Ground Configuration; Figure 2-4. Mounting Holes Illustration - Advantech MIC-3401 User Manual

2.6 Ground Configuration

Along the top and bottom of the MIC-3401/MIC-3401H are 26
mounting holes. The holes are arranged in an alternating pattern of
chassis (frame) grounded pads and logic grounded pads. The square
pad holes are connected to chassis ground, and the round pad holes
are connected to logic ground. To isolate chassis and logic grounds,
install mounting screws in only square pad mounting holes.
M ounting Holes
M ounting Holes

Figure 2-4. Mounting Holes Illustration

Chapter 2 Hardware Configuration 19