MQTT topic names

Note: This section is not applicable to MQTT Sparkplug-based subscription model.

Items subscribed to an MQTT broker are known as topics. MQTT data sources use topic names for sending and receiving messages. A topic name can be divided into multiple topic levels. Each level is separated by a forward slash (/). Wild cards are not supported for MQTT topic names in this release.

The following rules apply to topic names:

• Must be at least once character in length

• Names are case sensitive

• Space character is valid and can be included

• Names can include a leading or trailing forward slash, but the forward slash counts as an identifier (/a, a/ and a are all different topic names)

• '/' is a valid topic name

• Topic names cannot include the null character (U+0000)

• Topic names are UTF-8 encoded strings. The maximum encoded length is 65535 bytes

  Note: In general, MQTT supports the usage of "+" as a single level wild card and "#" as a multi-level wild card. However, the AVEVA MQTT Communication Driver does not currently support usage of wild cards.

Syntax Example

site/area1/mixer4/valve/input