1. Set up
2. Configuration
   1. Sentinel Value Properties
   2. Sentinel Value Types
   3. Sentinel Comparison Types

A sentinel is an indicator of the presence of an issue or error.

Some physical devices use specific values to denote that an issue occurred when it tried to read the actual value.

Sentinel Manager is used by the device to detect these values in the properties and translate them to the correct error message. The manager maintains a list of Sentinel sets, where each set has one or more values and associated error descriptions.

Set up

Add the following NuGet packages:

• IoTnxt.Raptor.TransformManager
• IoTnxt.Raptor.SentinelManager
• IoTnxt.Raptor.Common.Async

In the Program.cs file of the AspNetCore service, add the following lines in the CreateHostBuilder method:

    .AddRaptorDevice()
    .AddObjectCache<ITransformState>()
    .AddRaptorTransformManager("TransformSets", (services, configuration, builder) =>
    {
        builder.AddSentinelFunctions(services, configuration);
    }

Configuration

Configuration of the various transformations is done via a configuration file in the /config folder. An example configuration file is shown below:

{
  "SentinelOptions": {
    "Sets": {
      "SentinelSet1": {
        "Sentinels": {
          "FFFF": {
            "Value": 65535,
            "ValueType": "Int32"
            "Error": "Unimplemented"
          },
          "FFFE": {
            "Value": 65534,
            "ValueType": "Int32",
            "Error": "Over measurable range"
          },
          "FFFD": {
            "Value": 65533,
            "ValueType": "Int32",
            "Error": "Under measurable range"
          }
        }
      }
    } 
  } 
}

Sentinel Value Properties

Sentinel Value Types

Sentinel Comparison Types