Siemens OP5 Equipment Manual page 153

ESD Guidelines
In this chapter
This chapter describes the most important precautions which must be taken to
avoid damage toe the electrostatically sensitive devices in the OP3.
E.1 What Does ESD Mean?
Electrostatically Nearly all SIMATIC assemblies incorporate highly integrated MOS devices
sensitive devices
or components. For technological reasons, these electronic components are
very sensitive to overvoltages and consequently therefore to electrostatic dis-
charge.
These devices are known internationally as:
"ESD" (Electrostatic Sensitive Devices)
The German abbreviation for such devices is:
"EGB" (Elektrostatisch Gefährdete Bauelemente Baugruppen)
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 sensitivity of the assemblies 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 an
assembly is touched by a person who is not electrostatically discharged. De-
vices exposed to such overvoltages cannot immediately be detected as defec-
tive in the majority of cases, since faulty behavior may occur only after a
long period of operation.
Manual OP5, OP15
( ) J31069-D0840-U001-A2-7618
E
E-1