Specifications

Chapter 4 - Transient Protection of RS-422 and RS-485 Systems RS-422 And RS-485 Applications Ebook
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Transient Protection of RS-422 and RS-485
Systems
The first step towards protecting an RS-422 or RS-485 system from
transients is understanding the nature of the energy we are guarding
against. Transient energy may come from several sources, most
typically environmental conditions or induced by switching heavy
inductive loads.
4 In This Chapter
What does a surge look like? ....................................................................... 49
When Ground is not really Ground ............................................................... 53
Transient Protection using Isolation ............................................................. 55
Transient Protection using Shunting ............................................................. 58
Combining Isolation and Shunting ................................................................ 60
Special Consideration for Fault Conditions..................................................... 62
Choosing the right protection for your system ............................................... 63
What does a surge look like?
While transients may not always conform to industry specifications,
both the Institute of Electrical and Electronics Engineers (IEEE) and the
International Electrotechnical Commission (IEC) have developed
transient models for use in evaluating electrical and electronic
equipment for immunity to surges. These models can offer some
insight into the types of energy that must be controlled to prevent
system damage.
CHAPTER 4