Hi Everyone,

As promised in my first post. This is my second white paper where I compare Z-Wave with CBUS/MODBUS systems in terms of Design Architecture. But the catch is Design Architecture may highly affect investment protection in the long run.

Here is an Excerpt:
As Smart Home Automation technology is taking the market at large in the UAE and around the world, it becomes imperative to understand the different options in terms of technology architecture as this can save a real estate owner from venturing into an investment that will cost them more to maintain than any form of Return on Investment from the solution.

This document is dedicated to compare the design architecture of Z-Wave against MODBUS or CBUS based systems. Features or detailed specs about the protocols will not be discussed as the difference in design architecture between these protocols and their components may be more than enough in order to make a decision on what technology can give the greatest investment protection.

Design architecture in this document will refer to the interconnections at the level of lighting circuits. In very basic form, and in a normal house that does not have any Smart Home capabilities, a ceiling light would be connected in series with a light switch and the electrical distribution board (DB). The 220V line would start at the electrical DB, enter a standard relay, go to a junction box where a standard light switch is connected, then from the junction box to the ceiling light and back to the Electrical DB’s neutral connection.

Z-Wave network architecture is exactly the same as the standard connection described above, and that is why Z-Wave systems can be retro-fit into any existing home. In order to install this system, all what is required is to replace the standard lighting switch in the junction box with a Z-Wave enabled light switch. All other remaining connections to the DB and to the ceiling light remain un-touched.

All the intelligence lies in the wireless switch installed in the junction box. A Smart Home server or controller will then have to send commands wirelessly to that switch to turn “ON”, “OFF”, or “DIM” the lights.

MODBUS or CBUS based systems on the other hand, use a completely different architecture which is non-standard in comparison with the standard home lighting system (described first in this document). In MODBUS or CBUC systems, the connections between the DB and the ceiling lights, and between the DB and the junction box (wall switch) are completely separate. In addition, there are no connections between the Junction Box and the respective ceiling lights. The Intelligence of a MODBUS or CBUS system lies in a “Channel Dimmer” or “Channel Relay” which is installed in the DB and would replace the traditional standard relay installed in existing homes today. This “Channel Dimmer” would have a 220V Line interconnection directly to the ceiling light and a neutral connection back from the ceiling light to the “Channel Dimmer”. The “Channel Dimmer” will control the light directly and will receive its commands either from a rail mounted controller that is connected to its communication port (could be a serial port), or manually from a wall mounted light switch/keypad. This wall mounted light switch would not be connected to any load whatsoever, it would be directly connected with the “Channel Dimmer” by means of a control/signaling cable. The “Channel Dimmers” normally come as 4-channel or 8-channel, this means that they can be connected to 4 or 8 separate lighting circuits at the same time and this din-rail mounted device is also a single point of failure for all these 4 or 8 lighting circuits.
and here is the link to my website for the full article. (Includes design diagrams to illustrate the above)