Usb Connection Rules - ADInstruments PowerLab 2/20 Owner's Manual

Figure 2–2
Connecting a PowerLab to a
computer with USB.
Chapter 2 — Setting Up
Computer or
hub connection
A plug

USB Connection Rules

1. Cable length should be less than 5 metres (16 feet) between devices.
Devices include USB hubs. There are a maximum of five hubs on
any branch, so the maximum distance between the computer and
the PowerLab is 30 metres (98 feet). Do not use extension cables,
use hubs between approved high-speed cables.
2. Never attempt to make your own USB cable, or modify one.
USB is sensitive to cable impedances and cable lengths. Only use
a certified USB cable from a reliable supplier, never a cheap brand
or 'something the workshop whipped up'. Your PowerLab is
supplied with the proper USB cable. If you need additional USB
cables, you should buy high-speed cables (fully shielded, twisted-
pair, and with standard USB connections) for reliable results.
3. Don't disconnect the PowerLab while a program is using it.
Disconnecting a PowerLab while it is sampling is a bad idea and
may cause problems in some circumstances. It is better to be safe
than sorry, and not even disconnect a PowerLab while Chart or
USB icon
USB cable
PowerLab
connection
B plug
15