Controlling Automation Rules with RS232 Humidity Devices

Tips and Techniques for using MLServer's Automation Rules
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jonreid
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Controlling Automation Rules with RS232 Humidity Devices

Postby jonreid » Thu Nov 06, 2008 10:07 pm

Who can assist me in this issue.

The problem is that i have a RS232 based temp/humidity sensor which reports and updates a MLServer temp variable every x number of seconds.

The problem is that when the device reaches a critcal number say 75% then i want it to do something, say start a fan. This is no issue.

But when the rule is setup to trun the fan off under 75% it does not work. The problem is that it continues to fire on each time the temp variable changes below 75%. This is because the rule i am using is whenever the x value changes and is less than the 75% then do x.
Well x is turn off, so each time below 75% when the temp or humidity chages the rule keeps trying to turn the fan off for instance. This causes a lot of overhead and perhaps also turns the fan off when you actually want it on via a wall panel or similar.

How does cinemar handle a one shot execution of an event on it occuring. It appears the issue is that the actual trigger of the rule is the problem in that if the trigger was only execuited when the temp got to say 74% that would be ok but the temp variable may not actually write 74% into the variable as the temp is only checked every 30-60 seconds.

This is a problem and i do not know how to overcome it. I have tried countless rules variations with no such luck.

Over to the experts and pros..
Thanks

Jon
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ricks
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Postby ricks » Thu Nov 06, 2008 11:10 pm

No expert here but why not use 2 automation rules.

The first automation rule would be "whenever {{humidity}} is less than 75 AND {{fan}} is ON then "turn fan off"

The second would be "whenever {{humidity}} is greater than 74 AND {{fan}} is OFF then "turn fan on"

You may want to add a few degrees to the conditional so you don't get "fan bounce".

HTH
Rick

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jonreid
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Postby jonreid » Thu Nov 06, 2008 11:56 pm

Rick

Great thinking, thats what i was after, i will test and let you know, thanks heaps its much appreciated.
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