What is a GPIB?

GPIB interfaces are generally used to connect test equipment and controller devices for effective controlling of test instruments. The GPIB interface was developed with a prime motive to control automated test equipment and till now they are used widely all over the world for the purpose it was intended. GPIB is an acronym for General Purpose Interface Bus, which is also known as the IEEE-488 or Hewlett-Packard Interface Bus [HPIB]. The GPIB is usually used for short range digital communications. These GPIB interface protocols are used for remote control of test equipments, data handshake, response capability and much more. Almost 15 devices can be easily connected with GPIB all sharing separate 8bit electrical bus.

The GPIB interface protocol is connected through daisy chain method
of linkage and the connector of a GPIB interface has twenty four pins.

How GPIB evolved?

Hewlett-Packard [HP] was well known for its test instruments and measuring instrument manufacturing. They developed an interface protocol bus for connecting and controlling test instruments to a computer with ease. Before that, RS232 was popularly used for connections between computer and its peripherals, but this was not reliable when used with test equipment.

Hewlett-Packard Interface Bus [HPIB] was introduced by HP in the late 1960s so that it can implement a reliable and easy method to connect all test instruments with a parallel electrical bus connection. Upon noticing this, several other manufacturers came up to produce these interface busses and they manufactured this interface bus under the name of General Purpose Interface Bus [GPIB]. With the stated advantages of the HPIB, the Institute of Electrical and Electronics Engineers came forward to standardize it and named its standard as IEEE-488.1. Then, it was standardized by the International Electronic Commission [IEC] for worldwide use. The IEC standard was named as IEC 60625.1.

What are the advantages of using GPIB interface protocol?

• As much as 15 external devices can be connected to a computer controller at a time using this GPIB interface protocol.
• The data transfer rate goes up to 1MB/sec.
• The length of the cable used can be of 2m between devices or 20 between a device and a controller.
• 8bit parallel mode of data transfer is used.
• It is capable of having 3 wire handshake.
• In addition to this, more control lines can also be made possible in some special cases like the ATN, EOI, IFC, SRQ, etc.

Use of GPIB in test equipments

As mentioned above, the GPIB interface protocol is used to connect the controller and the test equipment. They transfer the data and control signal from the controller to the test equipment and make the test equipment work accordingly for performing the required test. Almost all the test equipment use this GPIB interface protocols for data transfer as they are reliable and contain adequate transfer speed to perform the task.

Article published December 4th, 2009
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