Pay Attention on GND connection

WisdomAugust

Handling Precautions

The product will share one reference which is typically connected to earth ground through the power cord with your PC after you connect the product to your PC with USB cable. The probe ground lead is at ground potential.
Do not connect the ground lead to an elevated voltage. If you connect the probe as Figer 1, it will break the product and your PC. If measuring the floating potential, we will recommend the measurement as follows.
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1.       If product and your circuit share one ground, make sure that connect the ground lead of the probe to earth ground only. (As Figure 2).
2.       Use isolated power supply for your PC or your circuit.
3.       Use a notebook PC which use battery power supply only.
4.       Use differential motion method using CH1 and CH2. (Figuerr2)