), which define specific commands that each instrument class must obey. SCPI ensures compatibility and configurability among these instruments.
The IEEE-488 bus has long been popular because it is simple to use and takes advantage of a large selection of programmable instruments and stimuli. Large systems, however, have the following limitations:
LXI instruments sometimes employ scripting using embedded test script processors for configuring test and measurement applications. Script-based instruments provide architectural flexibility, improved performance, and lower cost for many applications. Scripting enhances the benefits of LXI instruments, and LXI offers features that both enable and enhance scripting. Although the current LXI standards for instrumentation do not require that instruments be programmable or implement scripting, several features in the LXI specification anticipate programmable instruments and provide useful functionality that enhances scripting’s capabilities on LXI-compliant instruments.
bus architecture is an open standard platform for automated test based on the VMEbus
. Introduced in 1987, VXI uses all Eurocard form factors and adds trigger lines, a local bus, and other functions suited for measurement applications. VXI systems are based on a mainframe or chassis with up to 13 slots into which various VXI instrument modules can be installed. The chassis also provides all the power supply and cooling requirements for the chassis and the instruments it contains. VXI bus modules are typically 6U
in height.
is a peripheral bus specialized for data acquisition and real-time control systems. Introduced in 1997, PXI uses the CompactPCI 3U
and 6U
form factors and adds trigger lines, a local bus, and other functions suited for measurement applications. PXI hardware and software specifications are developed and maintained by the PXI Systems Alliance. More than 50 manufacturers around the world produce PXI hardware.
, USB is useful for applications in a laboratory setting that do not require a rugged bus connection.
This approach is optimized for small message transfers that are characteristic of test and measurement applications. With very little network overhead and a 100Mbit/sec data rate, it is significantly faster than GPIB and 100BaseT Ethernet in real applications.
The advantage of this platform is that all connected instruments behave as one tightly integrated multi-channel system, so users can scale their test system to fit their required channel counts cost-effectively. A system configured on this type of platform can stand alone as a complete measurement and automation solution, with the master unit controlling sourcing, measuring, pass/fail decisions, test sequence flow control, binning, and the component handler or prober. Support for dedicated trigger lines means that synchronous operations between multiple instruments equipped with onboard Test Script Processors that are linked by this high speed bus can be achieved without the need for additional trigger connections.
Device under test
Device under test , also known as unit under test , is a term commonly used to refer to a manufactured product undergoing testing.-In semiconductor testing:...
(DUT), using automation
Automation
Automation is the use of control systems and information technologies to reduce the need for human work in the production of goods and services. In the scope of industrialization, automation is a step beyond mechanization...
to quickly perform measurements and evaluate the test results. An ATE can be a simple computer controlled digital multimeter
Multimeter
A multimeter or a multitester, also known as a VOM , is an electronic measuring instrument that combines several measurement functions in one unit. A typical multimeter may include features such as the ability to measure voltage, current and resistance...
, or a complicated system containing dozens of complex test instruments (real or simulated electronic test equipment
Electronic test equipment
Electronic test equipment is used to create signals and capture responses from electronic Devices Under Test . In this way, the proper operation of the DUT can be proven or faults in the device can be traced and repaired...
) capable of automatically testing and diagnosing faults in sophisticated electronic packaged parts or on Wafer testing
Wafer testing
Wafer testing is a step performed during semiconductor device fabrication. During this step, performed before a wafer is sent to die preparation, all individual integrated circuits that are present on the wafer are tested for functional defects by applying special test patterns to them. The wafer...
, including System-On-Chip
SOC
SOC or SoC may refer to:Social Networking / Entertainment* Soc.TV, an internet based, social television network* Soldier of ChristBusiness* Sirte Oil Company* South Oil CompanyScience and technology...
s and Integrated circuit
Integrated circuit
An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...
s.
Where ATE is Used
ATE is widely used in the electronic manufacturing industry to test electronic components and systems after being fabricated. ATE is also used to test avionicsAvionics
Avionics are electronic systems used on aircraft, artificial satellites and spacecraft.Avionic systems include communications, navigation, the display and management of multiple systems and the hundreds of systems that are fitted to aircraft to meet individual roles...
and the electronic modules in automobiles. It is used in military applications like radar and wireless communication.
