IEEE 488 , also known as HP-IB ( Hewlett-Packard Interface Bus ) and generically as GPIB ( General Purpose Interface Bus ), is a short-range digital communications 8-bit parallel multi-master interface bus specification developed by Hewlett-Packard . It subsequently became the subject of several standards.
65-564: Although the bus was created in the late 1960s to connect together automated test equipment , it also had some success during the 1970s and 1980s as a peripheral bus for early microcomputers , notably the Commodore PET . Newer standards have largely replaced IEEE 488 for computer use, but it is still used by test equipment. In the 1960s, Hewlett-Packard (HP) manufactured various automated test and measurement instruments, such as digital multimeters and logic analyzers . They developed
130-519: A computer ) that synchronizes one or more source and capture instruments (listed below). Historically, custom-designed controllers or relays 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. The industrial PC
195-473: 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
260-416: A "talker" and one or more devices as "listeners" without having to participate in the data transfer. It is possible for multiple controllers to share the same bus, but only one can be the "Controller In Charge" at a time. In the original protocol, transfers use an interlocked, three-wire ready–valid–accepted handshake. The maximum data rate is about one megabyte per second. The later HS-488 extension relaxes
325-726: A French manufacturer of connectors and interconnect systems based in Thyez , was acquired by Amphenol. The company manufactures D38999 connectors and is well established in the defense and aerospace markets. In May 2005, Amphenol acquired SV Microwave , a manufacturer of RF connectors, components and cable assemblies. On October 10, 2005, Teradyne and Amphenol announced that Amphenol would acquire Teradyne Connection Systems, for about USD $ 390 million in cash. TCS, based in Nashua , New Hampshire , manufactures high-density electronic connectors , complete backplanes , and systems packaging,
390-470: A French manufacturer of power busbars and power interconnect solutions. In January 2017, Amphenol acquired Phitek Ltd, a New Zealand-based manufacturer and the world's leading supplier of electronic noise-cancellation, audio enhancement and other electronic touch point devices in the aircraft cabin. In June 2017, Amphenol acquired Wilcoxon Research (US), Piezo Technologies (US) and Piher Sensors and Controls (Spain), three Industrial Sensing businesses from
455-495: A backward-compatible extension to IEEE 488.1, originally known as HS-488. It increased the maximum data rate to 8 Mbyte /s, although the rate decreases as more devices are connected to the bus. This was incorporated into the standard in 2003 (IEEE 488.1-2003), over HP's objections. In 2004, the IEEE and IEC combined their respective standards into a "Dual Logo" IEEE/IEC standard IEC 60488-1, Standard for Higher Performance Protocol for
520-561: A business started by Raj Khanijow based in Huntsville AL. Tecvox is a leader in automotive OEM USB connectivity products. Tecvox was the first automotive company to release the OEM USB based media hub and charger. On January 8, 2016, Amphenol finalized its deal to acquire FCI Asia Pte Ltd an interconnect company specializing in the telecom, datacom and wireless communications markets. In July 2016, Amphenol acquired AUXELFTG (AUXEL),
585-549: A cartridge for the C64 that provided an IEEE 488-derived interface on a card edge connector similar to that of the PET series. Eventually, faster, more complete standards such as SCSI superseded IEEE 488 for peripheral access. Electrically, IEEE 488 used a hardware interface that could be implemented with some discrete logic or with a microcontroller. The hardware interface enabled devices made by different manufacturers to communicate with
650-439: 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-232 , USB is useful for applications in a laboratory setting that do not require
715-502: A nodal point for signals going in/out between ATE and D/UUT. For example, to measure a voltage of a particular semiconductor device, the Digital Signal Processing (DSP) 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 ammeter , may not be used in many ATEs due to
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#1732779547286780-494: A product line that complements Amphenol's existing lines of business. In February 2008, Amphenol acquired SEFEE , a French electronic manufacturer, the next year in 2009 it acquired Jaybeam Wireless . Jaybeam Wireless became Amphenol Jaybeam and is now Amphenol Antenna Solutions. On November 15, 2013, Amphenol announced it had entered an agreement to acquire Advanced Sensors Business of GE for approx. $ 318 million. In December 2013, Amphenol acquired Tecvox OEM Solutions LLC,
845-507: A rugged bus connection. 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 KB/s. RS-232 is best suited for laboratory applications compatible with
910-410: 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,
975-447: A sample of the signal is made and the other parameters can be computed from the single measurement. 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
