Echelon Series 6000 Chip databook - Manual (Page 98)

There are two levels of network testing that are relevant to Series 6000 devices:
• Level 3, which represents a typical industrial environment, injects ±1 kV bursts
continuously for 60 seconds
• Level 4 which represents a severe industrial environment, injects ±2 kV bursts
continuously for 60 seconds
In addition, burst testing is performed on the power supply input cable. For Series 6000
devices, the following levels of power supply input testing are relevant:
• Level 3, which represents a typical industrial environment, injects ±2 kV bursts
continuously for 60 seconds
• Level 4 which represents a severe industrial environment, injects ±4 kV bursts
continuously for 60 seconds
Lightning Protection
Protection against lightning is required when designing control networks that run outside of
buildings.
Building Entrance Protection
Echelon recommends using shielded twisted-pair wire for all networks, or portions of
networks, that are run outside of buildings or grounded structures. The shield, as well as
the two network lines, should be connected to Earth ground through Data Line
Lightning/Surge arresters at each building entry point. This connection conducts excessive
energy surges or lightning strike energy directly to Earth and prevents their entry inside the
building through the network shield or data line conductors. Therefore, three arresters
should be used at each building entrance for shielded twisted-pair wiring.
Network Line Protection
The arresters used on the network data lines must be of the Gas Discharge type. The
intrinsically low capacitance to ground of these devices, typically less than 5 pF, minimizes
the corruption of any data signals. Due to their low capacitance construction, the use of Gas
Discharge devices does not alter the maximum number of devices allowed per network
segment.
Important: MOV and TVS protection devices must not be used on the network data lines
because of their much higher capacitance (>200 pF) and potentially poor differential
capacitance matching. These devices can corrupt, and possibly prevent, network
communication between devices.
Shield Protection
Gas Discharge, MOV, or TVS devices can be used for the shield-to-ground protection.
MOV and TVS devices should not be used to protect the network data lines.
Suggested Gas Discharge Arresters
Three-electrode device configurations are suggested for the data network lines, because they
require the use of only one physical device to protect both lines. The network lines should be
connected to the two outside ends of the arrester, while the middle terminal must be
86 Design and Test for Electromagnetic Compatibility