ATE in the Semiconductor Industry
Semiconductor ATE, named for testing semiconductor deviceSemiconductor device
Semiconductor devices are electronic components that exploit the electronic properties of semiconductor materials, principally silicon, germanium, and gallium arsenide, as well as organic semiconductors. Semiconductor devices have replaced thermionic devices in most applications...
s, can test a wide range of electronic devices and systems, from simple components (resistor
Resistor
A linear resistor is a linear, passive two-terminal electrical component that implements electrical resistance as a circuit element.The current through a resistor is in direct proportion to the voltage across the resistor's terminals. Thus, the ratio of the voltage applied across a resistor's...
s, capacitor
Capacitor
A capacitor is a passive two-terminal electrical component used to store energy in an electric field. The forms of practical capacitors vary widely, but all contain at least two electrical conductors separated by a dielectric ; for example, one common construction consists of metal foils separated...
s, and inductor
Inductor
An inductor is a passive two-terminal electrical component used to store energy in a magnetic field. An inductor's ability to store magnetic energy is measured by its inductance, in units of henries...
s) to integrated circuit
Integrated circuit
An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...
s (ICs), printed circuit board
Printed circuit board
A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate. It is also referred to as printed wiring board or etched wiring...
s (PCBs), and complex, completely assembled electronic systems. ATE systems are designed to reduce the amount of test time needed to verify that a particular device works or to quickly find its faults before the part has a chance to be used in a final consumer product. To reduce manufacturing costs and improve yield
Yield
-Physics/chemistry:* Yield , the amount of product obtained in a chemical reaction** The arrow symbol in a chemical equation* Fission product yield* Nuclear weapon yield-Earth science:* Crop yield** Yield...
, semiconductor devices should to be tested after being fabricated to prevent even a small number of defective devices ending up with consumer.
Components of ATE
The Semiconductor ATE architecture consists of master controller (usually a computerComputer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
) that synchronizes one or more source and capture instruments (listed below). Historically, custom-designed controllers or relay
Relay
A relay is an electrically operated switch. Many relays use an electromagnet to operate a switching mechanism mechanically, but other operating principles are also used. Relays are used where it is necessary to control a circuit by a low-power signal , or where several circuits must be controlled...
s were used by ATE systems. The Device Under Test (DUT) is physically connected to the ATE by another robotic machine called a Handler
Handler
- People :* Animal handler, person who conducts animal training or is a wrangler * Handler, a coach, sports agent of a sports player, or entertainer promoter* Agent handler, person who manages a spy...
or Prober and through a customized Interface Test Adapter (ITA) or "fixture" that adapts the ATE's resources to the DUT.
Industrial PC
The Industrial PCIndustrial PC
An Industrial PC is an x86 PC-based computing platform for industrial applications.- History :IBM released the 5531 Industrial Computer in 1984 , arguably the first 'industrial PC'. The IBM 7531, an industrial version of the IBM AT PC was released May 21, 1985. Industrial Computer Source first...
is nothing but a normal desktop computer packaged in 19-inch rack standards with sufficient PCI / PCIe slots for accommodating the Signal simulator/sensing cards. This takes up the role of a controller in the ATE. Development of test applications and result storage is managed in this PC. Most modern semiconductor ATEs include multiple computer controlled instruments to source or measure a wide range of parameters. The instruments may include Digital Power Supplies (DPS), Parametric Measurement Units (PMU), Arbitrary Waveform Generators (AWG), Digitizers, Digital IOs, and utility supplies. The instruments perform different measurements on the DUT, and the instruments are synchronized so that they source and measure waveforms at the proper times. Based on the requirement of response-time, real-time systems are also considered for simulation and signal capturing.
Mass interconnect
The Mass interconnectMass interconnect
Mass interconnect systems act as the connector interface between test instruments and devices/units under test . Used in defense, aerospace, automotive, manufacturing, and other applications....
is a connector interface between test instruments (PXI, VXI, LXI, GPIB, SCXI, & PCI) and devices/units under test (D/UUT). This section acts as a nodal point for signals going in/out between ATE and D/UUT.
Example: Simple Voltage Measurement
For example, to measure a voltage of a particular semiconductor device, the Digital Signal Processing instruments in the ATE measure the voltage directly and send the results to a computer for signal processing, where the desired value is computed. This example shows that conventional instruments, like an AmmeterAmmeter
An ammeter is a measuring instrument used to measure the electric current in a circuit. Electric currents are measured in amperes , hence the name. Instruments used to measure smaller currents, in the milliampere or microampere range, are designated as milliammeters or microammeters...