1040-466: A single host. Since each device generated the asynchronous handshaking signals required by the bus protocol, slow and fast devices could be mixed on one bus. The data transfer is relatively slow, so transmission line issues such as impedance matching and line termination are ignored. There was no requirement for galvanic isolation between the bus and devices, which created the possibility of ground loops causing extra noise and loss of data. Physically,
1105-447: A slower, less rugged connection. It works on a ±24 volt supply. Boundary scan can be implemented as a PCB-level or system-level interface bus for the purpose of controlling the pins of an IC and facilitating continuity (interconnection) tests on a test target (UUT) and also functional cluster tests on logic devices or groups of devices. It can also be used as a controlling interface for other instrumentation that can be embedded into
1170-428: 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
1235-421: A unique address to each device on the bus. The standard allows up to 15 devices to share a single physical bus of up to 20 metres (66 ft) total cable length. The physical topology can be linear or star (forked). Active extenders allow longer buses, with up to 31 devices theoretically possible on a logical bus. Control and data transfer functions are logically separated; a controller can address one device as
1300-889: Is a fiber optic company started in 1993 that specializes in the fabrication and manufacturing of fiber optic connectivity products and systems. AFSI provides solutions for communication systems based on fiber optic interconnect technology. AFSI employs over 100 people at its 50,000 square foot facility in the heart of the telecom corridor in Allen, just north of Dallas, Texas. Amphenol Cables on Demand, another division of Amphenol launched in December 2006, specializes in distributing standard cable assemblies via their e-commerce storefront. They sell more than 2500 audio, video, computer, and networking cables. Offices are located in New York, California, Florida, Toronto, and China. In 1986, Socapex ,
1365-689: Is a normal desktop computer packaged in 19-inch rack standards with sufficient PCI / PCIe slots for accommodating the Signal stimulator/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 device power supplies (DPS), parametric measurement units (PMU), arbitrary waveform generators (AWG), digitizers, digital IOs, and utility supplies. The instruments perform different measurements on
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#17327795472861430-492: Is an American producer of electronic and fiber optic connectors, cable and interconnect systems such as coaxial cables . Amphenol is a portmanteau from the corporation's original name, American Phenolic Corp. Amphenol was founded in Chicago in 1932 by entrepreneur Arthur J. Schmitt , whose first product was a tube socket for radio tubes (valveholder bases). Amphenol expanded significantly during World War II , when
1495-476: 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
1560-699: 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. 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-stack " or chassis-/mainframe-based systems, often under
1625-408: 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
1690-409: Is simple to use and takes advantage of a large selection of programmable instruments and stimuli. Large systems, however, have the following limitations: 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
1755-462: Is they commonly use a "double-headed" design, with male on one side, and female on the other. This allows stacking connectors for easy daisy-chaining . Mechanical considerations limit the number of stacked connectors to four or fewer, although a workaround involving physically supporting the connectors may be able to get around this. They are held in place by screws, either 6-32 UNK (now largely obsolete) or metric M3.5×0.6 threads . Early versions of
1820-660: Is widely used in the electronic manufacturing industry to test electronic components and systems after being fabricated. ATE is also used to test avionics and the electronic modules in automobiles. It is used in military applications like radar and wireless communication. Semiconductor ATE, named for testing semiconductor devices , can test a wide range of electronic devices and systems, from simple components ( resistors , capacitors , and inductors ) to integrated circuits (ICs), printed circuit boards (PCBs), and complex, completely assembled electronic systems. For this purpose, probe cards are used. ATE systems are designed to reduce
1885-523: The HP Interface Bus (HP-IB) to enable easier interconnection between instruments and controllers (computers and other instruments). This part of HP was later (c. 1999) spun off as Agilent Technologies , and in 2014 Agilent's test and measurement division was spun off as Keysight Technologies . The bus was relatively easy to implement using the technology at the time, using a simple parallel bus and several individual control lines. For example,
1950-633: The HP Series 80 , HP 9800 series , the HP 2100 series, and the HP 3000 series. HP computer peripherals which did not utilize the RS-232 communication interface often used HP-IB including disc systems like the HP 7935 . Some of HP's advanced pocket calculators of the 1980s, such as the HP-41 and HP-71B series, also had IEEE 488 capabilities, via an optional HP-IL /HP-IB interface module. Other manufacturers adopted GPIB for their computers as well, such as with
