Specifications

Chapter 4 - Transient Protection of RS-422 and RS-485 Systems RS-422 And RS-485 Applications Ebook
Page 50 of 137 Manual Documentation Number: <DocNumber>
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Surge Specifications
Both of the following specifications provide useful information regarding
transients:
IEC 1000-4-5: 1995 "Surge Immunity Test"
IEEE C62.41-1991 "IEEE Recommended Practice on Surge Voltages
in Low-Voltage AC Power Circuits"
These documents define the parameters of a 1.2/50µs - 8/20µs
combination wave surge. The voltage versus time waveform for this
surge has a 1.2 µs voltage rise time with a 50 µs decay across an open
circuit.
Figure 35: Combination Wave Voltage Waveform