Pulsing a load on and off.

Hi all. I have a customer that has requested to be able to pulse a ceiling panel heater on and off as a form of temperature control ie. on for 2 minutes, off for 1 minute and repeat. The installation has a colour touch screen and the heater will be controlled by a relay channel. It would be nice if the user could adjust the pulse on and pulse off times via the touch screen as well. Can anyone recommend the best way of doing this.

 

One solution:

Create a new SystemIo integer called 'Heater' and set range 0-100%

In logic:

Code:

In Advance/Constants add:

HeaterCycleTime = 180 ; //Seconds between heater cycles

In a new module:

if GetIntSystemIO("Heater") > 0 then
   PulseCBusLevel("Local", "Lighting", "HeaterGA", 100%, "0s",
         GetIntSystemIO("Heater") * heaterCycleTime div 100, 0%);
Delay(HeaterCycleTime);

Add a slider to a page and set it to systemIO 'Heater'
Add a level under the slider and set to same systemIO

Moving the slider will adjust the on/off percentage within the set cycle time

If you turn it off it will turn off at the end of the current period. If you want it to go off immediately (or respond immediately to set point changes) it will get a (little) bit more complex.