Hey Kai it took me so much time scrolling and digesting your information .

I've learnt two new things " DIRT" and "FARADAY CAGE" .

>Signal ground must see a connection to Faraday cage at each node (modul), at least for
>high frequencies. Otherwise, Faraday cage acts no longer as shield but as an antenna
>injecting noise into circuit. Only if Faraday cage is forced to have same potential as 0V
>of circuit at each modul, no interference can couple into circuit of each modul via stray
>capacitance. Working with safety class I devices containing mains transformer complying
>with safety class I standard, not only metallic enclosure must be directly connected to PE,
>but also signal ground (0V of circuit)!

///// My communication speed is 38 Kilo bits per sec which is 38 Kilo Hz amI correct
how do we convert to KHz. This low frequency surely will couple to the Faraday cage . This
means the system should see some connection to the 0V Right .

OK ,OK ,OK ! , I have got messed up with all this Safety class I and II , some CE directives I'm
hoping . Pl show me a specific picture related to my application ,I have no transformers or
(safety ground, earth, yellow green earth cable) here ,

I repeat :
:::::::::::::::::::::::::::::::::::::::::::::::
I have power from Bus Transit Battery generating 24V DC floating at the out put of its DC-DC
converter .The metal Frame is Floating not tied to -ve of battery ,do you suggest me to * shunt
whatever comes on my line to battery -ve directly because thats the only lowest impedance source
I could locate Right .I plan *NOT* to use Galvanic isolation I think about the following measures:

A) Raising the metal chasis from the Bus frame using TEFLON(R) screws as they dont want us to connect
the -ve of the battery to the Frame atall . Now that I have isolated the metal boxes from its
frame ,I connect the battery -ve to all the metal housing making a star connection with the
-ve of the battery Right Running seven different wires Right.

B) Keeping in mind your suggestion to cut the Faraday cage between the two *NODES* I have to
adopt the measure (A) . If I connect -ve of battery at the master chasis and then connect
the Faraday cage at both ends all the way, this won't either create a loop .

Which above the two is more Robust .

>Connection can also be made by the help of 10...100nF capacitor paralleled by some resistance
of about 1Mohm.
Hey any harm if I connect ( 0v ,Electrical GND ) of my card
to the metal chasis using the R&C combination suggested by you allowing a low impedance path .


:::::::::::::::::::::::::::::::::::::::::::::::

Now the world gets totally different with Malund actually tying his FARADAY
CAGE to 0v of his circuit every where. But he forces me use PE with no exceptions
even when its not available to me right from the very begning of my post . I wanna
know as you work with Buses with wheels is it wise anyway to keep its frame
Floating and where would you tie the shield if your slave and master nodes are to be
raised from the metal housing using some plastic like stuff and you were at my Fuzzy Place .



Kindly/