The Priority Write action determines the values to write at priority level to a variable on a device. There are sixteen levels of priority in BACnet, known as the Priority Array, which consists of commands or NULLs. The active command is the one with the highest priority (lowest array priority level) with a non-Null value. If a priority level holds a value of NULL, then the next non-NULL object becomes assigned to the object.
Writing a value to the present property of a BACnet Analog, Binary or Multistate point, requires a priority between 1 to 16 to be specified with a nullable value.
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Parameters
| Parameter | Description |
|---|---|
| Type to Write | Type of value to be written - Analog,for things like temperature; or Binary. |
| What to Write | Determines whether you want to write Values or a NULL. Clearing a value is accomplished by writing a NULL value. |
| Priority Level | The priority level to write the value at. Must be in the range [1...16]. |
| Device Name | The name of the configured BACnet/IP device instance to write to. |
| Variable Name | The name of the configured BACnet/IP device variable to write to. |
Input tab
| Parameter | Description |
|---|---|
| FloatValue | The value read from the device variable. |
| Device Name |
The device where the variable resides. The name can be a constant, or it can be dynamically specified. The default value is the substitution variable, $(Device Name). Thiscan be used along with the Input tab parameter Device Name, or it can be changed. The parameter lets you specify the name of a device using a compound string. |
| Variable Name |
The variable to read. The name can be a constant (entered directly in the parameter), or the name can be dynamically specified. The default value is the substitution variable, $(Variable Name). This can be used along the Input tab parameter Variable Name, or it can be changed. The parameter lets you specify the name of a device using a compound string. |
You can also use the workbench to do on demand writes to BACnet objects. The priority is taken from the channel, as you can see below. Using this approach, you cannot specify a node value.
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If you do a write using the workbench, the priority is taken from the Write Priority set on the Bacnet channel, making it possible to personalize and set the devices behavior in a better way.