Instruction manual

Guppy PRO Technical ManualV4.1.0
30
FireWire
1394b bandwidths
According to the 1394b specification on isochronous transfer, the largest rec-
ommended data payload size is 8192 bytes per 125 μs cycle at a bandwidth of
800 Mbit/s.
For further details read chapter How does bandwidth affect the frame rate? on
page 175.
Requirements for PC and 1394b
Note

Certain cameras may offer, depending on their settings in com-
bination with the use of FirePackage higher packet sizes.
Consult your local dealer's support team, if you require addi-
tional information on this feature.
Note

How to extend the size of an isochronous packet up to 11.000
byte at S800:
• See register 0xF1000048, ADV_INQ_3, Max IsoSize [1] in
Table 128: Advanced register: Advanced feature inquiry
on page 212
• See chapter Maximum ISO packet size on page 229
Note

For FireWire accessories see
http://www.alliedvision.com/en/contact
Caution

As mentioned earlier, it is very important not to exceed an
inrush energy of 18 mWs in 3 ms. (This means that a device,
when powered via 12 V bus power, must never draw more than
1.5 A, especially in the first 3 ms.)
Higher inrush current may damage the physical interface
chip of the camera and/or the phy chip in your PC.
For a single Stingray camera inrush current may not be a prob-
lem. But daisy chaining multiple cameras or supplying bus
power via (optional) HIROSE power out to circuitry with
unknown inrush currents needs careful design considerations.