 |
This example shows how KNX/Logic can implement Logic conditions with If/Then/Else actions more easily than using other KNX logic products.
This requirement is for a public toilet in a large public building eg Railway or Airport. A KNX Human Presence Counter is installed (eg https://www.steinel.de/en/sensors-profes...33200.html ), to count the number of people in the male and female toilets. The logic required is as in the flowchart below. Basically, the Fan speed is determined by the number of people detected. if the number is >5, the fan speed goes from low to medium, and if >10 the speed goes to High immediately. However if the people counted is less than 9, the fan speed goes from High to Medium after some time eg 15 minutes and if the people detected is less than 5, the fan speed goes from medium to low after eg 15 minutes. The purpose is for energy saving for a facility that is open 24 hours a day 7 days a week. This system is implemented in all the toilets in the facility, thus can result in significant energy saving in the building or buildings.
Another requirement not mentioned above is that the maximum counter of the Male and Female Toilets is used in the logic, so the logic uses the larger number based on the 2 toilets in its determination of fan speed
In Comfigurator, go Modules Tab > Controller, and the right pane with KNX/Logic Properties. Select KNX > Comfort Tab as shown below.
Add the 3 KNX objects; 1 byte Scaling Values (EIS6).
0/0/2 is the Fan speed. Map to Counter 17
0/0/15 is the 1st Toilet People Count. Map to Counter 15
0/0/16 is the 2nd Toilet People count. Map to Counter 16
Each KNX object is mapped to a Counter Register in this program. Counters are 16 bit registers in Comfort which hold values and can execute Responses, or Programs based on the counter value.
In the Counters screen below, each Counter can be assigned to a Response or program in Comfort. This allows the Response to perform logic on the counter based on the Value in the counter. Counters 15 and 16 are both assigned to the same Response.
The Response assigned to the counter is programmed in the Responses Screen (Events > Responses)
The Responses consists of Actions, The text of the Response is duplicated below:
If Counter Counter015 >= 10 Or Counter Counter016 >= 10 Then
Set Counter017(17) = 255
Stop Timer Timer01(1)
Exit Response
Else
Do Medium After 10 Seconds Using Timer01(1)
End If
If Counter Counter015 >= 5 Or Counter Counter016 >= 5 Then
If Counter Counter017 = 255 Then
Do Medium After 10 Seconds Using Timer01(1)
Else
Do Medium
Stop Timer Timer01(1)
End If
Else
If Counter Counter017 = 255 Then
Do Medium After 10 Seconds Using Timer01(1)
Else
Do LOWFAN After 10 Seconds Using Timer01(1)
End If
End If
Do Medium means Do the Medium response which sets fan speed to Medium Value.
Do LOWFAN means Do the LOWFAN Response which sets the fan speed to Low.
Timers (max 32 timers) can also be used to implement delays between actions.
Do LOWFAN After 10 Seconds Using Timer01(1) means delay for 10 seconds then do LOWFAN.. 10 second delay is used for testing so that we do not have to wait so long to test. When testing is completed, the delays can be increased to say 15 minutes.
Stop Timer means stop the timer to prevent the target Response from executing.
|
