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RS485
Sci.Electronics.Design is a worldwide Usenet news group that is used to discuss various aspects of Electronic Circuit Design.
We found 32 threads matching "rs485"
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RS485 trouble
ScadaEng - 2010-06-11 18:42:00
I have worked allot with RS232, and other serial protocols, but this is my
first RS485 project. It seemed straight forward to me, but now I have a big
problem.
I am using the max490 chip. I'm doing full duplex, 4 wire. Each of my nodes
have the max490 communicating with a 16F877A pic chip. ...
diagnosing non working rs485 bus
bill13 - 2010-03-18 09:10:00
I am trying to figure out why my prsamp and keypads do not communicate. I
have an elan z630 and z100 keeypads. they communicate through an rj45 jack
that has two wires labelled rs485+ and rs485-. The key pads have power and
the led light up red. It is suppossed to light green. I opened the prea...RS485 resistors
Marco Trapanese - 2008-01-11 05:14:00
Hello,
I'm talking about the usual RS485 front-end: MAX485, series resistors
(if any), pull-up/pull-down and termination resistor.
The system I'm working on has two RS485 transceiver at both ends of a
twisted-pair cable. Its length is between 250 m and 500 m.
I'm wondering how to dime...RS485: testing loopback
Ajab - 2007-12-21 03:27:00
I am using a rs232 to wire rs485 converter. I have shorted TX+ with RX
+ and TX- with RX- for 2-wire configuuration. A 120R termination
resistor is connected between TX+ and TX-.
I am using it in half-duplex configuration.
Is it possible to test loopback. Because in half-duplex either tx or
rx ...RS485 Timeout
2008-01-09 15:35:00
Hi,
I am writing an application for a RS485 network. Basically, a client
server program.
So when server sends command out, the client who receive it send some
data back.
My question is that how long the timeout should be for the server? How
long should the server wait before report a time ou...RS485/422 Isolated Network
Babak - 2008-02-22 10:01:00
Hello All,
Could you validate the following assumption(s) on isolated network
implementation
1) An isolated RS485/422 Comport can connect to the none-
isolated network.
2) Having more than one isolated comport will require a separate
isolated power source for each of the isolat...rs485 bus on preamp not working
bill13 - 2010-03-18 09:10:00
i suspect it will take the audience about 5 secs to realize I am a novice
but I have an interesting problem and would like to see if experts can make
a novice into a functional apprentice via the web.
In simple terms: I have a preamp that connects to keypad through a rs485
bus communiction port....help needed for rs485 !!!!
michael nikolaou - 2009-04-05 03:11:00
Hi to newsgroup
I want to implement an RS485 interface to an microcontroller with the
purpose of creating a network of 10 controllers
located about 200 mt from a pc . Although everything is clear regarding the
interface what is obscure is the protection
needed. I've seen schemes using a 100...RS485 grounding part 2
mkr5000 - 2008-09-21 10:03:00
I've read some material (a Jan Axelson article), that further confuses
me on this matter of proper RS485 grounding for the shield that
surrounds our twisted pair of data.
Like I say, I have always just grounded just one end to a good EARTH
ground, either my transmitter or receiver, depending o...Re: Powering isolated RS485 transceivers over cable
keithw86@gmail.com - 2010-07-15 14:44:00
On Jul 15, 10:25=A0am, "markp" wrote:
> > > Hi All,
> > > I have an application that requires about 12 sensor devices over a RS4=
85
> > > cable, evenly spaced over about 20m with a controoler at the end.
>
> > > I'd like to use galvanically isolated RS485 buffers such as IL3185 on...SBC+Display
Dirk Bruere at NeoPax - 2009-02-19 07:58:00
Looking for a very basic SBC with RS485, IR receiver and capable (or
with) a multiline back lit color text display. I don't need much
processing power - it just needs to display text and pick up IR.
Anyone make something like that?
Dirk
...replacing a rs485 transceiver chip
bill13 - 2010-03-22 12:13:00
I am going to replace a transceiver chip on my preamp so it talks to my
keypad which by the way has the same transceiver in it (max1843).
