Siemens Simatic 620 - Manual (Page 184)

Guidelines for handling electrostatic
A-2
SIMATIC Box PC 620 Manual
A5E00131465-01
A.1 What does ESD mean?
Definition
All electronic components are equipped with high–integrated modules or
components. Conditioned by their technology, these electronic components are
extremely sensitive to overvoltages and therefore to discharges of static
electricity.
The short term ESD has been adopted for these Electrostatic Sensitive Devices/
assemblies.
Electrostatic sensitive assemblies are identified by the following symbol:
!
Caution
Electrostatic sensitive devices can be destroyed by voltages which are far below
the limit of perception of human beings. These voltages occur when you touch a
component or the electrical connections of a assembly without being
electrostatically discharged. The damage which arises in a assembly as a result of
overvoltage cannot usually be detected immediately, but only becomes apparent
after a lengthy operating period.