PMS Variable Services, such as Read and Write are used to transmit PMS variable data.
These variables can have different data types:
-
Integer or Unsigned integer,
-
Double integer, Double unsigned integer or Real,
-
String,
-
Structures.
These variable data must be passed to the IBS (or are received from the IBS) in a special format, which is defined by the PMS/FMS Encoding Rules. In this data format the Most Significant Byte (MSB) of an Integer or Double integer comes first.
In general rule, you need to know exactly, how the data is structured in the PMS Encoding Rules, then the high byte and low byte of each word must be reversed. If the data length is not even, the last byte will be stored in the LSB of the last data word.
If only simple data types are exchanged, the Control Expert representation matches the usual Control Expert representation of this data type. When structures or arrays are used, however, it can become very complicated.
The figure below is a representation of data types such as Integer and Unsigned integer:
The figure below is a representation of data types such as Integer and Unsigned integer:
The figure below is a representation of data types such as Double integer, Unsigned double integer and Real:
The figure below is a representation of data types such as String:
The figure bellow presents representation data types such as structure. The structure consists of:
