Siemens SIMATIC HMI OP3, Equipment Manual

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D-1
Operator Panel OP3
Edition 11/99
ESD Guidelines
This chapter describes the most important precautions which must be taken to
avoid damage toe the electrostatically sensitive devices in the OP3.
D.1 What Does ESD Mean?
Nearly all modern modules incorporate highly integrated MOS devices and
components. For technological reasons, these electronic components are very
sensitive to overvoltages and consequently therefore to electrostatic
discharge:
The abbreviation for these
Electrostatically Sensitive Devices is ”ESD”
The German abbreviation for such devices is:
”EGB” (Elektrostatisch Gefährdete Bauelemente/B augruppen)
The following symbol on plates on cabinets, mounting racks or packaging
draws attention to the use of electrostatically sensitive devices and thus to the
contact sensitivity of the modules concerned:
ESDs may be destroyed by voltages and energies well below the perception
threshold of persons. Voltages of this kind occur as soon as a device or
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 long period of operation.
In this chapter
Electrostatically
sensitive devices
D