Dallas One Wire

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Hi

Whilst the Dallas One Wire system is very good and simple to install it does seem to suffer from loss of connection to either one sensor or the whole network, to fix its just a matter of stopping and restarting the data source. Is there a way to do this if an alarm is raised or say hourly ?

Thanks

Keith

Hi Keith,

In the current version data source restarts are manual processes only. In any case, our preferred fix for the situation would be - if it is the data source that is the problem - to fix the data source. Can you describe the conditions around which the failure occurs? Anything that may lead to a problem theory could be useful:

• does the problem always happen at a particular time, or after a particular period of operation?
• is it caused by particular point values? (Perhaps turning on a certain piece of equipment causes a voltage drop and subsequent communication problems?)
• etc.

I totally agree with your approach but

The rs232 connectors seem to work differently, some are more resilient to network issues than others (Link ones seem better). Over time I've become convinced the weather makes a difference, high humidity etc.

Dallas have this article http://www.maxim-ic.com/appnotes.cfm/an_pk/148 Guidelines for Reliable 1-Wire Networks
which talks about getting reliability but also shows how complex it can be to resolve. Just restarting normally gets it going again.

Unfoutuantly I'm not an electronics engineer so the level of testing suggested is currently beyond me, if i start using mango to running my house i may have to learn how so the heating comes on in the morning and i don't get moaned at !!!!

:) Fair enough. It is certainly possible to append a scheduled restart parameter to the data source. Perhaps we can consider this for the next micro release.

Can you describe how often failures happen? Are they regular or random? Roughly how much time elapses between failures?

Take last night or instance, I moved a humidity sensor from one circuit to another. For the whole evening the circuit worked intermittantly. Sometimes it would not even admit the circuit was there sometimes only seeing 9-10 sensors. I left it overnight and restarted it this morning and its working fine now doing a check every minute.

This is not a problem with Mango, its a onewire issue, my setup has always done it but stopping and restarting generally cures it.

So its not predictable, is there any way I can see the error messages ?

Rgds

Keith

Ok, i understand.

By error messages i mean the messages provided by the events raised by data source failures. Do you receive and urgent alarms? You would see them in the Events page. Try clicking "Show inactive alarms" to look for inactive ones.

Thanks for putting in the rescan feature for one wire, its made a huge difference.

Keith

Glad to hear. Thanks for the feedback Keith.