Echelon LONWORKS PLT-22, User Manual

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Table 4.2 summarizes the surge immunity of the PLT-22 transceiver in conjunction
with the line-to-earth coupling circuits specified later in this chapter.
Table 4.2 Line-to-Earth Coupling Circuit Surge Immunity Test Results
Ring Wave Test
(0.5µs-100kHz)
Combo Wave Test
(1.2/50µs-8/20µs)
Product
Location IEEE C62.41-1991
system exposure
level Surge level
verified not to
damage PLT-22 IEEE C62.41- 1991
system exposure
level Surge level
verified not to
damage PLT-22
Branch Circuit low -2kV @70A
med-4kV @130A
high-6kV @200A
4kV @130A
Not specified
3kV @250A
2kV @1,000A
Power Entry low -2kV @170A
med-4kV @330A
high-6kV @500A
6kV @500A low -2kV @1,000A
med-4kV @2,000A
high-6kV @3,000A
6kV @3,000A
Outdoor Wiring
Not specified
6kV @500A low -6kV @3,000A
med-10kV @5,000A
high-20kV @10,000A 6kV @3,000A
(limited by test
equipment)
Fuse Selection
Safety considerations may require a fuse in series with the mains connection. For an
end product to continue to function (without user intervention) it is necessary that the
selected fuse not open following a specified line surge. A minimum 6A time-lag (“slow
blow”) rating has been shown to be necessary to avoid unintentional fusing action at
“high system exposure” levels of IEEE C62.41-1991.
If a coupling circuit which incorporates varistor protection is selected, the varistor
manufacturer’s recommendations for maximum fuse current should be followed. The
vendor listed in the coupling circuits which follow suggests a maximum fuse rating of 6A
for use with 7mm (1200A) varistors and a maximum rating of 18A for use with 14mm
(4500A) varistors.
A 6A time-lag fuse is specified in all of the following coupling circuits since it satisfies all
of the above criteria, as well as the critical requirement that it add very little resistance
(<0.1 Ohms) to the transmit signal path. If a current rating greater than 6A is required
by the application then either larger varistor (>7mm) or gas discharge tube protection is
recommended.
Recommended Coupling Circuit Schematics
This section provides schematics and component information for coupling the PLT-22
transceiver to the power mains. Coupling circuits presented here are unchanged from
those recommended for use with the PLT-21 transceiver. The schematics are divided
into four classes based on coupling method and type of safety isolation. For each
schematic, component specifications and suggested suppliers/part numbers are provided.
4-16 Coupling Circuits