The bus extender complies with the specifications of the ANSI/IEEE Standard 488.1-1987 and
the ANSI/IEEE Standard 488.2-1992, including the Find Listeners protocol. With the GPIB
extenders, you can overcome the following two configuration restrictions imposed by IEEE
488:
•
A cable length limit of 20 m total per contiguous bus or 2 m per each device on the bus,
whichever is smaller.
•
An electrical loading limit of 15 devices per contiguous bus.
Each GPIB-140B system extends the GPIB to a maximum distance of 1 km, and extends the
loading limit to 28 devices (including the GPIB extenders), without sacrificing speed or
performance. You can connect these point-to-point extension systems in series for longer
distances or in star patterns for additional loading.
Using the HS488 protocol, the maximum data transfer rate over the extension is greater than
2.8 MBytes/s. The GPIB extenders use a buffered transfer technique with a serial extension
bus, which maximizes performance and minimizes the cabling cost. Furthermore, the extender
does not affect the transfer rate between devices on the same side of the extension. The GPIB
extender can also check for errors to make sure that the data transmitted successfully over the
fiber-optic link.
Because the GPIB-140B is a functionally transparent extender, the GPIB communications and
control programs that work with an unextended system also work with an extended system.
However, the Parallel Poll Response Modes section describes one exception to this
transparency in conducting parallel polls.
GPIB-140B Dimensions
The following dimensional drawings apply to the GPIB-140B. To find detailed dimensional
drawings and 3D models visit
and search for the device number.
GPIB-140B User Manual
|
© National Instruments Corporation
|
5
