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Software Algorithm

The wall switch allows control of lights and other controllers via the BACnet network.

Button​

The functions of the physical buttons are configurable. When a button is pressed, the associated logical dimmer acts according to the configuration.

Dimmer​

The wall switch integrates four (4) logical 0-100% dimmers. Any physical button of the wall switch can be associated with any dimmer.

LED Indicators​

Each button has a backlight LED. By default the LED follows the local dimmer feedback, but it can also be controlled over the BACnet network.

For each LED, the wall switch provides an INDICATOR Binary Value object for simple on/off control and an INDICATOR PATTERN Multi-State Value object to select a behavior such as a blink or a pulse. When the network writes to either object, it takes control of that LED; the last write wins. Setting the INDICATOR PATTERN back to Auto releases the LED so it resumes following the local dimmer feedback.

While the wall switch is being identified, the network control of the LEDs is suspended so the identification can be seen clearly.

Notification​

When the current dim level of a dimmer is modified from a button, the wall switch can send a notification to the lights or the controllers.

COV​

The wall switch sends a BACnet COV notification, ConfirmedCOVNotification, message to the subscribed controller.

Write Property​

When a change in the dimmer current value occurs, the wall switch can write the new value with the BACnet WriteProperty service to the configured object of the controller.

Write Group​

The wall switch can send a BACnet WriteGroup message to the configured destination.

Each dimmer has a (1) associated Channel object and up to three (3) Control Groups. Only the first Control Group is used to send the notification with WriteGroup, but WriteGroup messages are received for all three (3) Control Groups.

When there are multiple wall switches in a zone, we might want them to follow each other, so that the dimmer value is the same on all wall switches of the zone. This way the LED indicator shows the correct value for all wall switches. For this, they must use the same Channel and Control Group numbers.

Presently this wall switch is the only product from Cristal Controls to support the BACnet WriteGroup service and the Channel object.

Polling​

An external controller can read the current value of the dimmer with the BACnet services ReadProperty and ReadPropertyMultiple.

Settings​

The wall switch settings are done using the Config.bin file available from the BACnet network. This BACnet file is changed with the BACnet Browser software.