Serial control - Would this be possible?

Hi all

Reading all the threads and looking at other items available (such as the globalcache), I started to wonder if it would be possible to have a serial device on the c-bus network.

Basically, press a button on a key input and a serial command is sent to whatever is connected, (say your amp, or video projector or any other serial device)

Could this be done with the current serial device? From what I know of it I don't think so. I think what I am talking about is very similar to a infrared output unit but for serial.

This would allow the integration of c-bus to soar to new heights.

Mick

 

I hear where you are coming from. The idea of allowing other devices to send and recieve to/from the C-Bus modules would open up a big box of possibilities, but may also cause a bigger box of problems. I live mainly in the world of PLC's. Many communication protocols have come and gone, the ones that have stayed around and seem to be most popular also appear to be the most reliable and best supported. Some are expensive, some not so expensive.

The question is, what are we to recieve, and what are we to send. The C-Bus dimmers are good, there is no doubt about that. They are also well priced as far as I can tell. The relays, well, in some cases a PLC would be more cost effective, however, the modular aspect of the C-Bus units may out-way that and turn the tables on a PLC quite a bit. Also, depends on the situation. Domestic or light commercial, a PLC may be out of the question in some ways (ie many 10amp output modules or slave to contactors or relays etc.) and there are key input units, touch screens etc. that match the C-Bus system.

I have toyed with the idea of using PLC's to drive the dimmer modules. It is possible via a PC interface, however, emails to Clipsal regarding protocol have to some extent been un-answered or inspecific. Reasons unknown (but I guess there are reservations). With respects to Clipsals product, which does an admirable job, an AB Micrologix 1500 (as a simple example) has a squizzillion times more processing and thinking power than needed for most domestic and commercial installaions and could be used to 'donkey work' the scenes, scenarios, logical processing of "what if's" and "only when's" etc. Also data logging (serial dump to home PC) and as an interface to SCADA packages, security alarms, fire alarms etc. Analogue interface however, is costly (this is where the Home Minder was good).

Perhaps I (we, if any others are interested in this thread) might ask Clipsal to consider producing a din interface unit that can strip or re-format the bus protocol so it can talk to the outside world in serial, DH485 and Ethernet/EthernetIP. Have the device 'configurable' to filter what we receive and what we send data to (perhaps a separate software package, maybe like a devicenet setup).

Any others with ideas care to comment?

 

Certainly this is technically possible, although Clipsal does not have a C-Bus unit on the market that can do this at the present time.

 

Certainly this sort of thing increasingly makes programming C-Bus more complex. However, this is fact that is becoming unavoidable.

I came from that world as well, mainly from a SCADA background. I can see many parallels with the growth and change of industrial automation 10 years ago and the changes occurring right now in the home/building automation industry.

The distributed nature of C-Bus is a very important part of the product. Central control systems can be cheaper and easier in the short term, but certainly over time they prove to be more expensive and limiting than a distributed system. I have seen this to be true in Industrial Automation (referring to DCS vs. many PLC's). The ability to mix and match C-Bus units and the level of backwards compatibility ensure that a customer can purchase C-Bus products with confidence that the system can grow and expand incrementally without hitting limits requiring significant upgrading of existing hardware. This is a point that will be come more obvious and important in the future when a much wider range of sophisticated units are available on the market.

Please look at the C-Bus Enabled program http://www.cbus-enabled.com on this site you will find the options available to access the protocols. Indeed the protocol required for operating dimmer modules (Lighting Application) is readily available by submitting a web form. Specifically information on the "Open Protocol" for controlling lighting is available here http://www.cbus-enabled.com/cbus-open-b-light.htm

Specifically what protocols would you want supported? (e.g. Modbus Serial).

Would a PC based solution be OK?

 

Watch this space...

Hi guys,

I think you need to watch this space, I reckon you will see just the product released very, very shortly...mmm


PSC.

 

PSC - I await!!!!

Richo - I encourage others to comment here because I have by no means "played all the fields" in this area. I have used other PLC brands (and the PLC interface is the direction I am personally coming from) but have maintained use of Allen Bradley. In the lower cost range, the Micrologix series I would suggest as being quite a fair pick for the domestic/commercial even light industrial markets.

If one was to use the ML1500 (LPR I think?) which has a secondry serial port, (9600 upward) then serial comms would be a must. Messaging instructions to and from a proposed interface is a breeze. I am sure there are many other devices (my own TV for example) that accept ASCII commands by serial information. Direct serial comms does have a length limitation and is a one device to one device situation. In my situation, the PLC to the proposed interface.

