Control on Outside Inside Temperature Difference

[sbrink]

I would like to turn a whole house fan on when the temperature outside is lower by 5 degrees than inside. So if the outside is 75 degrees and inside is 80 I want the fan to turn on. But I also want the fan to turn on if outside is 87 and inside is 92 (for example) so I really need to control the fan on the difference of the temperatures. Also, I want to turn the fan off if the temperature outside and inside is within 2 degrees.

 

Is there anyway to calculate a temperature difference and turn things on or off? I'm new at this. Are variables something that could be used?

[Michel Kohanim]

Hi sbrink,

 

Unfortunately you cannot yet assign status values to variables. This is something we are working on for our 5.x version.

 

If you have certain temperatures in mind, you can have multiple programs for those temperatures and when status variables are available, then you can replace the logic.

 

With kind regards,

Michel

[MWareman]

Unfortunately you cannot yet assign status values to variables. This is something we are working on for our 5.x version.

 

Great to hear! I'll refrain from asking how long, I know better. Is this likely to include arithmetic on variables?

[LeeG]

By arithmetic you mean more than

Assign        $x  = a
Add           $x += a   
Subtract      $x -= a
Multiply      $x *= a
Divide        $x /= a
Remainder     $x %= a
And (binary)  $x &= a
Or (binary)   $x |= a
Xor (binary)  $x ^= a 

[MWareman]

store the result of :

 

x-y in z

x+y in z

 

Program conditions,

If x-y > z then...

 

Etc etc..

 

Especially where one or more operators came from module output from modules like weatherbug or irrigation - or even the current light level of a dimmer, light level etc etc.