Esd Guidelines; Esd (Electrostatic Discharge) - Siemens LDS 6 Operating Instructions Manual

ESD guidelines

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ESD (ElectroStatic Discharge)

ESD is the rapid, spontaneous transfer of electrostatic charge induced by a high electrostatic
field. Electrostatic damage to electronic devices can occur at any point from manufacture to
field service. Damage results from handling the devices in uncontrolled surroundings or
when poor ESD control practices are used. Generally damage is classified as either a
catastrophic failure or a latent defect.
The symbol to the left indicates an ESD protected area, where all workspaces are ESD
protected and all personnel must wear wrist straps. This symbol will be used in this chapter
to indicate that a service task requires ESD protection.
A catastrophic failure means that exposure to an ESD event has caused an electronic device
to stop functioning. Such failures usually can be detected when the device is tested before
shipment.
A latent defect, on the other hand, is more difficult to identify. It means that the device has
only been partially degraded from exposure to an ESD event. Latent defects are extremely
difficult to prove or detect using current technology, especially after the device is assembled
into a finished product.
Note
Usually, the charge flows through a spark between two objects at different electrostatic
potentials as they approach one another.
It is of utmost importance that ESD protective procedures are used during service in the
field. The components used in SITRANS SL have all been protected from ESD through the
whole production chain.
Ground Everything
Effective ESD grounds are of critical importance in any operation, and ESD grounding
should be clearly defined and regularly evaluated. According to the ESD Association
Standard ANSI EOS/ESD all conductors in the environment, including personnel, must be
bonded or electrically connected and attached to a known ground, bringing all ESD
protective materials and personnel to the same electrical potential. This potential can be
above a "zero" voltage ground reference as long as all items in the system are at the same
potential. It is important to note that non-conductors in an Electrostatic Protected Area (EPA)
cannot lose their electrostatic charge by attachment to ground.
Sensor CD 6C Operating Instructions
Operating Instructions, 12/2007, A5E00912721-02
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