With 485, the third wire is optional. It is recommended if the grounds at
the two endpoints are not "close" The signals are voltage referenced not
current referenced
Because 485 can have such long cable runs (over a kilometer) the grounds in
each building might be very different, if so you need
On Friday 01 January 2021 12:24:55 John Dammeyer wrote:
> > -Original Message-
> > From: nk@nksb.online [mailto:nk@nksb.online]
> > Den Fredag, Januari 01, 2021 06:03 CET, skrev Chris Albertson
> > : �I don't know much about RS485 but I
> > did read that the current return path is required
> -Original Message-
> From: nk@nksb.online [mailto:nk@nksb.online]
> Den Fredag, Januari 01, 2021 06:03 CET, skrev Chris Albertson
> :
> �I don't know much about RS485 but I did read that the current return path
> is required. You should be able to send and about 100K up to 4000 feet.
>
Den Fredag, Januari 01, 2021 06:03 CET, skrev Chris Albertson
:
I don't know much about RS485 but I did read that the current return path
is required. You should be able to send and about 100K up to 4000 feet.
RS-485 use differential signals, currents flowing in differention directions so
retu
On Friday 01 January 2021 00:16:58 Chris Albertson wrote:
> Also, wikipedia has some recommendations but resisters at each cable
> end (resister has the same resistance as the cable's characteristic
> impedance.)
>
> When it works at low speed but fails at higher speed this suggests
> some kind of
Also, wikipedia has some recommendations but resisters at each cable end
(resister has the same resistance as the cable's characteristic impedance.)
When it works at low speed but fails at higher speed this suggests some
kind of cable setup issue. Perhaps wrong volts or wrong termination
resister
I don't know much about RS485 but I did read that the current return path
is required.You should be able to send and about 100K up to 4000 feet.
I'd use a section of Eithernet cable because I know it is twisted inside.
I don't know the best way to provide a "return path for all voltages"
On Thursday 31 December 2020 20:10:35 Chris Albertson wrote:
> Now is the time to connect the digital scope and see what is actually
> on the wire. Is the data bad or is the receiver unable to read good
> quality 38400b data?
>
> This is differential data, it should be able to go half a kilometer
Now is the time to connect the digital scope and see what is actually on
the wire. Is the data bad or is the receiver unable to read good quality
38400b data?
This is differential data, it should be able to go half a kilometer or
something like that. Is it actuary using a twisted pair of wires
Greetings all;
I have this driver working, but at the higher 38400 baud rate, its
reporting a bad crc about every other update loop. Dropping the baud
rate to 19200 fixes it but the screen update rate is correspondingly
slower. The cable is still the amazon full length cable of about 6
feet.
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