GW Instek GDS-2000A series Quick start guide for Logic analyzer option - Manual (Page 8)

Using the Logic Analyzer Probes
This section will describe how to connect the digital
channels to the device under test. To use the digital
channels the optional logic analyzer module must be
installed.
1. Turn the DUT off to protect it from being short
circuited when the probes are attached.
2. Insert the Logic Analyzer
probe into the Logic
Analyzer input.
3. Connect the ground lead (black) from the logic
analyzer probe to the circuit ground on the DUT.
GND
4. Connect another probe lead to a point of interest
on the circuit. Make note of which probe lead is
connected to which point.
5. Repeat step 4 with any remaining probes.
GND
Signal 1
Signal 2 . . .