Re: Re: Wanted - two pair cable for 12VDC and RS485

[Neil Fuller <neil@xxxxxxxxxxxxxxxxx>]

>>in fact, a screen is likely to bedetrimental to performance IMO.

When we use RS485 to shift data around buildings (which often have high
amounts of EMI from VSDs etc), we always use STP. Why would a screen be
detrimental to performance?

No axe to grind etc - I'm just interested coz sometimes we do have
"problem" buildings and any little snippets would be useful.

Cheers

Neil

Patrick Lidstone wrote:

>--- In ukha_d@xxxxxxx, "martinpalmer8"
<martinpalmer8@y...> wrote:
>
>
>>I am looking for cable with two twisted pairs: one which can carry
>>500mA/12VDC power up to 80 metres and and another which is screened
+
>>twisted and suitable for a RS485 network. The cable will be used
for a
>>variety of applications  - CCTV control, a small RS485 network
>>including a security alarm keypad, lighting control system.
>>
>>
>>
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>Are you sure you want it screened? RS485 is noise immune, and
>shouldn't need screening - in fact, a screen is likely to be
>detrimental to performance IMO.
>
>Patrick
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>Yahoo! Groups Links
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