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Zigbee for Hotel Automation.

Royston D'souza
Intellectual 866 points
Other Parts Discussed in Thread: Z-STACK, CC2531

I am working on a Zigbee Implementation for 2500 nodes. The project involves Hotel Automation.

The topolgy which I am looking for is Cluster Tree. I know that the routing mechanism is handled by the Z-Stack based on the bindings done during commissioning

There are 10 nodes in 1 room, which can be routers or end devices. Each of these nodes can be called as room devices. Each of the room devices are connected to a single room controller node within the room. All of these devices should communicate only with this room controller node.

Every room has distinctly 1 room controller node. Likewise there are 250 rooms. Each room controller should communicate with a Master Control node which is connected to a PC via a Zigbee Gateway.

The logic for communication is as below:

Out of say 10 devices in the room, 9 are switch panels and 1 is a thermostat. The switch panels may consist of 1 switch or upto 6 switches at the most. These need to communicate a key press event to the room controller only when touched by the user. Otherwise they are silent. I can see that Zigbee requires a link status to be sent at some fixed duration, but I believe this is handled by the network layer. The thermostat panels needs to report the temperature of the room every 30 secs to the room controller, which in turn reports this to the main server (pan coordinator) which is connected to a Zigbee Gateway and to a PC, where all the room temperatures are monitored. There can be some configuration file which needs to be be sent to room controllers, but this needs to be done only once during commissioning. The configuration file may be at the most 1 KB of data.

Since we are having a huge number of nodes we need to go in for S Commissioning mode. This would require us to develop a utility for commissioning. I assume we would need to make something like Ztool and use the commissioning cluster which would have to be implemented in all our devices. Please let me know if my above understanding is correct and how do I go about this if I need to develop my own tool for commissioning?

I am using the Zstack demo example. I understand that I only need to play around in the application area of the stack and configure endpoints and the rest of the communication criteria is managed by Z Stack. In the demo example provided in HA Automation example a switch sends events to a light. This requires each node to register an endpoint with the application. Once registers, we need to bind 2 communicating nodes together and then 

Besides the above, do I need to play around with Z Stack in detail, or the demo provided can be used for commercial applications. If I need to change or tune certain settings, which area in the Z-Stack do I need to focus?

Thanks in advance for your suggestions.

 

  • 0
    Mastermind 9802 points

    I would have the installer write down the serial numbers of each device in the room, and then do the commissioning on the server side; whereby the user assigns which devices to which room there. Then each device knows what other device to communicate with. Easier than device-level commissioning.

    Don't forget to have redundant Gateways; 2 per floor or so.

     

    --Derek

  • 0 in reply to Derek
    Intellectual 866 points

    Dear Derek,

    Thanks for your reply

    To follow the above commissioning method we need to use the MAC addresses of the devices and communicate with them from the server, which could be the PAN coordinator . But for this the entire set of devices will have to be connected to the server. This will happen since Zigbee will manage the MESH networking once the network is created. We would explicitly define a PAN ID and let the coordinator start the network on the selected PAN ID, the devices will join this specific PAN ID since it will be hard coded into them.

    Now we need to create a commissioning endpoint which will receive requests from server and use this endpoint for configuring the device. We need to use the 64 bit addressing mode for data transfer as this will provide an ease of installation and operation.

    In which file can I configure the following information.

    1. To explicitly use a fixed PAN ID, for ex 0x1234

    2. Ensure that Zigbee uses 64 bit addressing mode instead of 16 bit addressing.

    3. Can I create an endpoint using custom messages for commissioning.

    4. Having 2 Gateways will send duplicate ethernet Zigbee packets to the server, I assume this has to be handled in the server and discarded if redundant.

    5. We are however planning to use only a Gateway near the server. I assume with the method of using Gateways per floor, we may need to have Wifi connections established through access points per floor. Is this what you were recommending.

    Regards

    Royston

  • 0 in reply to Royston D'souza
    Intellectual 866 points

    Also to add to the above, I am planning to use pre configured security keys stored in all the devices. Currently this will be implemented in the first phase without complication of using a trust center and link key.

    If this security key is not shared with anybody besides our team, then is this method more rugged than acquiring keys on joining a network. As in the later the key is delivered to the device unsecurely and a packet could be sniffed to decode the secureity key during this request.

