The video below goes over how one can create a Sensor Trigger to control an HVAC Unit's Cooling Stage (Dry Contact) within Portal 2.0. This video and others can be found at our Growlink University webpage.
Audio Transcript:
Hey, this is Josh with Growlink, and in today's walkthrough we'll be going over how to make a sensor trigger that engages a cooling stage on an HVAC unit when it's set up as a dry contact.
A dry contact is just sourcing voltage from the unit that gets passed back towards the unit when that relay is engaged.
In those kind of setups, directly controlling an output on the controller turns the HVAC unit’s cooling stage on and off.
To make this sensor trigger to turn on that HVAC units cooling stage and off based on the temperature in the room, we'll need to make a sensor trigger on the controller the dry contact relays are registered to.
We'll start by logging into Portal 2.0 and selecting the controller that we want to make it on.
In this example, we only have a single controller, so we're going to go to this example controller here.
Once at the dashboard, we're going to hit the rules section up at the top of the page.
In the rules sub page we're going to click the default folder and the default rule group to make this rule in.
Since we want this output to turn on and off based on the sensor data within the room, we're going to use a sensor trigger by clicking the Sensor Triggers tab and hitting Add Sensor trigger.
In the pop up the follows, we're going to put in a display name so we can easily identify this rule, such as example Cooling stage rule.
Next, we're going to select a time of day. We have a couple of different options here, all day, day only, night only, and custom time. In this case we're going to choose all day, so at any time the room gets above some certain value, it engages the cooling stage of the HVAC unit.
Next, we want to choose what sensor we want to associate with the activity of this rule.
In this case, we want to look at the room temperature so it's able to turn on based on the temperature of the canopy of plants.
Next, we want to choose what device we want to turn on. here we can see we have 4 outputs total. one is the first cooling stage of a unit, the second cooling stage of the unit, and then the two heating stages of the unit. In this case, we're just going to select the first cooling stage.
As for the next value, determining if the set point is dynamic or static. Static is the most straightforward way to set up these rules, as it will consistently trigger at one specific value and turn off at a specific value.
Next, we want to specify the value at which we want this cooling stage to turn on, and in this case we can specify say 80°.
Next, we want to specify the dead band around this value, and we can specify a dead band of say 2°.
Next, we want to specify the activation point. Since this is engaging the cooling stage of an HVAC unit, we want to use the above set point so that as the temperature goes above a specified value, it turns on this cooling stage, then when it goes below a specified value, it turns off this cooling stage.
Here you can see with this data populated that there's a rule logic summary sentence that populates as well as a graph displaying the logic attempting to be employed.
In this case, the cooling stage will get turned on for at least 2 minutes when the room temperature exceeds 82°F and switched off when it returns to 78°F.
It's important to note that when devices are set up as an air conditioner or a heater that the minimum runtime advanced sensor option is automatically set to two minutes and this is set that way to prevent the compressor on the unit from short cycling. This ensures the unit always runs for at least 2 minutes to prevent that short cycling, and if you mouse over this icon, it'll explain exactly why it's set that runtime.
With these values set in place, all the one needs to do is hit the Add Trigger button, followed by updating the controller with this newly configured rule, by tapping the Update Controller button.
This concludes how you would make a sensor trigger to turn on the cooling stage of an HVAC unit when it's set up as a dry contact within Growlink Portal 2.0.