Electrical Isolation; Ground Current Safety; Common Ways A Ground Loop Can Exist; Safety Summary & Warranty - Saleae Logic User Manual

Safety Summary & Warranty
Before operating your Saleae Logic product for the first time, please carefully review the safety
guidelines below to avoid any injury and damage.

Electrical Isolation

The input channels on Saleae Logic analyzers are not electrically isolated from each other. The Saleae
Logic is also not electrically isolated from the PC.
High Voltage Safety
Absolute Maximum Voltage Range:
Caution: Connecting one of the input channels to voltages outside this range, even for a very short time,
can result in damage to the device.
Safety Tip: If you're working with high voltages near the absolute maximum limit, first ensure that the wire
harnesses are securely attached to your DUT and you've done some basic testing to make sure the clips
won't pop off your connections. Afterwards, you can connect the wire harnesses to the logic analyzer.

Ground Current Safety

Specifically, this is when a high current flows from the ground pin on the logic analyzer to the ground on
the USB port of your computer, or vice versa. This current can easily damage the logic analyzer, your PC,
and your DUT. All Saleae logic analyzers have fuses in their ground return paths, but these are not
always fast enough to protect the unit from damage.
The user should be cautious of this when the logic analyzer is used in the presence of a ground loop.
Specifically, this means that the logic analyzer is not the only ground path between your DUT and the
host PC. Ground loops by themselves are not necessarily bad, but requires extra caution from the user.

Common Ways a Ground Loop Can Exist:

•
Other USB devices (such as programmers) are connected to the DUT, or the DUT itself is plugged
into the USB port on your computer. In addition to the logic analyzer's ground connection, the DUT's
ground is also connected to the PC's ground through another USB port.
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