, may not be used in many ATEs due to the limited number of measurements the instrument could make, and the time it would take to use the instruments to make the measurement. One key advantage to using DSP to measure the parameters is time. If we have to calculate the peak voltage of an electrical signal and other parameters of the signal, then we have to employ a peak detector instrument as well as other instruments to test the other parameters. If DSP-based instruments are used, however, then a sample of the signal is made and the other parameters can be computed from the single measurement.
Test Parameter Requirements vs Test Time
Not all devices are tested equally. Testing adds costs, so low cost components are rarely tested completely, whereas medical or high costs components (where reliability is important) are frequently tested.But testing the device for all parameters may or may not be required depending on the device functionality and end user. For example if the device finds application in medical or life saving products then many of its parameters must be tested, and some of the parameters must be guaranteed. But deciding on the parameters to be tested is a complex decision based on cost vs yield
Yield
-Physics/chemistry:* Yield , the amount of product obtained in a chemical reaction** The arrow symbol in a chemical equation* Fission product yield* Nuclear weapon yield-Earth science:* Crop yield** Yield...
. If the device is a complex digital device, with thousands of gates, then test fault coverage has to be calculated. Here again the decision is complex based on test economics, based on frequency, number and type of I/Os in the device and the end-use application.
Handler or Prober and Device Test Adapter
ATE can be used on packaged parts (typical IC 'chip') or directly on the Silicon Wafer. Packaged parts use a handler to place the device on a customized interface board, whereas silicon wafers are tested directly with high precision probes. The ATE systems interact with the handler or prober to test the DUT.Packaged Part ATE with Handlers
ATE systems typically interface with an automated placement tool, called a "handler", that physically places the Device Under Test (DUT) on an Interface Test Adapter (ITA) so that it can be measured by the equipment. There may also be an Interface Test Adapter (ITA), a device just making electronic connections between the ATE and the Device Under Test (also called Unit Under Test or UUT), but also it might contain an additional circuitry to adapt signals between the ATE and the DUT and has physical facilities to mount the DUT. Finally, a socketJack (connector)
In electronics and electrical assemblies, the term jack commonly refers to a surface-mounted connector, often, but not always, with the female electrical contact or socket, and is the "more fixed" connector of a connector pair...
is used to bridge the connection between the ITA and the DUT. A socket must survive the rigorous demands of a production floor, so they are usually replaced frequently.
Simple electrical interface diagram: ATE -> ITA -> DUT (package) <- Handler
Silicon Wafer ATE with Probers
Wafer based ATEs typically use a device called a Prober that moves across a silicon wafer to test the device.Simple electrical interface diagram: ATE -> Prober -> Wafer (DUT)
Multi-site
One way to improve test time is to test multiple devices at once. ATE systems can now support having multiple "sites" where the ATE resources are shared by each site. Some resources can be used in parallel, others must be serialized to each DUT.Programming ATE
The ATE computer uses modern computer languages (like CC (programming language)
C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....
, C++
C++
C++ is a statically typed, free-form, multi-paradigm, compiled, general-purpose programming language. It is regarded as an intermediate-level language, as it comprises a combination of both high-level and low-level language features. It was developed by Bjarne Stroustrup starting in 1979 at Bell...
, Java
Java (programming language)
Java is a programming language originally developed by James Gosling at Sun Microsystems and released in 1995 as a core component of Sun Microsystems' Java platform. The language derives much of its syntax from C and C++ but has a simpler object model and fewer low-level facilities...
, LabVIEW
LabVIEW
LabVIEW is a system design platform and development environment for a visual programming language from National Instruments. LabVIEW provides engineers and scientists with the tools needed to create and deploy measurement and control systems.The graphical language is named "G"...
or Smalltalk
Smalltalk
Smalltalk is an object-oriented, dynamically typed, reflective programming language. Smalltalk was created as the language to underpin the "new world" of computing exemplified by "human–computer symbiosis." It was designed and created in part for educational use, more so for constructionist...
) with additional statements to control the ATE equipment through standard and proprietary Application Programming Interface
Application programming interface
An application programming interface is a source code based specification intended to be used as an interface by software components to communicate with each other...
s (API). Also some dedicated computer languages exists, like Abbreviated Test Language for All Systems (ATLAS). Automatic test equipment can also be automated using a Test execution engine
Test execution engine
A test execution engine is a type of software used to test software, hardware or complete systems.Synonyms of test execution engine:* Test executive* Test managerA test execution engine may appear in two forms:...
such as National Instruments
National Instruments
National Instruments Corporation, or NI , is an American company with over 5,000 employees and direct operations in 41 countries. Headquartered in Austin, Texas, it is a producer of automated test equipment and virtual instrumentation software...