Typically I have no trouble soldering but I am new at surface mount. I am
willing to take shot at it. Whats best heat gun and solder paste or solder
gun and so...SPDIF to AES/EBU
Dirk Bruere at NeoPax - 2010-03-02 16:49:00
Looking for a reliable circuit for the level conversion from SPDIF to
TTL. I then intend to feed it to an RS485 driver and into a transformer
for transmission via CAT5e
--
Dirk
http://www.transcendence.me.uk/ - Transcendence UK
http://www.theconsensus.org/ - A UK political party
http:/...Re: Why do we have cross-over cables.
Jasen Betts - 2009-03-23 21:42:00
On 2009-03-23, Jeroen Belleman wrote:
> > No it doesn't. It entirely misses the point, which is why there is a
> > distinction betwen DCE and DTE.
>
> It would surely be much nicer if equipment at both ends of the link used
> just a single pair to communicate in both directions, full...Re: ethernet over a single pair of wires?
mook Johnson - 2008-02-05 21:14:00
>
> I can't see why it shouldn't work. I've certainly managed to get 100Mb
> half- duplex operation by accident when debugging Ethernet (KS8993/5)
> designs. I expect all switches do autonegotiation now. But if you're
> worried, it's easy to try out- just take an ordinary Windows network...Profibus VP power supply (+5V)
markp - 2010-07-21 10:00:00
Hi All,
I'm designing a Profibus interface. I'm a little confused with the +5V
termination power supply (Voltage Plus, or VP). My understanding is that VP
is supplied by something on a segment that is used to actively terminate all
the receivers, and usually these resistors are in the Profi...Re: How to interface a microcontroller to fibre optic?
Oliver Faust - 2009-03-31 03:57:00
Dear Graham,
Thank you for your response.
> 8051 family devices have a UART that in one mode will run at 1 Mbps with
> as 12MHZ clock crystal.
This is one of my problems, from what I have read a simple UART can't
be used for fiber optic transmission. As far as I know there is no
optical tran...Re: Which multi-PIC mid-range comms protocol?
Grant - 2010-08-12 06:12:00
On Thu, 12 Aug 2010 10:38:24 +0300, Tauno Voipio wrote:
> Jamie wrote:
> > > emulating a PCF8574 I/O expander (and cheaper then one :-) ).
> > MODBUS/RTU on a balanced twisted pair( 485 ) works well, the MODBUS
> > supports 31 devices.. A well known protocol, why reinvent the wheel?
> ...MOS optocouplers...
Arie - 2008-04-28 13:55:00
A rather strange effect puzzled us today...
We use a MOS optocoupler to switch a RS485 terminator. The production test
sometimes failed and indicated the terminator was on while it should be off.
When probing the drive to the optocoupler, it sometimes switched on or off,
depending on when or w...Re: Any gotchas using CAN bus?
Robert Adsett - 2008-04-04 10:51:00
In article , Mook Johnson
says...
> I have a project where CAN bus is being proposed for connecting several
> custom instruments together on a 200Ft long single twisted pair.
>
> I am no serial protocol expert but when CAN was brought up in two seperate
> other venues, it got shot d...Re: Uses for old TVs?
Martin Riddle - 2009-06-23 20:05:00
"Jim Thompson" wrote in
message news:tg6245hquf5k6550qlnrpdtl4g6tl62qfi@4ax.com...
> On Tue, 23 Jun 2009 11:02:38 -0700, "Paul Hovnanian P.E."
> wrote:
>
> > Too_Many_Tools wrote:
> >
> > > With the advent of digital OTA, lots of good analog televisions are
> > > being surpl...Re: Driving 0.5km CAT5
David L. Jones - 2010-01-08 07:17:00
pimpom wrote:
> Prelim: If anyone remembers me from previous posts, please note
> that constraints imposed by my location dictate that I use, as
> far as possible, only long-established standard components in my
> projects.
