Siemens PC 870 manual Appendix B ESD Guidelines, What does ESD mean?

Appendix B: ESD Guidelines

B

What does ESD mean?

Virtually all present-day modules incorporate highly integrated MOS devices or components. 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 Gefährdeten 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 attention to the use of electrostatic sensitive devices and thus to the contact sensi- tivity of the assemblies concerned:

ESDs may be destroyed by voltages and energies well below the human percep- tion 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 overvoltages 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!

SIMATIC Panel PC 670 / 870 Operating Unit, Equipment Manual	B-1
Edition 07/01