Functional earth (FE)

The mounting holes also serve as connections for the functional earth (FE, SGND, see subchapter "Notes on analog measured values"/ "Notices on analog specifications"/ "Explanation of the term GND/Ground" within chapter "Commissioning" or appendix in the short documentation).

Make sure that the box is grounded to low impedance via the functional earth (FE) connections. You can achieve this, for example, by mounting the box on a grounded machine bed.