    Regards

    Royston

  • 0 in reply to Royston D'souza
    Mastermind 9802 points

    Hello,

       I wouldn't hard code the PAN, since you're going to have multiple coordinators (Gateways) in the hotel, let the devices join whichever PAN is the strongest.

    Also, instead of sending duplicate messages to the Gateways, have both available. If one goes down then the Zigbee devices should restart and join the other (working) gateway.

    Is this for a commercial product?

     

    --Derek

  • 0 in reply to Derek
    Intellectual 866 points

    Hi Derek,

    I believe when you say have multiple coordinators per floor, means have individual Zigbee networks working on different PAN's per floor. So there will be exclusively 1 PAN coordinator per floor which will also be a Zigbee gateway. If there are 10 floors the central server will receive messages from a minimum of 10 IP addresses.  So for 20 rooms per floor (10 floors for 200 rooms) I would have a gateway which would then connect the server through a WIFI access point. I believe this what you are suggesting. Please correct me if I am wrong.

    What I intend to do is the following.

    1. Ship the devices with an Fixed Set of Network Attributes and a commissioning Extended PAN ID specified by the Zigbee Alliance for Commisioning

    2. Once the devices are installed, note down their MAC Id's (Serial No's) depending on which room they are installed etc.

    3. Set up a network for 1 room using a commissioning tool using the CC2531 dongle and PC ZAP commands.

    4. Set up Binding of the room devices (routers or end devices) to the room controller (router) using serial numbers. The lamp loads will be connected to the Room controller and the devices are the switches to operate them. So they will share a matching Cluster Ids for endpoints to support binding.

    5. Similarly set up the other room devices and room controllers and bind them

    6. After the bindings are established using the commissioning tool, move all the devices to the operating network, which will now have the Gateway as the coordinator.

    Question:

    You have suggested a gateway per floor. Is it not possible to just use a single or maybe 2 gateways for an entire installation. Mostly the switches are silent end devices and will only be transferring data if a user touches them. Also the data will only have to be routed to the corresponding room controller. Ideally only 200 Room controllers will be connected to the Gateway. Please note no room devices will need to speak outside the room. The Room controller has to report room temperature every minute to the Coordinator (Gateway) so that the 3rd party HVAC can controlled through BACnet. The room controller also reports events such as Window open, Door Open etc when the event occurs. Actually speaking there is not going to be heavy traffic as noticed in Industrial Sensing Environments.

     

    Yes, This is for a commercial application. 

     

     

     

     

  • 0 in reply to Royston D'souza
    TI__Genius 10650 points

    Hello Royston,

    In the Z-Stack-2.5.0 install please see the document Z-Stack Commssioning Cluster API, Z-Stack sample application (pg 17) and see the sample application on how to use commissioing cluster for network deployment. This should help you in deploying your network and should answer most of your question.

    You can find the document after installing Z-Stack-2.5.0 from www.ti.com/z-stack  at   -  C:\Texas Instruments\ZStack-CC2530-2.5.0\Documents

    Regards,

    Suyash Jain

  • 0 in reply to Suyash Jain
    Intellectual 866 points

    Dear Suyesh,

    Thank you for your reply. 

    For the above configuration of 2500 nodes, all my devices are powered i.e. I dont have any battery operated device.

    1. Can I implement all of the 2500 nodes as routers. Will this aid in creating a robust mesh network as each node can now route a packet.

    2. Will all the routers keep sending a Network Link Status packet. If so can I delay this as compared to Sample Zstack app so that I dont have 2500 messages being transmitted every 15 secs. If so what is the max time that can be set for Network link status

    3. From Zigbee specification the Max depth of can be 6. Does this mean that my PAN Coordinator can be just 6 hops 

    4. Once I power the 2500 routers, since the Z stack will setup the network (PAN Coordinator), do I need to place the coordinator at a specific location so that network depth is maintained or can I place it for instance on the Ground floor, where the total floors may be 10. Does the mesh network form by itself once the EPID's are set same and all devices support joining since they are routers. 

    5. Can I power all the 2500 nodes at a time during the formation of the network or I would need to do this room by room basis.

     

    Regards

    Royston