There are a number of low cost converter devices - Ethernet to Serial converters; to USB; to parallel etc, and most all laptops and PC's have ethernet these days I would pick Ethernet as the best comms method and (even though the C-Bus network operates at no where near this speed) we should 'future look' and have 1gig/100/10 BaseT comms ability. This would allow a good deal of flexibility I feel. Most PLC's now have modules that talk or message via EthernetIP

Flexibility thus in that the comms from other devices is Ethernet to the PLC, which makes the decisions, and passes instructions/reads data via serial from C-Bus. ... OR ... Ethernet devices with thinking/decision ability talk to C-Bus via ethernet and pass instructions direct (or through convertors) to other devices (TV, Sound system blah blah blah). Hope that makes sense!

Devicenet, Modibus etc, all good but I feel we need to look at consumer orientated products (PC's, Palms, Mobiles, Wireless etc) as probably being the most used "other devices" that would talk to C-Bus.

From my point of view, I do not need to see all the traffic on the C-Bus network, only the devices I wish to exert some control over or obtain information from. I have not as yet followed your suggested links, but will do soon. Hence the suggestion for some 'management software' for the proposed device.

 

A couple of the more "knowledgeable" NSW SI's have developed such a product & it's not up to me to comment about it. All I can tell you is that I believe it will be released very shortly...


PSC.

 

My favorite was Allen Bradley, however I worked on a SCADA product (at a previous employer) and were invloved in (or wrote entirely) drivers for DF1, SNPX and MODBUS ASCII/RTU amongst other very proprietory protcols.

I think Lantronic's makes a smallish processor with ethernet, RS485 and RS232 ports. Coupled with a CNI/PCI yoiu culd use one of these to write a convertor betrween C-Bus and other protocols. Ofcourse you would have ot actually implement the protoclols your self in C code. But it doable, not viable for home jobs but stadiums etc.. would find this viable I think. I recall being invloved in aproject using a lantronic box for this type of thing (no C-Bus) but that was several years ago and the details escape me.

Ok, next step. What sort of access would you want form these devices? Is it that you would want to be able to write applications on these devices that can talk to C-Bus (via whatever mechanism) or would you rather just be able to access a GUI of some sort for control. E.g. accessing HomeGate type screens via a web browser (which can be done now, but ofcourse could always be made easier to use/configure).

Sounds reasonable.

 

NOTED: I will investigate Lantronic further, thanks.

To keep it as simple as I can, yet still get the idea across. I might be hung or impailed for saying this, but the modular and simplicity of the C-Bus system is in it's favour, the dimmers are smooth and reliable, the key inputs are classy and user friendly. The relays are compact, modular and can switch power (10amp+/$ is not bad). My concern is the underlying control of the system (program commands and options) and is "only in my opinion" lagging behind.

Assuming total digital control, a simple PLC would splatter C-Bus control into insignificance. I am sure C-Bus will get better (command wise) over time but in the interrum, there is need for processing some power that steps a bit above the existing commands, especially with new consumer products being released daily that can respond to the outside world in some way.

My thoughts were to utilise a simple PLC (which is no harder to learn to program than Home-minder or C-Bus) as the command centre - the "thought, scene, scenario, output to other devices" processor. This is to complement, enhance, add significant power to the current C-Bus structure. Home-minder is good in it's way, but lacks any real digital power and is horribly long winded, complex and unstructured in its programming (as compared to ladder logic).

The comm needs only read the status (ie. on, off, dim level) of C-Bus modules, and in saying that, only the modules you wish the PLC to exert control over. The comms needs to apply logic to the tags (on, off, dim to%) and again, only over items you wish to control. That's about it.

In this way (quite apart from the endless scene/scenario possibilities) a key input unit (as example) could IR (via C-Bus or via ethernet/ethernet and converter) to a stereo to UP Volume, change CD or whatever - but (perhaps) under a C-Bus parental master control in the bedroom that says "yes you can - or - no you can't its after 11pm you noisy little buggar!"

A good PLC can (through good use of the data file structure) create, implement, dynamically construct, manupliate and logically analyse a class type structure of tags, decide what needs to be done and execute accordingly. The power of such a device is considerably more than that of (for example) Home-minder, BUT it does lack the cost effective analogue facilities that (for example) Home-Minder has to offer.

 

I can't really disagree with anything you said. However, things in this area will be changing in the not too distant future... and I *can't* say any more than that, sorry.

 

Any Crestron processor will enable you to send serial commands to devices from input from C-BUS.
There are many processor to chose from and can be pickup for under $1000.00 that will handle it and much more.
Crestron is @ www.crestron.com

 

Check out...

http://www.integratorsforum.com/showthread.php?t=2840

or

http://groups.yahoo.com/group/amquad_developments/

This is probably what you are looking for