Which BACnet service would you use to read multiple properties in one request?

• A. ReadProperty
• B. ReadPropertyMultiple
• C. WritePropertyMultiple
• D. UnconfirmedCOVNotification

Answer: (B)

You’re testing how to fetch several properties in one message. ReadPropertyMultiple is designed for exactly that: it lets you request multiple object-property values in a single BACnet service call, instead of making a separate ReadProperty for each property. In a ReadPropertyMultiple request you specify, for each target object, which properties you want (and optionally the array index if the property is an array). The device then returns all the requested values together, reducing network traffic and round-trips.

ReadProperty reads just one property from one object, which is fine for single-property needs but inefficient when you need many values. WritePropertyMultiple is for setting multiple properties, not reading. UnconfirmedCOVNotification is a change-of-value notification, not a read operation. So ReadPropertyMultiple is the best fit when the goal is to read multiple properties in one request. If only one property is needed, ReadProperty might be simpler, but for multiple properties, ReadPropertyMultiple is the right tool.