An instance of this service interface function block type provides access to an Analog Input (AI) port.

The PORT input identifies the device-specific port to be accessed, using the generic syntax of a Universal Resource Indicator (URI).

As shown by the request_confirm service sequence below, upon the occurrence of an event at the REQ input:

1. The value of the input at the analog port is read.
2. This value is converted to a REAL value at the RD output.
   • The RD output will be in the range 0.0 to 1.0, corresponding to the minimum and maximum values of the analog input, respectively.
3. An event is then issued at the CNF output.

Other normal and abnormal service sequences are shown below.