Re: Re: Serial protocol questions

["DynamoBen" <ben@xxxxxxxxxxx>]

RS485 hubs are super easy to build. In fact you could mock one up on a
breadboard in under 30mins. (They are generally called opto splitters)

Parts Needed:
Several 75176 chips (less than 32)
Several 6N137 chips (this is for opto isloation)

Data path is RS485-->75176 Input-->6N137

Then this would be repeated for the outputs. Don't for get to tie TX to RX.

This make sense?


----- Original Message -----
From: "Frank Mc Alinden" <fmcalind@xxxxxxx>
To: <ukha_xpl@xxxxxxx>
Sent: Monday, January 24, 2005 2:46 PM
Subject: Re: [ukha_xpl] Re: Serial protocol questions


>
> Hi Guys
>        Have to agree with  Lehane that its better to have lots of
small
> devices than to make one that does all ...........
> Would that mean then a rs485 hub would be required so that it could be
> star
> wired ??? anybody did a rs485 hub before ????
>
> Allowing the network to run at different baud rates is a good idea
> ,anything
> i have done is 9600 , although i dont think 19200 would be out of the
> question for most pics...??
>
> The important thing to get this project going i think is to get 
started
> on
> the master device....
>
> Neil  do you have any current hardware to develope a Master on ????
>
>> 2) Presumably the host software will do the device/instance
id->node
>> number conversion and the device/instance config? - Don't know
what this
> is
>> yet ???
>
> Each node has a name / id and its configurable , so when you put a new
> device on the network it will sent out regular requests "please
configure
> me" known as config heartbeats....The master should pick up this
message
> and
> pass it on to the xPL network....In xPL Manager under xPL
> devices,subfolder
> awaiting configuration the device should be listed clicking on it then
> allows you to configure....The config info would get send to the
Master
> which passes it on to the new unit which would reconfigure its self
and
> immediately send out a regular heartbeat.....
> Hope that makes sense ??
>
> Frank
>
>
> ----- Original Message -----
> From: "Neil Wrightson" <neilw@xxxxxxx>
> To: <ukha_xpl@xxxxxxx>
> Sent: Tuesday, January 25, 2005 7:21 AM
> Subject: RE: [ukha_xpl] Re: Serial protocol questions
>
>
>>
>> Hi Lehane,
>>
>> 1) I made reference to the compiler I use purely because it is a
good
>> compiler. Each different type of slave could be a completely
different
> micro
>> and language - assembler, C, Basic Pascal etc etc. The main thing
is that
>> handles its own task and interfaces to the required 485 network
protocol.
>>
>> 2) Presumably the host software will do the device/instance
id->node
>> number conversion and the device/instance config? - Don't know
what this
> is
>> yet ???
>>
>> 3) "Mmm!
>> I'd caution against making the devices too complex. Better have 10
>> types (smaller/cheaper) than 1 do-everything and they are likely
to
>> see the light of day faster. You can always put two/three/four in
one
>> box." - Exactly
>>
>>
>> 4) "So I'd go for:
>> 1 n-way DC input (maybe analogue) variations can include on/off,
>> momentary, dimmer action, etc.
>> 2 n-way DC output (maybe PWM on some for LED's) variations - opto,
>> SSR, etc
>> 3 LCD display driver
>> 4 RFID (...and RFID to me is EPC/ISO 18000)
>> 5 Universal IR (UIRT on 485)
>> 6 Dallas touch and/or one wire sensors
>> 7 MSR (Track 1/2/3)
>> 8 Bar Code Reader (UPC/EAN/ITF/Code 39)
>> 9 Analog input/output (0-5/10V)
>> 10 .... "
>>
>> A) I was thinking of analogue inputs for switches etc, adds
additional
>> security to remote switches I.e. window reed switches or PIR's
>>
>> B) What is "EPC/ISO 18000"
>>
>> C) What is MSR (Track 1/2/3)
>>
>>
>>
>> 5) "Agree on the power to the unit, although 12-15V maybe
sufficient as
