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14. Reference Information
14-1 About IEEE-1394
14-1-1 Comparison between IEEE-1394 and other digital interfaces
Since there are many different interfaces available, for example, RS422, RS644, and USB, vision system integ rators
are very likely to be confused when choos ing the right interface for their application. For the ideal design of a
vision syste m, it is vital to have the righ t bus/inte rface. To make things even more complex, ther e is no easy
answer such as IEEE-1394 is the best choice.
Furthermore, the new CameraLink standard, promoted by compan ies such as Puln ix, Basler AG, and many
frame grabb er companies, seems to be the stat e of the art interface. So why should IEEE-1394 be an alternative?
These questions are as complex as mostvision applicatio ns and there is no simple guideline .
Each of these interfaces offers many benefits and each of them has its individual drawbacks and restric tions. In
the table below, we try to give a brief comparison of the most popular interface systems.
Topology
Windows Driver
"Guaranteed"
Bandwidth
Cable Length
Wires Needed for
8 Data Bits
Parameter Port
[1] These specs are for a typical 8-bit camera application operating at 20 MHz or at 40 MHz.
[2] 80% of the bus bandwidth is used for image data and 20% is used for parameter data.
[3] 16 wires are used for data bit transfer and two wires each are used for the separate Line
Valid, Frame Valid, and Pixel Clock signals required with RS-644 transmission.
A careful comparison of the specifications shown in the table should be your first sele ction guide for the inter-
face. For example, for an integ rator who needs very high speed, USB 2 and IEEE-1394 are not the first choice. On
the other hand, these buses are the ones to select in cases
where multiple cameras are needed or cost is a critical issue. Also, the user needs to be aware
that the D-Cam specification curre ntly does not specifically support Line Scan cameras.
However, the specification is open and line scan suppor t could be achieved via Format 7. As
for USB 2, it is still in its infancy in machine vision and we are not aware of any kind of machine vision support.
Samsung Electronics
RS 644 [1]
Link
Proprietary
~20 to 40 MByte/s
~10 m @ 40MHz
~20 m @ 200MHz
22[3]
No
CameraLink
Link
Proprietary
(Win 200, Win 98)
~255 MBytes/s
~32 MBytes/s[2]
~10 meters
10
≥
1 KByte/s
~8 MBytes/s [2]
IEEE-1394
Bus
Native
(Win 200, Win 98)
~38 MBytes/s[2]
4.5 meters
4
~9 MBytes/s [2]
USB 2
Bus
Native
5 meters
2
14-1
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