Share XAP network?

[Steve Q]

My XAP network now includes 33 devices being polled between 1 and 5 minutes. I have 5 DS2438 units that I am using to monitor the power being used by various circuits/appliances in my house. They are being polled every 5 minutes. I would like to increase the poll on some or all of these units to once per 15-30 seconds. This would improve the accuracy of the power usage data I am collecting. I have scripts that write the data to a file. I'm pretty sure if I do this I will use so much CPU/disk drive that it will completely mess up Homeseer.

So my question is: can I connect another computer to my existing XAP network to collect this data? Can I simply tap into the 1-wire network via a DS9097U? Any other method to collect data from 1-wire devices?

Steve Q

[Michael McSharry]

I poll my wattnode at 15 second intervals and that does not cause any problems and I'm certain I have much more xAP traffic than you, albeit I do have HS1 rather than HS2. For specific measurement work I run the wattnode at 2 seconds and that also is no burden for the LAN/HS. The only time you should see any LAN issues are when you stream video or similiar high bandwidth content. The stuff we do with HA DAQ/Control is a drop of water in the ocean. The processing of changes of devices states and properties through HS can place a burdenn on the CPU if data is flooded into HS.

I did do some posts in the mcsXap forum that did a stress test and collected some data when I flooded the xAP network. It has been too long for me to remember the specifics, but some searching should find this analysis. I do know that HS2/mcsXap did not scale as well as HS1/mcsXap.

You can look at the change in message count in xapmcsHub over some interval of time to get an idea of the xAP burden you do have. You can also look at instantaneous rates in the xAP Viewer.

xAP is a UDP broadcast protocol. That means that every computer that has a NIC connected to the same LAN will receive the messages simultaneously. Adding another computer does not change the utilization and marginally increases it with additional heartbeats.

If you do not want your 1-wire info on the LAN then you can use a direct HS 1-wire plugin such as the free .NET version that uses DS9097U or DS9490D, the Embedded Data Systems interfaces supported by the UltraJones plugins, or mcsTemperature. You could even use a hybrid where you split your 1-wire network between flexible vs. high rate and then use a more dedicated interface into HS for the high rate one.

[Steve Q]

Michael,

Thanks for the information. My concern is the handling of the data; I'm sure XAP can handle the transmission of huge amounts of data, but I am not so confident that Homeseer can execute the scripts I am using as fast as the data is coming in! I already see an occasional "permission denied error" when trying to save the data to disk. I should probably rethink my data storage approach; maybe use an accumulator rather than store the individual values.

Thanks for the tip about using XAPHub message count to get an idea of how much of a load XAP is carrying. I also took a look at XAP message viewer on another computer on my LAN and it showed a message rate of 112 messages per minute. Is all this activity on the LAN all the time? Or is it showing up because XAP viewer made the connection?

I'm a bit concerned if all this stuff is always present on my LAN? It may explain some of the odd behavior on my other computers!

I need to research this more.

Steve Q

[Steve Q]

I was mistaken about the poll rate of my 1-wire devices. They are being polled every 5-10 seconds. They are being captured by Homeseer every 1-5 minutes.

Steve Q

[Michael McSharry]

For some reason your xAP message rates are more that 5x the rates I'm experiencing. 1-wire polling will only generate xAP traffic when the value of the sensor changes. This will be often for the energy measurements, but I would think others are not changing that much. When you look at xapmcsHub statistics the Received column is what is going over the LAN. The Forwarded column is what is being routed internally via the fake localhost port.

Even at your data rates your LAN is barely being used for the xAP traffic. For discussion assume each xAP message is 5000 bits of data on the lan. Your rate is 2 messages per second so you are using 10,000 bits/sec on a LAN that probably has an effective throughput of 10,000,000 if you are still on a 100 Mbit NIC. This is 1/1000th of your LAN bandwidth.

I do agree with you that the CPU use at the HS end is the choke point.

[Steve Q]

Originally Posted by Michael McSharry

For some reason your xAP message rates are more that 5x the rates I'm experiencing. 1-wire polling will only generate xAP traffic when the value of the sensor changes. This will be often for the energy measurements, but I would think others are not changing that much. When you look at xapmcsHub statistics the Received column is what is going over the LAN. The Forwarded column is what is being routed internally via the fake localhost port.

Even at your data rates your LAN is barely being used for the xAP traffic. For discussion assume each xAP message is 5000 bits of data on the lan. Your rate is 2 messages per second so you are using 10,000 bits/sec on a LAN that probably has an effective throughput of 10,000,000 if you are still on a 100 Mbit NIC. This is 1/1000th of your LAN bandwidth.

I do agree with you that the CPU use at the HS end is the choke point.

Michael,

Thanks for this info, I agree that xAP traffic on the my LAN is minimal. When I set up the DS2438 units in mcsxAp1wire ver2.4.13, I used 5 second poll rates as an experiment and never changed them. Since everything is working extremely well, I never changed them to a lower rate. So, I think everything regarding xAP is currently setup so that I could get all the data I need. My question is: How could I collect the data, and store it, without using Homeseer? Is there a utility that can act as a data logger?

Steve Q