>> the power consumption is going to be pretty low on most.
>> Not sure about the audio..I think that belongs on Ethernet in the
>> digital domain. I guess you're looking at voice/audio feedback but
>> would you want output from every device? Or would you command each
>> amp on? "
>> RS485 Cabling is generally as per the old coax 10base2, one long
line
>> with
>> terminators on either end.
>> With up to 32 devices on this line, that means 64 connections,
each with
>> it's own voltage drop. The higher you can have the supply voltage
the
>> less
>> current in the supply lines the less voltage drop on the cable and
the
> less
>> impact of voltage drops on the network connectors.
>> A lot of filed devices requires 12VDC so you would at least have
to add
> 50%
>> i.e. 18VDC for the interconnecting power supply. I know of lots of
off
>> the
>> shelf 24VDC supplies out there. But, I think that as long as we
design
>> the
>> system so that it can handle from 12..24VDC, we can leave it up to
the
>> individual.
>>
>> 6) As far as the audio goes, my intention was that we use the
speaker out
> of
>> the HA pc. Nothing fancy.
>> I see this as been a separate plug in add on board to the main
slave
>> terminal with a small amp etc.
>>
>>
>> 7) RS485 Comms Speed
>> For each slave the master must Tx a message and then Rx a message.
32
> Slaves
>> times * 2 * Packet size of say ten characters = 640 bytes. At 9600
baud
> this
>> would mean dial around would take 1.5 seconds. In reality this
would be
>> somewhat longer with internal delays etc. Hence the reason that I
> suggested
>> 38400 baud. I know basic chips may have issues with this. Again
perhaps
> user
>> definable 9600/38400.
>> Build the network to your own needs.
>>
>>
>> Neil.
>>
>>
>>
>>
>>
>> written in a completely differant language or
>>
>>
>> Regards,
>>
>> Neil Wrightson.
>> -----Original Message-----
>> From: g8kmh [mailto:lehane@xxxxxxx]
>> Sent: Tuesday, 25 January 2005 12:46 AM
>> To: ukha_xpl@xxxxxxx
>> Subject: [ukha_xpl] Re: Serial protocol questions
>>
>>
>>
>>
>> I've dropped my response in below.
>>
>> Lehane
>>
>> --- In ukha_xpl@xxxxxxx, "Neil Wrightson"
<neilw@n...> wrote:
>> > Hi Guys,
>> >
>> > 1) I'm all for a combined project.
>> >
>> > 2) I don't want to start another mine is better than yours
>> discussion, but,
>> > I use AVR's :) I have a great compiler AVRCo with true
multitasking
>> etc
>>
>> To some extent it is irrelevent to most end-users. Few are going
to
>> change code, some will want prog'ed devices and most a kit (or at
>> least PCB and CPU).
>>
>> The protocol outline is doable across a wide range of devices,
indeed
>> it needs to be interoperable.
>>
>> >
>> > 3) I think that a dedicated 485 network controller will be
>> required. I think
>> > the 485 comms will probably run about 38400 baud.
>> >     A 16MHz AVR will happily look after this.
>> >     The network controller will pass and receive all state
changes
>> to the PC
>> > as well as heart beats for each device.
>> >     Comms to the PC could be 9600.
>> >
>>
>> A separate controller has some advantages of redundancy and
>> interfacing with Win* or *nix.
>>
>> With xPL not on the wire then heartbeats can be different
internally
>> to externally.
>>
>> Presumably the host software will do the device/instance
id->node
>> number conversion and the device/instance config?
>>
>>
>> > 4) I envisage that there be at least two types of room
controllers
>> (Perhaps
>> > we should start by settling on some names for these things)
>> >     a) Bedroom/kitchen/Living area Controller wish list
>> >         Display,
>> >         Personnel Switches for lights, sound muting etc,
>> >         Data entry method, Set room alarm clock time etc
Sleep time
>> for
>> > lighting etc
>> >         IR Transmitter, Turn telly off when I fall asleep in
