GPIB Converters Information
GPIB converters translate data from the GPIB bus to another bus type, and vice versa. For instance, an RS232-to-GPIB converter translates serial commands generated by the RS232 interface into GPIB commands. GPIB converters can manage and govern bus communications (controllers) or serve as a bridge between a GPIB device or instrument and a computer bus (interfaces). They differ in terms of protocol compatibility and connection type to host. GPIB converters also carry specifications for ports and supported operating systems. Features include external indicators for device status, buffers for data spooling, CE Marks, and compliance with FCC rules.
There are two basic types of GPIB converters: GPIB interfaces and GPIB controllers. GPIB interfaces use a port or bus to transfer data between the computer to which the GPIB board is connected and another device or instrument. GPIB interfaces are used in systems that do not require controllers. An example is a configuration with a talk-only device (talker) connected to one or more listen-only devices (listeners). GPIB controllers are converters that send commands to all of the devices in a GPIB network to manage the data flow. In other words, these GPIB converters manage the exchange between talkers and listeners. GPIB controllers are also used to modify a device's status as a talker or listener.
GPIB converters are compatible with IEEE 488.1, IEEE 488.2, or HS 488. The IEEE 488.1 standard, defines mechanical, electrical and protocol specifications for the interconnection of programmable instruments. It also specifies that a GPIB network support a maximum of 14 devices on the bus and a maximum data transfer rate of 1-MBps. IEEE 488.2 is an enhancement to the original IEEE 488.1 standard that standardized data formats, status reporting, error handling, and controller commands for GPIB converters. High Speed 488 (HS488) is a newer, faster protocol developed by National Instruments that accelerates data transfer rates up to 8-MBps using standard GPIB cables.
Connection-to-host is the host computer port through which GPIB converters connect to the host computer. For example, a GPIB-to-USB converter has a USB cable that connects to the universal serial bus (USB) port of the host computer, and a GPIB cable to connect to the rest of the GPIB network. In this way, the USB port in the host computer is used to communicate with the GPIB instrument or network. Choices for connection-to-host include IEEE 1394 or FireWire, telephone line or modem, parallel port, small computer systems interface (SCSI), Ethernet, FOUNDATION Fieldbus, ARCNET, PROFIBUS, DeviceNet, SDS, and CANbus. GPIB converters also differ in terms of supported operating systems.