' TestStand, and Hiatronics' Hiatronic Development Suite.
Sometimes automatic test pattern generation
Automatic test pattern generation
ATPG is an electronic design automation method/technology used to find an input sequence that, when applied to a digital circuit, enables automatic test equipment to distinguish between the correct circuit behavior and the faulty circuit...
is used to help design the series of tests.
Test Data (STDF)
Many ATE platforms used in the semiconductor industry output data using Standard Test Data FormatStandard Test Data Format
Standard Test Data Format is a proprietary file format for semiconductor test information originally developed by Teradyne, but now widely used de facto throughout the semiconductor industry...
(STDF)
ATE Diagnostics
Automatic test equipment diagnostics is the part of an ATE test that determines the faulty components. ATE tests perform two basic functions. The first is to test whether or not the Device Under Test is working correctly. The second is when the DUT is not working correctly, to diagnose the reason. The diagnostic portion can be the most difficult and costly portion of the test. It is typical for ATE to reduce a failure to a cluster or ambiguity group of components. One method to help reduce these ambiguity groups is the addition of analog signature analysisAnalog signature analysis
Analog signature analysis is electronic component and circuit board troubleshooting technique which applies a current-limited AC sinewave across two points of an electronic component or circuit....
testing to the ATE system. Diagnostics are often aided by the use of flying probe
Flying probe
Flying probe test systems are often used for only testing basic production, prototypes, and boards that present accessibility problems. Flying probe testing uses electro-mechanically controlled probes to access components on printed circuit assemblies . Commonly used for test of analog components,...
testing.
Test Equipment Switching
The addition of a high-speed switching systemAutomatic test switching
Automatic test system switching hardware allows for high-speed testing of multiple devices under test, and is designed to reduce both test errors and costs...
to a test system’s configuration allows for faster, more cost-effective testing of multiple devices, and is designed to reduce both test errors and costs. Designing a test system’s switching configuration requires an understanding of the signals to be switched and the tests to be performed, as well as the switching hardware form factors available.
Test Equipment Platforms
Several modular electronic instrumentation platforms are currently in common use for configuring automated electronic test and measurement systems. These systems are widely employed for incoming inspection, quality assurance, and production testing of electronic devices and subassemblies. Industry-standard communication interfaces link signal sources with measurement instruments in “rack-and-stack19-inch rack
A 19-inch rack is a standardized frame or enclosure for mounting multiple equipment modules. Each module has a front panel that is wide, including edges or ears that protrude on each side which allow the module to be fastened to the rack frame with screws.-Overview and history:Equipment designed...
” or chassis-/mainframe-based systems, often under the control of a custom software application running on an external PC.
GPIB/IEEE-488
The General Purpose Interface Bus (GPIB) is an IEEE-488 (a standard created by the Institute of Electrical and Electronics Engineers) standard parallel interface used for attaching sensors and programmable instruments to a computer. GPIB is a digital 8-bit parallel communications interface capable of achieving data transfers of more than 8 Mbytes/s. It allows daisy-chaining up to 14 instruments to a system controller using a 24-pin connector. It is one of the most common I/O interfaces present in instruments and is designed specifically for instrument control applications. The IEEE-488 specifications standardized this bus and defined its electrical, mechanical, and functional specifications, while also defining its basic software communication rules. GPIB works best for applications in industrial settings that require a rugged connection for instrument control.The original GPIB standard was developed in the late 1960s by Hewlett-Packard to connect and control the programmable instruments the company manufactured. The introduction of digital controllers and programmable test equipment created a need for a standard, high-speed interface for communication between instruments and controllers from various vendors. In 1975, the IEEE published ANSI/IEEE Standard 488-1975, IEEE Standard Digital Interface for Programmable Instrumentation, which contained the electrical, mechanical, and functional specifications of an interfacing system. This standard was subsequently revised in 1978 (IEEE-488.1) and 1990 (IEEE-488.2). The IEEE 488.2 specification includes the Standard Commands for Programmable Instrumentation (SCPI), which define specific commands that each instrument class must obey. SCPI ensures compatibility and configurability among these instruments.