2015-599: The Tektronix 405x line. The Commodore PET (introduced 1977) range of personal computers connected their peripherals using the IEEE 488 bus, but with a non-standard card edge connector. Commodore's following 8-bit machines utilized a serial bus whose protocol was based on IEEE 488. Commodore marketed an IEEE 488 cartridge for the VIC-20 and the Commodore 64. Several third party suppliers of Commodore 64 peripherals made
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2080-533: The device under test (DUT), equipment under test (EUT) or unit under test (UUT), 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 chips and integrated circuits . ATE
2145-423: The ATE equipment through standard and proprietary application programming interfaces (API). Also some dedicated computer languages exist, like Abbreviated Test Language for All Systems (ATLAS). Automatic test equipment can also be automated using a test execution engine such as NI 's TestStand. Sometimes automatic test pattern generation is used to help design the series of tests. Many ATE platforms used in
2210-468: The DUT and has physical facilities to mount the DUT. Finally, a socket 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 Wafer-based ATEs typically use a device called a prober that moves across a silicon wafer to test
2275-401: 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 stimulation and signal capturing. The mass interconnect is a connector interface between test instruments (PXI, VXI, LXI, GPIB, SCXI, & PCI) and devices/units under test (D/UUT). This section acts as
2340-648: The HP 59501 Power Supply Programmer and HP 59306A Relay Actuator were both relatively simple HP-IB peripherals implemented in TTL , without the need for a microprocessor. HP licensed the HP-IB patents for a nominal fee to other manufacturers. It became known as the General Purpose Interface Bus (GPIB), and became a de facto standard for automated and industrial instrument control. As GPIB became popular, it
2405-458: The ICs themselves (see IEEE 1687) or instruments that are part of an external controllable test system. 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
2470-458: The IEEE 488 connectors and cabling were rugged and held in place by screws. While physically large and sturdy connectors were an advantage in industrial or laboratory set ups, the size and cost of the connectors was a liability in applications such as personal computers. Although the electrical and physical interfaces were well defined, there was not an initial standard command set. Devices from different manufacturers might use different commands for
2535-658: 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
2600-535: The PXI Systems Alliance. More than 50 manufacturers around the world produce PXI hardware. USB connects peripheral devices, such as keyboards and mice, to PCs. 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
2665-613: The Standard Digital Interface for Programmable Instrumentation - Part 1: General , replaces IEEE 488.1/IEC 60625-1, and IEC 60488-2, Part 2: Codes, Formats, Protocols and Common Commands , replaces IEEE 488.2/IEC 60625-2. IEEE 488 is an 8-bit , electrically parallel bus which employs sixteen signal lines — eight used for bi-directional data transfer, three for handshake , and five for bus management — plus eight ground return lines. The bus supports 31 five-bit primary device addresses numbered from 0 to 30, allocating
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2730-415: 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 be tested after being fabricated to prevent defective devices ending up with the consumer. The semiconductor ATE architecture consists of master controller (usually
2795-482: 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. The VXI bus architecture
2860-479: The chassis and the instruments it contains. VXI bus modules are typically 6U in height. PXI 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
2925-452: The company became the primary manufacturer of connectors used in military hardware, including airplanes and radios. From 1967 to 1982 it was part of Bunker Ramo Corporation . The company sells its products into diverse electronics markets, including military-aerospace, industrial, automotive, information technology, mobile phones, wireless infrastructure, broadband, medical, and pro audio. Operations are located in more than 60 locations around
2990-405: The connectors and cabling that could be used with serial data transfer standards such as RS-232 , RS-485 , USB, FireWire or Ethernet. Very few mass-market personal computers or peripherals (such as printers or scanners) implemented IEEE 488. Automated test equipment Automatic test equipment or automated test equipment ( ATE ) is any apparatus that performs tests on a device, known as
3055-535: The control of a custom software application running on an external PC. 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 MB/s. It allows daisy-chaining up to 14 instruments to
3120-430: The device and the end-use application... 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. ATE systems typically interface with an automated placement tool, called
3185-467: 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