>
> I want to send two independent unidirectional pulsed signals...Re: Driving capacitive loads with an H bridge
Grant - 2010-07-25 21:33:00
On Sun, 25 Jul 2010 16:00:54 -0700, John Larkin wrote:
> On Mon, 26 Jul 2010 08:49:12 +1000, Grant wrote:
>
>
> > > The four switches here
> > >
> > > ftp://jjlarkin.lmi.net/Triangle_Cap.JPG
> > >
> > > make an h-bridge. The a-a and b-b switch pairs are alternately turned
> > > ...Re: Tunable Bandpass Filter
ChrisQ - 2009-11-18 17:30:00
Joel Koltner wrote:
> "ChrisQ" wrote in message
> news:eCRMm.661$mC4.267@newsfe22.ams2...
> > Haven't done much radio for years.
>
> So what kind of things do you work on these days?
Have been freelance since the mid 1970's. Now getting a bit wrinkly, but
manage to stay in work m...Re: Backplanes and daughter boards. Connecting the same signal lines to a large number of boards/chips
markp - 2010-08-11 20:03:00
"M. Hamed" wrote in message
news:40703d15-7a81-4a50-939e-accabe44b6be@k1g2000prl.googlegroups.com...
> Hello there,
>
> I'm part of a team that has been assigned the task of designing a
> system consisting of a backplane and a number of daughter board. Each
> daughter board will hav...Re: Tunable Bandpass Filter
JosephKK - 2009-11-20 07:39:00
On Wed, 18 Nov 2009 22:30:33 +0000, ChrisQ wrote:
> Joel Koltner wrote:
> > "ChrisQ" wrote in message=20
> > news:eCRMm.661$mC4.267@newsfe22.ams2...
> > > Haven't done much radio for years.
> > =20
> > So what kind of things do you work on these days?
>
> Have been freelance sin...Possible Latchup problem with RS485 transciever
logjam - 2008-10-11 16:06:00
I have a project where the input of an RS-485 receiver can have
voltage on it before the main power supply comes on.
My project has worked well in the past when my cable's bus voltage was
12v and I used some 12v to 5vDC Astrodyne DC-DC converters.
I am now using a cable bus voltage of 48vDC ...Re: my lab
Martin Brown - 2009-10-12 05:11:00
krw wrote:
> On Sat, 10 Oct 2009 13:57:47 +0100, Martin Brown
> wrote:
>
> > krw wrote:
> > > On Fri, 9 Oct 2009 17:42:58 -0700 (PDT), a7yvm109gf5d1@netzero.com
> > > wrote:
> > >
> > > > On Oct 9, 7:09 pm, Joerg wrote:
> > > >
> > > > > GPIB is terrible. The topper happen...Re: Location of phone wall sockets
Ross Herbert - 2009-04-05 23:26:00
On Sat, 04 Apr 2009 17:20:13 +0100, Don wrote:
:On Sat 04-Apr-2009 09:41, David Woolley wrote:
:> Don wrote:
:> >
:> > I am moving the telephone wall socket in my study because I'm
:> > often checking out some extra phone device and need better
:> > access than a single socket at...Re: my lab
krw - 2009-10-12 22:59:00
On Mon, 12 Oct 2009 21:01:29 -0400, Phil Hobbs
wrote:
> krw wrote:
> > On Mon, 12 Oct 2009 10:11:05 +0100, Martin Brown
> > wrote:
> >
> > > krw wrote:
> > > > On Sat, 10 Oct 2009 13:57:47 +0100, Martin Brown
> > > > wrote:
> > > >
> > > > > krw wrote:
> > > > > > On ...Re: Minimum frequency on Cat.5
2008-12-17 17:55:00
I hate interleaving stuff but just have done :)
va...@silvtrc.org wrote:
> john@jjdesigns.fsnet.co.uk wrote:
> > The 1000's of metres of CAT5 I've measured looks perfectly 'normal'
> > from DC to way beyond 100MHz. (as any old bits of wire should). At low
> > frequencies you only need ...Re: ucontrollers (AVR/ATMega) and radio transceiver modules
Tim Watts - 2010-01-25 07:52:00
On Mon, 25 Jan 2010 03:17:50 -0800, John Walliker
wibbled:
> On 25 Jan, 10:22, Tim Watts wrote: I fancy having a
> > play with some radio datalinks (with a view to home automation) - but
> > there seem to be a million modules and a fair number of
> > frequencies and standards. I'm j...