bed,
>> turn
>> > ceiling fan off etc etc
>> >         Personal ID method
>> >         Sound
>> >         Movement sensor interface
>> >         Switch inputs for door & window reed switches
>> >
>> >     b) Basic room as in garage/toilet/bathroom wish list
>> >         Personnel Switches for lights etc,
>> >         Sound
>> >         Movement sensor interface
>> >         Switch inputs for door & window reed switches
>> >         Note - This is to be a cheaper version, no display
only
>> beeper for
>> > sound alerts, maybe a IR receiver for configuration ??
>> >
>> > Hardware Solutions for above
>> >         Display,
>> > 16*2 LCD with LED backlight OR maybe a small graphic LCD,
could
>> display
>> > small icons for
>> >
>> > you have email, voice messages, phone callers etc.
>> >         Personnel Switches for lights
>> etc,                             2..4
>> > Tactile switches I.e. small PCB mount
>> >         Light Control
>> > either 240V relay or triac, triac allows dimming, great for
those
>> wee stops
>> > in the night
>> >         Data entry method,
>> > Universal TV remote. I can currently decode Sony or RC5
signals
>> >         IR Transmitter
>> > IR led on controller as well as capability to add an external
IR
>> led else
>> > where in the room
>> >
>> > for better coverage if needed, I.e. Living room with external
LED
>> for Stereo
>> > etc.
>> >         Personal ID method
>> > Dallas 1 wire ibutton, A lot cheaper & smaller than RFID!
>> >         Sound
>> > 2 Types, 1) Standard beeper. 2) Optional 1W speaker with
sound
>> relaying from
>> > controller Pc
>> >
>> > Probably a separate optional PCB.
>> >         Movement sensor
>> interface                                    As
>> > suggested either a integrated unit actually on the controller
or a
>> separate
>> > security PIR
>> >         Switch inputs for door & window reed switches
>> Standard style
>> > of inputs on a micro 5..12V tolerant.
>> >
>> >         Power Supply and Signal
>> >             I suggest that we use CAT5
>> >             Power - 2 Pairs 1 pair for 0V and one pair for
+24V.
>> >             Comms Signal  - 1 Pair
>> >             Audio from PC - 1 Pair
>> >             If we try to use the standard pin outs for power
over
>> Ethernet
>> > and data signals, nothing will be damaged if
>> >             a wrong device is plugged in somewhere.
>> >             Although, I did see these devices as being panel
>> mounted on the
>> > walls.
>> >
>> Mmm!
>> I'd caution against making the devices too complex. Better have 10
>> types (smaller/cheaper) than 1 do-everything and they are likely
to
>> see the light of day faster. You can always put two/three/four in
one
>> box.
>> So I'd go for:
>> 1 n-way DC input (maybe analog) variations can include on/off,
>> momentary, dimmer action, etc.
>> 2 n-way DC output (maybe PWM on some for LED's) variations - opto,
>> SSR, etc
>> 3 LCD display driver
>> 4 RFID (...and RFID to me is EPC/ISO 18000)
>> 5 Universal IR (UIRT on 485)
>> 6 Dallas touch and/or one wire sensors
>> 7 MSR (Track 1/2/3)
>> 8 Bar Code Reader (UPC/EAN/ITF/Code 39)
>> 9 Analog input/output (0-5/10V)
>> 10 ....
>>
>> Agree on the power to the unit, although 12-15V maybe sufficient
as
>> the power consumption is going to be pretty low on most.
>> Not sure about the audio..I think that belongs on Ethernet in the
>> digital domain. I guess you're looking at voice/audio feedback but
>> would you want output from every device? Or would you command each
>> amp on?
>>
>>
>>
>>
>>
>>
>>
>>
>> xPL Links: http://www.xplproject.org.uk <http://www.xplproject.org.uk>
>> http://www.xplhal.com <http://www.xplhal.com>  http://www.xpl.myby.co.uk
>> <http://www.xpl.myby.co.uk>
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