IEEE 488

IEEE 488 is an Institute of Electrical and Electronics Engineers (IEEE) standard for a parallel interface developed by Hewlett-Packard that is used for connecting computers to measurement sensors and test equipment.

What is IEEE 488?

An Institute of Electrical and Electronics Engineers (IEEE) standard for a parallel interface developed by Hewlett-Packard that is used for connecting computers to measurement sensors and test equipment for automatic data acquisition in a laboratory or industrial setting.

Examples of such equipment include signal generators, frequency counters, voltmeters, and temperature sensors.

How IEEE 488 Works

IEEE 488, also known as the General-Purpose Interface Bus (GPIB), provides high-speed parallel communication using a 24-pin connector. An IEEE 488 cable generally has eight single wires for data transfer, eight twisted-pairs for interface handshaking and management, and a drain (ground) wire, all enclosed in an insulating protective jacket.

This configuration provides eight bidirectional channels for transmitting 1 byte (8 bits) of information at a time, at a maximum bus speed of 1 Mbps using tristate drivers. You can chain together up to 15 devices for a total length of 20 meters, with no more than three connectors stacked and no more than 2 meters between adjacent devices.

The master device acts as a controller that determines which device can transmit data over the bus at any given time, while the other devices are placed in standby mode. Only one device can transmit signals on the bus at any given time, but multiple devices can receive those signals.

TIP

If your industrial environment is dusty or has high levels of electromagnetic interference (EMI) from motors, generators, or other heavy equipment, you can obtain special shielding covers to protect your IEEE 488 connectors. You can use switchboxes to alternate several industrial sensors on a single IEEE 488 cable.