Technical data
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SIMATIC Panel PC 670 / 870 Operating Unit, Equipment Manual
Edition 07/02
Appendix B: ESD Guidelines
What does ESD mean?
Virtually all present-day modules incorporate highly integrated MOS devices or compo-
nents. Due to the technologies used, these electronic components are very sensitive to
overvoltages and consequently therefore to electrostatic discharge:
These devices are referred to in German as Elektrostatisch Gefรคhrdeten
Bauelemente/Baugruppen: EGB.
The more frequent international designation is:
ESD (Electrostatic Sensitive Device).
The following symbol on plates on cabinets, mounting racks or packages draws atten-
tion to the use of electrostatic sensitive devices and thus to the contact sensitivity of
the assemblies concerned:
ESDs may be destroyed by voltages and energies well below the human perception
threshold. Voltages of this kind occur as soon as a device or an assembly is touched
by a person who is not electrostatically discharged. Devices exposed to such overvol-
tages cannot immediately be detected as defective in the majority of cases since faulty
behavior may occur only after a longer period of operation.
Precautions against electrostatic discharge
Most plastics are capable of carrying high charges and it is therefore imperative that
they be kept away from sensitive components!
When handling electrostatic sensitive devices, make sure that persons, workplaces
and packages are properly grounded!
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