Re: Serial protocol questions

["g8kmh" <lehane@xxxxxxxxxxxxxxxxxxx>]

--- In ukha_xpl@xxxxxxx, "DynamoBen" <ben@b...> wrote:
> BTW 1/8 fuses on the data line is always a good idea.

Not sure what is being protected.. if I got 240v on the data line
then some interfaces are dead and I need to get the soldering iron
out. If the fuses blow, the same (given the space requirements they
may be PCB mounted). OK, OK, it's easier to swap a 1206 fuse...

My preference is zener clamping, spark gaps and Varistors.

In answer to some other questions  (not Ben's):

EPC and ISO 18000-6 relate to RFID tags which you'll see on all
products as an adjunct and eventual replacement of bar codes on
everything.

A standard ISO based magnetic (MSR) card has three tracks containing
various amounts of data. Track 2 on a credit/debit card has the basic
information, Track 1 usually has the cardholder name and other info.
Track 3 gets used by banks/ATM's.

There are many barcode specifications - the ones on baked beans are
UPC/EAN but you'll find many others on parcels, pharmaceuticals, etc.
Off the shelf readers will read most of them and tell you what type
by a prefix character ahead of the data.

Digital input can easily handle switches with some optional on board
pull up resistors.

Lehane



> ----- Original Message -----
> From: "DynamoBen" <ben@b...>
> To: <ukha_xpl@xxxxxxx>
> Sent: Monday, January 24, 2005 2:53 PM
> Subject: Re: [ukha_xpl] Re: Serial protocol questions
>
>
> >
> > 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@b...>
> > 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@n...>
> >> 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@m...]
> >>> 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>
> >>> To Post a Message: ukha_xpl@xxxxxxx
> >>> To Subscribe:  ukha_xpl-subscribe@xxxxxxx
> >>> To Unsubscribe:  ukha_xpl-unsubscribe@xxxxxxx
> >>>
> >>>
> >>>
> >>>   _____
> >>>
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> >>>
> >>>
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> >>>
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> >>>
> >>>
> >>> [Non-text portions of this message have been removed]
> >>>
> >>>
> >>>
> >>> xPL Links: http://www.xplproject.org.uk http://www.xplhal.com
> >> http://www.xpl.myby.co.uk
> >>> To Post a Message: ukha_xpl@xxxxxxx
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> >>>
> >>>
> >>
> >>
> >>
> >> xPL Links: http://www.xplproject.org.uk http://www.xplhal.com
> >> http://www.xpl.myby.co.uk
> >> To Post a Message: ukha_xpl@xxxxxxx
> >> To Subscribe:  ukha_xpl-subscribe@xxxxxxx
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> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >
> >
> >
> > xPL Links: http://www.xplproject.org.uk http://www.xplhal.com
> > http://www.xpl.myby.co.uk
> > To Post a Message: ukha_xpl@xxxxxxx
> > To Subscribe:  ukha_xpl-subscribe@xxxxxxx
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> >
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> >
> >
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> >
> >





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