Siemens Plant Central Clock TC100 - Manual (Page 110)

B-10 © Siemens AG 2010 All Rights Reserved
SICLOCK ® TC100 Operating Instructions
ESD guidelines
B
B.1 Electrostatic sensitive devices
Definition
All electronic modules are equipped with highly integrated ICs or components.
Due to their design, these electronic elements are highly sensitive to overvoltage,
and thus to any electrostatic discharge.
Electrostatic Sensitive Devices are frequently referred to by the abbreviation
ESD. This is also the international abbreviation for such devices.
ESD modules are identified by the following symbol:
Figure B-1 Electrostatic sensitive devices
Caution
Modules susceptible to electrical discharge can be destroyed by voltages that fall
far below the limits of human perception. These voltages even occur if you touch
a component part or electrical connections of a module without being electrosta-
tically discharged. The damaged caused on a module by an overvoltage is not
usually recognized immediately, but only becomes evident after a longer period
of operation.