The IEEE-488 bus has long been popular because it is simple to use and takes advantage of a large selection of programmable instruments and stimuli. Large systems, however, have the following limitations:
- Driver fanout capacity limits the system to 14 devices plus a controller.
- Cable length limits the controller-device distance to two meters per device or 20 meters total, whichever is less. This imposes transmission problems on systems spread out in a room or on systems that require remote measurements.
- Primary addresses limit the system to 30 devices with primary addresses. Modern instruments rarely use secondary addresses so this puts a 30-device limit on system size.
LAN eXtensions for Instrumentation (LXI)
The LXI Standard defines the communication protocols for instrumentation and data acquisition systems using Ethernet. These systems are based on small, modular instruments, using low-cost, open-standard LAN (Ethernet). LXI-compliant instruments offer the size and integration advantages of modular instruments without the cost and form factor constraints of card-cage architectures. Through the use of Ethernet communications, the LXI Standard allows for flexible packaging, high-speed I/O, and standardized use of LAN connectivity in a broad range of commercial, industrial, aerospace, and military applications. Every LXI-compliant instrument includes an Interchangeable Virtual Instrument (IVI) driver to simplify communication with non-LXI instruments, so LXI-compliant devices can communicate with devices that are not themselves LXI compliant (i.e., instruments that employ GPIB, VXI, PXI, etc.). This simplifies building and operating hybrid configurations of instruments.LXI instruments sometimes employ scripting using embedded test script processors for configuring test and measurement applications. Script-based instruments provide architectural flexibility, improved performance, and lower cost for many applications. Scripting enhances the benefits of LXI instruments, and LXI offers features that both enable and enhance scripting. Although the current LXI standards for instrumentation do not require that instruments be programmable or implement scripting, several features in the LXI specification anticipate programmable instruments and provide useful functionality that enhances scripting’s capabilities on LXI-compliant instruments.
VME eXtensions for Instrumentation (VXI)
The VXIVXI
The VXI bus architecture is an open standard platform for automated test based upon VMEbus. VXI stands for VME eXtensions for Instrumentation, defining additional bus lines for timing and triggering as well as mechanical requirements and standard protocols for configuration, message-based...
bus architecture is an open standard platform for automated test based on the VMEbus
VMEbus
VMEbus is a computer bus standard, originally developed for the Motorola 68000 line of CPUs, but later widely used for many applications and standardized by the IEC as ANSI/IEEE 1014-1987. It is physically based on Eurocard sizes, mechanicals and connectors , but uses its own signalling system,...
. Introduced in 1987, VXI uses all Eurocard form factors and adds trigger lines, a local bus, and other functions suited for measurement applications. VXI systems are based on a mainframe or chassis with up to 13 slots into which various VXI instrument modules can be installed. The chassis also provides all the power supply and cooling requirements for the chassis and the instruments it contains. VXI bus modules are typically 6U
Rack unit
A rack unit or U is a unit of measure used to describe the height of equipment intended for mounting in a 19-inch rack or a 23-inch rack...
in height.
PCI eXtensions for Instrumentation (PXI)
PXIPXI
PCI eXtensions for Instrumentation is one of several modular electronic instrumentation platforms in current use. These platforms are used as a basis for building electronic test equipment, automation systems, modular laboratory instruments in science, and the like. PXI is based on...
is a peripheral bus specialized for data acquisition and real-time control systems. Introduced in 1997, PXI uses the CompactPCI 3U
Rack unit
A rack unit or U is a unit of measure used to describe the height of equipment intended for mounting in a 19-inch rack or a 23-inch rack...
and 6U
Rack unit
A rack unit or U is a unit of measure used to describe the height of equipment intended for mounting in a 19-inch rack or a 23-inch rack...
form factors and adds trigger lines, a local bus, and other functions suited for measurement applications. PXI hardware and software specifications are developed and maintained by the PXI Systems Alliance. More than 50 manufacturers around the world produce PXI hardware.
Universal Serial Bus (USB)
The USB connects peripheral devices, such as keyboards and mice, to PCs. The USB is a Plug and Play bus that can handle up to 127 devices on one port, and has a theoretical maximum throughput of 480 Mbit/s (high-speed USB defined by the USB 2.0 specification). Because USB ports are standard features of PCs, they are a natural evolution of conventional serial port technology. However, it is not widely used in building industrial test and measurement systems for a number of reasons; for example, USB cables are not industrial grade, are noise sensitive, can accidentally become detached, and the maximum distance between the controller and the device is 30 m. Like RS-232RS-232
In telecommunications, RS-232 is the traditional name for a series of standards for serial binary single-ended data and control signals connecting between a DTE and a DCE . It is commonly used in computer serial ports...
