Kvaser U100S User’s Guide
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you can use USB hubs or USB extension cables with a built-in hub. By chaining up
to 5 hubs, you can achieve an effective cable length of up to 25 m (
∼
82 ft).
As USB cables become longer they are more sensitive to EMI,
because they make a longer antenna that can pick up more
noise. These issues can be mitigated by using higher quality
cables with better shielding. Thicker cables tend to be better than
thin ones, and braided shielding tends to be more reliable than
only foil. Furthermore, longer cables may introduce signal
degradation and timing issues that, if necessary, can be mitigated
using shorter cable segments combined with hubs that amplify
the signal and handle delays on a per-cable basis.
3.3
Kvaser MagiSync
Time synchronization is needed to achieve accurate and precise time stamping
between several PC-to-bus interfaces connected to one PC. Since each PC-to-bus
interface uses its on-board clock to set the time stamps.
Kvaser MagiSync is an innovative way to synchronize several different Kvaser USB
interfaces. You do not need external cables - you get instant synchronisation when
you connect the MagiSync enabled Kvaser USB device.
Figure 3: An example setup where all devices are synchronized via MagiSync.
For this to work the Kvaser USB interfaces must reside on the same USB root hub.
If they do not they will not be synchronized, see Figure 3 and Figure 4 on Page 9.
Usually, a computer has a USB controller with one root hub in a computer. If you
use that one, you do not need an external USB hub to get your Kvaser Devices
synchronized. The easiest way to verify the setup is to view Synchronized
Kvaser AB, Mölndal, Sweden — www.kvaser.com