3250-482: The device. Simple electrical interface diagram: ATE → Prober → Wafer (DUT) 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. The ATE computer uses modern computer languages (like C , C++ , Java , VEE , Python , LabVIEW or Smalltalk ) with additional statements to control
3315-430: The established 24-pin connector. HP's designers did not specifically plan for IEEE 488 to be a peripheral interface for general-purpose computers; the focus was on instrumentation. But when HP's early microcomputers needed an interface for peripherals ( disk drives , tape drives , printers , plotters , etc.), HP-IB was readily available and easily adapted to the purpose. HP computer products which used HP-IB included
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#17327795472863380-450: The format of commands or data. In 1987, IEEE introduced Standard Codes, Formats, Protocols, and Common Commands , IEEE 488.2. It was revised in 1992. IEEE 488.2 provided for basic syntax and format conventions, as well as device-independent commands, data structures, error protocols, and the like. IEEE 488.2 built on IEEE 488.1 without superseding it; equipment can conform to IEEE 488.1 without following IEEE 488.2. While IEEE 488.1 defined
3445-525: The handshake requirements, allowing up to 8 Mbyte/s. The slowest participating device determines the speed of the bus. IEEE 488 specifies a 24-pin Amphenol -designed micro ribbon connector. Micro ribbon connectors have a D-shaped metal shell, but are larger than D-subminiature connectors. They are sometimes called "Centronics connectors" after the 36-pin micro ribbon connector Centronics used for their printers. One unusual feature of IEEE 488 connectors
3510-430: The hardware and IEEE 488.2 defined the protocol, there was still no standard for instrument-specific commands. Commands to control the same class of instrument, e.g. , multimeters, varied between manufacturers and even models. The United States Air Force, and later Hewlett-Packard, recognized this as a problem. In 1989, HP developed their Test Measurement Language (TML) or Test and Measurement Systems Language (TMSL) which
3575-461: 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
3640-438: 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. Amphenol Amphenol Corporation
3705-483: 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 analysis testing to the ATE system. Diagnostics are often aided by the use of flying probe testing. The addition of a high-speed switching system to a test system's configuration allows for faster, more cost-effective testing of multiple devices, and
3770-564: The same function. Some aspects of the command protocol standards were not standardized until Standard Commands for Programmable Instruments (SCPI) in 1990. Implementation options (e.g. end of transmission handling) can complicate interoperability in pre-IEEE 488.2 devices. More recent standards such as USB , FireWire , and Ethernet take advantage of declining costs of interface electronics to implement more complex standards providing higher bandwidth. The multi-conductor (parallel data) connectors and shielded cable were inherently more costly than
3835-410: The semiconductor industry output data using Standard Test Data Format (STDF) 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
3900-1062: 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
3965-509: The standard suggested that metric screws should be blackened to avoid confusion with the incompatible UTS threads. However, by the 1987 revision this was no longer considered necessary because of the prevalence of metric threads. The IEC 60625 standard prescribes the use of 25-pin D-subminiature connectors (the same as used for the parallel port on IBM PC compatibles ). This connector did not gain significant market acceptance against
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#17327795472864030-405: 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 100 Mbit/sec data rate, it
4095-577: The world. Amphenol's world headquarters is located in Wallingford, Connecticut . The largest division of Amphenol is Amphenol Aerospace (formerly Bendix Corporation ) in Sidney , New York . This is the birthplace of the MIL-DTL-38999 cylindrical connector. Amphenol engineers also invented the commonly used BNC connector ("Bayonet Neill-Concelman"). Amphenol Fiber Systems International
4160-472: Was formalized by various standards organizations . In 1975, the IEEE standardized the bus as Standard Digital Interface for Programmable Instrumentation , IEEE 488; it was revised in 1978 (producing IEEE 488-1978). The standard was revised in 1987, and redesignated as IEEE 488.1 (IEEE 488.1-1987). These standards formalized the mechanical, electrical, and basic protocol parameters of GPIB, but said nothing about
4225-518: Was the forerunner to Standard Commands for Programmable Instrumentation (SCPI), introduced as an industry standard in 1990. SCPI added standard generic commands, and a series of instrument classes with corresponding class-specific commands. SCPI mandated the IEEE 488.2 syntax, but allowed other (non-IEEE 488.1) physical transports. The IEC developed their own standards in parallel with the IEEE, with IEC 60625-1 and IEC 60625-2 (IEC 625), later replaced by IEC 60488-2 . National Instruments introduced
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