Minimizing Effects Of Electrical Noise; Static Electricity And Lightning - Siemens SIMATIC PCS 7 OSx Hardware Manual

Minimizing Effects
of Electrical Noise
Static Electricity
and Lightning
SIMATIC PCS 7 OSx 4.0.0 Hardware (PA RISC)
Avoid sources of electrical noise when installing your system. The main
sources of electrical noise are those devices (and their wiring) that produce
and switch high voltages/currents. Typical examples include:
Power lines carrying 480 volts or higher
Generators
Electric motors
Transformers
Electric welders
Induction furnaces and heaters
Power inverters
Radio transmitters
Walkie-talkies that generate a signal greater than 50 mV
Teletypes
Consider the following guidelines when installing your system.
Avoid parallel runs of AC cables and signal cables.
Avoid running unshielded cables together for long distances.
An electrostatic discharge to magnetic media (for example: hard disk,
diskette, or tape) erases data. The following factors contribute to static
electricity problems.
Carpeting without anti-static properties or treatment
Extremely low humidity
Plastic or vinyl upholstery
Specific clothing/shoe/carpeting or upholstery combinations
Areas subject to lightning storms may require installation of a lightning
protector, particularly if the building is serviced by aerial power lines or if
the power utility has installed lightning protectors on the primary source.
Hardware Overview 1-13