RE: C-BUS vs. EIB

["Neil Ball" <neilball@xxxxxxxxxxxxxxx>]

Sorry if the post is getting a bit long winded, but comments added at the
end.

Hawes,Timothy Edward (GEG) wrote:
>> -----Original Message-----
>> From: Neil Ball  Sent: 11 March 2004 16:11
>>
>> Hi Tim
>>
>> I think you're confusing EIB with the Siemens product range.
>
> Quite possibly :-)
> Also see the disclaimer at the end.
>
>> Unlike C-Bus
>> which is Clipsal's proprietary network protocol, EIB is an
>> open standard
>> that while developed by Siemens is licensed to other
>> companies e.g. you can
>> buy a complete EIB control system from ABB and others - this
>> is manufacturer
>> used by the chap on Grand Designs who was shown earlier in
>> the series - The
>> Return to Cloud 8.
>
> But, IIRC, he has also set himself up as an Integrator and no doubt
> he paid a substantial sum to do that. From what I read on his site,
> his intention is to offer intelligent BMS after he's completed his
> build so could justify the outlay as a business expense, at least
> notionally, if not actually.
>
>> It may well be that the Siemens EIB implementation adds
>> private extensions
>> to the public protocol thereby preventing full
>> interoperability with other
>> systems and preventing 3rd party software tools from being
>> used. This is
>> mostly the case with other open standards within the controls
>> industry e.g. Lonworks.
>>
>> You are correct over the commissioning issues - Siemens only sell
the
>> software tools and training to approved integrators which are
>> still pretty
>> thin on the ground at the moment.
>
> I'm not quite sure I follow you now. You say I could buy a system
> from ABB for e.g. *but* I would then need ABB to come an commission
> it because Siemens won't sell me the software so I can do it myself.
> I can see the subtle difference between what I said & what you
said
> but we end up at the same place don't we ? i.e. *no DIY*
>
>> Then again, in some areas
>> this is no bad
>> thing. How many would be able to develop and write suitable
>> HVAC control
>> strategies for heating & cooling plant and be able to include
>> all of the
>> necessary safety interlocks, multi-stage frost protection etc
>> that these
>> more complex control systems offer.
>
> Well my day job is specifying PLC systems & writing code to
control
> industrial process plant, but I see where you're coming from ;-)
>
> Although equally, how much of this is required in a domestic
> environment ? If you took a regular boiler and, instead of a normal
> wall thermostat, used an EIB-compatible temperature transmitter and
> some EIB dig outputs, you can repeat the functionality of the normal
> domestic system, but then do much more. Night set-back, time-of-day
> on/off, dial in for remote setpoint adjustment or heating advance
> etc. Nothing particularly earth shattering there, and in many
> respects, what guys here are already doing by other means. I don't
> know CBus, but I would guess you could do something very similar with
> that system too.
>
> Maybe you don't get the full benefit of EIB if you don't use an EIB
> boiler but does it matter ? do they even exist in domestic sizes ? -
> What extra functionality do you need that the above example
> configuration can't provide ?
>
>> Most of these systems only offer
>> programmable I/O which requires someone to design, write and
>> test the code,
>> which is why the manufacturers only use approved integrators
>> most of the
>> time.
>
> Much like a PLC. And CBus. And HomeVision. Like anything, you could
> argue that if you're going to buy a system with the intent of
> programming it yourself, you might check whether you actually have
> the skills to do it, or book yourself on a course. The fact that EIB
> can be scaled up for very large commercial projects I don't think is
> relevant. If EIB is to be offered to the domestic market, the pricing
> and functionality (including the ability to make modifications) has
> to reflect that or it won't sell.
>
> I can buy an Allen Bradley PLC from RS. They don't care whether I
> have the skills to program it - that's my lookout :-)
>
>> Mind you in the case of Siemens I cannot comment on how
>> much HVAC
>> knowledge their integrators actually have.
>
> Pass, but does that matter for many (the majority ?) of domestic
> systems ?
>
>> If you do not need to use analogue sensors or control
>> equipment and only
>> need a digital control system (i.e. VFC in/ relay out) then
>> take a look at
>> the Square-D system.
>
> Thanks for the pointer, I'll check it out :-)
>
> No analogue input sensors can be a significant drawback - take my
> boiler example above. You can always approximate analogue via
> multiple digital switches, but that's not a very elegant solution
> (both from a code POV, and an aesthetic one - wall acne), it's a pain
> to configure and uses up valuable I/O.
>
> Temperature is the obvious requirement for analogue, but what about
> measuring light levels too, and flowrates ?
>
>> It is much more basic, but the
>> interactive training
>> course can be found from their web site. They seem to be
>> trying to recruit
>> electrical contractors to do the install/commissioning so I'm
>> sure they will
>> also sell direct to suitably qualified end users as well.
>
> It will be interesting to see how they define "qualified".
But IMHO,
> that's a good approach for us here on UKHA.
>
> Thanks for your comments - I think it's prompted an interesting
> discussion :-)
>
>
> Cheers,
>
> Tim H.
>

Hi Tim

With regard to ABB I was pointing out that products using the EIB protocol
are available from a number of manufacturers and that these may use
additional proprietary instructions/extensions on top of the basic
protocol.
They still retain their EIB badging, but to fully utilise the advanced
features on a given product range requires using a single-vendor system
approach. This can also mean that the software tools from that manufacturer
have to be used to commission these systems. Whether these are more freely
available from other manufacturers simply depends on the commercial view
taken by that manufacturer. I've not used EIB before but base this opinion
on other "open" protocols such as Lon. The end result though is
just like
you said - no DIY :-(

I do take your point on the HVAC strategies, and that the required
complexity really depends on where the system is aimed. The majority of end
users would benefit from simple boiler control and zoning that could be
centrally accessed and managed centrally and/or remotely. But this does
miss
the higher end of the market where comfort cooling/air conditioning is
becoming more common and larger properties can have multiple boiler systems
etc. In fact many of these properties I have seen can have more complex
services than the average commercial building! There is a need here for
much
more sophisticated control and management without having to resort to
commercial/industrial solutions in my opinion. This is where I see Siemens
trying to capture both the volume market and a share of this higher end
with
their offering.

With regard to the integrator route for commissioning, I suppose you have
to
look at any manufacturers issues with support and perception about quality
of product. A poor implementation is often down to the poor design and
commissioning rather than the product itself. The majority (i.e. those end
users with no technical ability) have enough worries about the technology
going wrong, and stories of badly installed equipment reflects directly on
the manufacturer rather than the integrator in their eyes. The approved
integrator route and restricted access to engineering tools helps to
protect
the integrity of the solution but at the same time denies us the ability to
tinker for ourselves. That may change in time as the market grows and
manufacturers recognise that there are technical users that may well have
greater skills than the official integrators!

I fully agree with you regarding the skills & ingenuity of the group
when it
comes to utilising all manner of devices to create very slick control
systems. I just hope some of these abilities rub off on me :-)

Neil B.



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