What is Z-Wave?
Zwave is a protocol for communication among devices used for home automation. It uses RF for signaling and control. smarthome.com, Smarthome, check out Simply Automated UPB, Zwave vs. insteon vs. upb vs. x10, was developed by Zensys, Inc. a start-up company based in Denmark. Zwave was released in 2004. Based on the concepts of Zigbee, Zwave strives to build simpler and less expensive devices than Zigbee. In 2009 Sigma Designs of Milpitas, CA purchased Zensys/Zwave.
Dozens of manufacturers make Zwave compatible (to a lessor or greater extent) products, mostly in the lighting control space.
The Basics
Zwave operates at 908.42 MHz in the US (868.42 MHz in Europe) using a mesh networking topology. A Zwave network can contain up to 232 nodes, although reports exist of trouble with networks containing over 30-40 nodes. Zwave operates using a number of profiles (think of them like languages), but the manufacturer claims they interoperate. Use care when selecting products as some products from certain manufacturers are not compatible with other manufacturers’ products.
Zwave utilizes GFSK modulation and Manchester channel encoding.
A central, network controller, device is required to setup and manage a Zwave network. Each product in the home must be “included” to the Zwave network before it can be controlled via Zwave (and before it can assist in repeating/hoping within the mesh network).
Each Z-Wave network is identified by a Network ID and each device is further identified by a Node ID.
The Network ID (aka Home ID) is the common identification of all nodes belonging to one logical Z-Wave network. Network ID has a length of 4 bytes and is assigned to each device by the primary controller when the device is added into the network. Nodes with different Network ID’s cannot communicate with each other.
The Node ID is the address of the device / node existing within network. The Node ID has a length of 1 byte.
Z-Wave uses a source-routed mesh network topology and has one primary controllers. Secondary controllers can exist, but are optional. Devices can communicate to one another by using intermediate nodes to route around and circumvent household obstacles or radio dead spots that might occur though a message called “healing”. Delays will be observed during the healing process. A message from node A to node C can be successfully delivered even if the two nodes are not within range, providing that a third node B can communicate with nodes A and C. If the preferred route is unavailable, the message originator will attempt other routes until a path is found to the “C” node. Therefore, a Z-Wave network can span much farther than the radio range of a single unit; however, with several of these hops a slight delay may be introduced between the control command and the desired result.[5] In order for Z-Wave units to be able to route unsolicited messages, they cannot be in sleep mode. Therefore, battery-operated devices are not designed as repeater units. A Z-Wave network can consist of up to 232 devices with the option of bridging networks if more devices are required.
As a source routed static network, Z-Wave assumes that all devices in the network remain in their original detected position. Mobile devices, such as remote controls, are therefore excluded from routing.
Z-wave released later versions with added network discovery mechanisms so that ‘explorer frames’ could be used to heal broken routes caused by devices that have been moved or removed. A Pruning algorithm is used in explorer frame broadcasts and are therefore supposed to reach the target device, even without further topology knowledge by the transmitter. Explorer frames are used as a last option by the sending device when all other routing attempts have failed.
About UPB Technology
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Highly Reliable — The UPB method of communication is 100 ~ 1000 times more reliable than current X-10 technology and 10 ~100 times more reliable than CEBUS or LONWORKS powerline technologies. UPB is 99.9% reliable versus 70%-80% reliability of X-10.* UPB transmits farther (over a mile), is less susceptible to powerline noise and capacitive attenuation (signal reduction) than other technologies for three reasons:
When put on one phase of a home’s two phase power line, the signals are so strong they go out to the street side transformer and are induced on the opposite phase, returning back to the home. Since UPB transmits at a low frequency, it does not affect other powerline devices or appliance/loads. No New Wires – UPB dimmer switches are installed exactly like regular dimmer switches. They connect to a home’s standard wiring. Since no new or special wiring is required, they work great in retrofit applications too. Affordable — UPB dimmer switches can be as affordable as high end non-communicating dimmers. When comparing costs of home upgrades (theater TV, remodeled bath or kitchen) adding lighting automation and control to a room or whole home provides a surprising improvement in quality of life at a comparably low cost. Simplicity – Adding lighting control can be as simple as plugging in dimming modules or replacing dimming switches Pre-Configured Series. Unlike radio frequency (RF) wireless switches, where reliability is proportional to the number of ‘mess-networked’ switches installed, UPB provides reliability and performance anywhere in the home without the need of repeaters. Peer to Peer – No host computer or central controller is necessary for single, point-to-point control or group (lighting scene) control. UPB is a no-host, peer to peer network. Interruption of power, or single point controller/repeater failure, will not affect a stand-alone UPB network. Two Way Communications – Hardware, software and protocol design allows for two-way communication in all products. Status can be confirmed with polling or automatically transmitted upon local/manual load changes. House Separation – Neighbors with UPB will not control each other’s lights. The UPB addressing scheme allows for 250 systems (houses) on each transformer and 250 devices on each system. It incorporates over 64,000 total addresses compared to 256 for conventional X-10. Interaction – UPB communication can be used in the presence of all X-10, CEBus, HomePlug or LonWorks compatible equipment with no interference between either. The UPB technology uses a completely different frequency range than any of the wide-band, narrow-band, or spread spectrum technologies. The physical method of UPB communication is entirely different than the modulation-demodulation techniques of all X-10, CEBus, or LonWorks. Higher Speed – 20 to 40 times the speed of X- 10 in terms of data transmitted. This is equivalent to over ten full commands per second. The average latency of command to action is less than 0.1 second.
* Reliability is defined as the percentage of transmitter/receiver pairs that correctly operate upon initial installation. The UPB test units are randomly installed in the environment typical of the target market. This market is defined as the single-family residential market in the US, homes with a median size of 2500 Sq, Ft. This environment is defined to be the existing base of homes, without any modifications, which means there should be no “fixing” the electrical system of the residence by adding couplers, repeaters or filtering. |
UPB technology provides an inexpensive and reliable solution for residential and commercial powerline communications applications. While other powerline communication technologies exist, none compare to UPB in cost per node, functionality and reliability.
I’ve heard quite a bit of zwave and zigbee (sp?) over the past couple of years Smarthome solution center provided a good summary of the zwave technology.