Contec GPIB-FL2-USB, Справочное руководство

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Connecting to an External Device
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GPIB-FL2-USB Reference Manual
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1. Connecting to an External Device
1. Notes on GPIB cable connection
The GPIB has restrictions on the number of devices connected and the cable length according to the
standard.
1
The maximum number of interfaces (external devices) is 15, which can be connected to one
system.
2
The maximum total length of cables that can be used to interconnect a group of devices in one
bus system is “2 m x (the number of devices)” or 20 m, whichever is shorter. (JIS C1901-1987)
Note, however, the individual cables between devices must be within 4 m long.
Some examples are given below.
- System with a total of two devices
2 m x (Number of devices = 2) < 20 m
The maximum total length of cables for this system is therefore 4 m.
- System with a total of three devices
2 m x (Number of devices = 3) < 20 m
The maximum total length of cables for this system is therefore 6 m. The two cables used in
the system must be [2 m + 4 m] or [2 m + 2 m] in length so that neither is longer than 4 m.
- System with a total of fifteen devices
2 m x (Number of devices = 15) > 20m
The maximum total length of cables for this system is therefore 20 m.
3
The cables in the system must not form a loop.