
the 80% AM). Level 3 testing, which represents a “harsh industrial environment,” is
performed with an injected common-mode voltage on the EUT’s network cable of 10Vrms
(50.9Vp-p including the 80% AM).
Note that the CDN test method is the preferred method according to the EN 61000-
4-6 specification. The T2 and S2 CDN models shown in the figures allow LPT-11
network communications to pass through them with negligible signal degradation.
Echelon recommends using these CDNs for EN 61000-4-6 testing of LPT-11
transceiver-based devices, rather than using the alternate “Bulk Current Injection”
(BCI) technique.
A typical set-up for EN 61000-4-6 testing of an LPT-11-based device and unshielded
twisted pair network wire is shown in figure 6.4.
Figure 6.4
Typical EN 61000-4-6 Test Set-up for Unshielded Twisted Pair (UTP)
For the EN 61000-4-6 tests, the EUT is placed on a 10cm high, non-conducting
support on top of the metal ground plane. If the EUT’s chassis is connected to earth
ground in typical installations, then it should be connected directly to the metal
ground plane during the EN 61000-4-6 tests via a short wire. If the EUT is left
floating in normal use, then there should be no connection between the EUT and
earth ground for the EN 61000-4-6 tests. The power is supplied by an LPI-10 source
coupler, placed on the AE side of the CDN. During the network immunity tests, any
I/O lines that come out of the EUT should also pass through a decoupling network.
6-10
Design
Issues