Grounding / Esd Protection - Magtek mDynamo Installation And Operation Manual

2 - Electrical Integration
2.3

Grounding / ESD Protection

To guard against ground loops and to protect the device against electrostatic discharge (ESD), it is
important for the solution design to ground the device correctly. MagTek strongly recommends checking
whether the host's USB port provides earth ground, and whether the selected USB cable carries that
ground all the way to the shield of USB port on the device's board. This will help make an informed
decision about proper grounding. There are two paths to provide earth ground to the device; MagTek
recommends all solution designs bring in earth ground to the device using one and only one of the
possible paths:
•
Bring in earth ground from the host through the USB cable's metal connector shell to the USB Device
Port, See Figure 2-1 for details.
•
Bring in earth ground through the Alternate Earth Grounding Standoff. See Figure 2-1 for details.
Figure 2-1 - Using the Alternate Earth Grounding Standoff
After deciding which point will be grounded, make sure none of the remaining ground points are
connected to a different ground.
In addition, solutions that incorporate devices with a metal bezel must ground the bezel to the same earth
ground potential as the point chosen above. This provides an additional path to protect the device from
electrostatic discharge during card insertion and provides additional protection for the device's
electronics. MagTek recommends this earth grounding cable comprise 18AWG stranded wires.
mDynamo with Outdoor Bezel| IP34 Rated EMV Chip Card Module | Installation and Operation Manual
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