The Dry Contact is a useful device for creating custom low-level integrations with systems that don't have a direct way to communicate with Nero. For example, a very common application is to trigger the opening, closing, or stopping of a garage door or gate with a quick pulse of the output. The Dry Contact works so well in these scenarios because it does not have the relay linked with the power feed, allowing you to switch a different voltage device or use it as a no-voltage contact.
The default configuration of the Dry Contact means it will latch into either state when you interact with it, similar to a standard Relay. Just like the standard Relay, the Dry Contact has a series of parameters that can help us modify the behaviour of the unit.
Configure the dry contact for momentary actions
This article assumes the relay is in the default Normally Open (NO) state. If you have changed this you will need to use the appropriate parameter for your use case.
For this article, we are going to assume that your device requires a 1-second pulse to trigger. If you require longer times you can set the parameter as appropriate. If you need a shorter, or more specific time, refer to Parameter 15 which will allow you to set this time into milliseconds from the default seconds.
- Go to the Device Page.
- Select Device Options.
- Locate parameter 11 or add a new configuration line using the buttons on this page.
- Set parameter 11 to 1 in the desired value column.
- Click Save Changes below the list of parameters. This process can take up to 90 seconds to complete depending on the complexity and business of your mesh network.
To confirm the setting is correct, trigger the relay from the UI or a wall switch. You should see that the output turns on for one second and then turns off again.
Why use parameters and not a scene?
You can create similar behaviour using the scene builder in Nero, however, we always recommend using parameters for enforced behaviour. This will ensure that the device always acts as a momentary trigger, even if the Nero gateway is offline when the device is triggered (for example, from the wall switch).