Guidelines for Handling Electrostatically-Sensitive Devices (ESD)
B-4 AutomationSystem S7-400 Hardwareand Installation
A5E00850741-01
B.3 General Protective Measures Against ElectrostaticDischarge Damage

Ensure Sufficient Grounding

Make sure that the personnel, working surfaces, and packaging are sufficiently
grounded when handling electrostatically-sensitive devices. Youthus avoid
electrostatic charging.

Avoid Direct Contact

Youshould touch electrostatically-sensitive devices only if it is unavoidable
(for example, during maintenance work). Hold modules without touching the pins of
components or printed conductors. In this way,the discharged energy cannot affect
the sensitive devices.
If you have to carry out measurements on a module, you must discharge your body
before you start the measurement by touching grounded metallic parts. Use
grounded measuring devices only.