, USB is useful for applications in a laboratory setting that do not require a rugged bus connection.
RS-232
RS-232 is a specification for serial communication that is popular in analytical and scientific instruments, as well for controlling peripherals such as printers. Unlike GPIB, with the RS-232 interface, it is possible to connect and control only one device at a time. RS-232 is also a relatively slow interface with typical data rates of less than 20 kbytes/s. RS-232 is best suited for laboratory applications compatible with a slower, less rugged connection.Test Script Processors and a Channel Expansion Bus
One of the most recently developed test system platforms employs instrumentation equipped with onboard test script processors combined with a high-speed bus. In this approach, one “master” instrument runs a test script (a small program) that controls the operation of the various “slave” instruments in the test system, to which it is linked via a high-speed LAN-based trigger synchronization and inter-unit communication bus. Scripting is writing programs in a scripting language to coordinate a sequence of actions.This approach is optimized for small message transfers that are characteristic of test and measurement applications. With very little network overhead and a 100Mbit/sec data rate, it is significantly faster than GPIB and 100BaseT Ethernet in real applications.
The advantage of this platform is that all connected instruments behave as one tightly integrated multi-channel system, so users can scale their test system to fit their required channel counts cost-effectively. A system configured on this type of platform can stand alone as a complete measurement and automation solution, with the master unit controlling sourcing, measuring, pass/fail decisions, test sequence flow control, binning, and the component handler or prober. Support for dedicated trigger lines means that synchronous operations between multiple instruments equipped with onboard Test Script Processors that are linked by this high speed bus can be achieved without the need for additional trigger connections.
See also
- Electronic test equipmentElectronic test equipmentElectronic test equipment is used to create signals and capture responses from electronic Devices Under Test . In this way, the proper operation of the DUT can be proven or faults in the device can be traced and repaired...
- GPIBIEEE-488IEEE-488 is a short-range digital communications bus specification. It was created for use with automated test equipment in the late 1960s, and is still in use for that purpose. IEEE-488 was created as HP-IB , and is commonly called GPIB...
/ IEEE-488IEEE-488IEEE-488 is a short-range digital communications bus specification. It was created for use with automated test equipment in the late 1960s, and is still in use for that purpose. IEEE-488 was created as HP-IB , and is commonly called GPIB... - Semiconductor Test ConsortiumSemiconductor Test ConsortiumThe Semiconductor Test Consortium is a collaborative venture founded with the aim of driving the development of ATE standards throughout the entire test process, enabling ATE peripheral interface standards and encouraging closer working relationships between the semiconductor industry and the ATE...
- VMEbusVMEbusVMEbus is a computer bus standard, originally developed for the Motorola 68000 line of CPUs, but later widely used for many applications and standardized by the IEC as ANSI/IEEE 1014-1987. It is physically based on Eurocard sizes, mechanicals and connectors , but uses its own signalling system,...
- VXIVXIThe VXI bus architecture is an open standard platform for automated test based upon VMEbus. VXI stands for VME eXtensions for Instrumentation, defining additional bus lines for timing and triggering as well as mechanical requirements and standard protocols for configuration, message-based...
- PXIPXIPCI eXtensions for Instrumentation is one of several modular electronic instrumentation platforms in current use. These platforms are used as a basis for building electronic test equipment, automation systems, modular laboratory instruments in science, and the like. PXI is based on...
- LAN eXtensions for Instrumentation
- M-ModuleM-ModuleM-Modules are a mezzanine standard mainly used in industrial computers. Being mezzanines, they are always plugged on a carrier PCB that supports this format...
- Test execution engineTest execution engineA test execution engine is a type of software used to test software, hardware or complete systems.Synonyms of test execution engine:* Test executive* Test managerA test execution engine may appear in two forms:...
External links
- System Integration of an Open-Architecture Test System by Yuhai Ma, Advantest America Inc. (July 2006)
- ATE automatic testing basics
- Impact of Cable Losses Application note defines and details the sources for cable loss in automatic tester systems (ATE).
- GPIB 101A Tutorial About the GPIB Bus ICS Electronics. Retrieved December 29, 2009.
- List of books covering automatic test systems and applications Retrieved July,20 2011.