Equivalent WoT TD definition

readOnly writeOnlyobservableop

Description

It represents the permitted accesslevel for a client to a property affordance.

Relevant bitfields in OPC UA are currentread (bit 0) and currentwrite (bit 1).

Thing Description provides indicators of the data model level about accessibility by the terms readOnly and writeOnly. The term observable gives an hint if the property is observable.

At the forms level the op term is used with the potential values readproperty, writeproperty, and observeproperty.

Note: per default, UA Variables are observable.

Snippet example in OPC UA (e.g., as nodeset)

…

<UAVariable NodeId="ns=1;i=35" BrowseName="1:IdealCycleTime" ParentNodeId="ns=1;i=20" DataType="UInt64" AccessLevel="3"> …

Transformed usage in a TD definition (as snippet)

…

"properties": {

"1:IdealCycleTime": {

…

"readOnly": true,

"writeOnly": false,

"observable": true,

…

"forms" : [{

…

"op": ["readproperty","observeproperty"]…