Re: Re: Serial protocol questions

["Frank Mc Alinden" <fmcalind@xxxxxxxxxxxxxx>]

Hi Ben
I was thinking if Neil already has a reasonably simple and
robust  rs485 protocol for his kit , why not look at that and take it from
there ...???

Frank

----- Original Message -----
From: <ben@xxxxxxx>
To: <ukha_xpl@xxxxxxx>
Sent: Sunday, January 23, 2005 5:52 PM
Subject: [ukha_xpl] Re: Serial protocol questions


>
>
>
> You make several compelling points. I do agree it might be best to
> have a polling environment.
>
> I do also think that all HA items should share a similar protocol
> schema. That was the precipitous of my question.
>
> Its sound like the RS485 network should have one standard protocol,
> possibly similar to that of xpl, and then interface via a host PC to
> xpl.
>
> So then, what protocol would work best? Is there a dominant one to
> consider in the HA market?
>
>
> --- In ukha_xpl@xxxxxxx, "Neil Wrightson" <neilw@n...>
wrote:
> > Hi All,
> >
> > I have done a lot of comms work in the past, both RS232 and
RS485.
> > RS485 really has to be a polled environment I.e. a master with
> polled
> > slaves. I'm only just starting to look at Xpl at this stage and
it
> appears
> > that the heartbeat is a rather critical aspect to this protocol.
> > I believe that the RS485 master should be aware of all of it's
> slaves and
> > that the master sends a heartbeat to it's master xXPLHAL??) for
> its self and
> > each of its slaves.
> > Perhaps xPLHAL should advise the master 485 device what slaves it
> should be
> > talking to and what there functionality is.
> >
> > To me part of the question is, should the RS485 network try to
> emulate xPL
> > or as suggested just use a proprietary protocol. I already have
> proprietary
> > protocols in place so this would be easier.
> > But,
> > In my house I do not want to have multiple RS485 networks with
> separate
> > proprietary protocols. I will probably end up making most of my
own
> > hardware, but who knows I may wish to buy somebody else's 485
> hardware item
> > I.e. RFID and connect it onto my network. This wont work if we
all
> have
> > separate 485 protocols.
> >
> > I think one of the early on questions is, What is the master? Is
> it part of
> > xPLHAL I.e. a PC is the master or should there be a separate
> standalone
> > master that talks to HAL via another serial connection. If XPLHAL
> is the
> > master we need somebody that can handle the 485 comms on the PC
> I.e. Rx,Tx
> > and a handshake line.
> >
> > By the way, I have already interfaced to RFID devices. Most
> commercially
> > available RFID devices talk to other equipment via a 26bit
weigand
> > interface.
> >
> > Regards,
> >
> > Neil Wrightson.
> > -----Original Message-----
> > From: Frank Mc Alinden [mailto:fmcalind@b...]
> > Sent: Sunday, 23 January 2005 8:08 AM
> > To: ukha_xpl@xxxxxxx
> > Subject: Re: [ukha_xpl] Serial protocol questions
> >
> >
> >
> > Hi Ben
> >
> >         No one that im aware of has done any xPL stuff using
rs485
> and i
> > have been pondering over the same questions that you are
currently
> asking,
> > as i have some rfid readers and i intend to have a little xPL
rs485
> > network......
> >
> > > 1) Should I be implementing xpl on this device via serial?
> >
> > Can be done ok , but each device must generate hbeats and on a
> rs485 network
> > ,multiple devices could send hbeats at the same time ..???
> >
> > > 2) What schema(s) should I be using?
> >
> > I would assume the control.basic..Sensor.basic could be used here
> >
> > > 3) Would it be better to create a proprietary protocol and
have
> > > someone write a plug-in interface to xpl?
> >
> > Yes this is another option and i have done this with my Probe
> system....
> > You still have the issue of devices sending data at the same time
> therefore
> > getting corrupted messages unless the app polls each device on
the
> network
> > ...???
> >
> > > 4) What resources are available to use as a reference beside
the
> xpl
> > > official website.
> >
> > No rs485 resources that im aware of ....
> >
> > Frank
> >
> >
> >
> > ----- Original Message -----
> > From: <ben@b...>
> > To: <ukha_xpl@xxxxxxx>
> > Sent: Sunday, January 23, 2005 6:24 AM
> > Subject: [ukha_xpl] Serial protocol questions
> >
> >
> > >
> > >
> > > I am in the midst of a project and was thinking about making
the
> > > device xpl compatible.
> > > The device is a magnetic card reader (credit card) with and
> onboard
> > > relay to open an electrical door lock. The idea is you would
> swipe a
> > > credit card this device sends the account number to a host
> computer
> > > (via RS-485). The host determines if the account is allowed
> access
> > > and opens or denies access appropriately.
> > > This device is run by a pic microprocessor.
> > >
> > > Questions:
> > >
> > > 1) Should I be implementing xpl on this device via serial?
> > > 2) What schema(s) should I be using?
> > > 3) Would it be better to create a proprietary protocol and
have
> > > someone write a plug-in interface to xpl?
> > > 4) What resources are available to use as a reference beside
the
> xpl
> > > official website.
> > >
> > > Thanks!
> > >
> > >
> > >
> > >
> > >
> > >
> > > 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
> > > Yahoo! Groups Links
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> >
> >
> >
> > 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
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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
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