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If you want to build a ship don't herd people together to collect wood and don't assign them tasks and work, but rather teach them to long for the endless immensity of the sea. (Antoine-Marie-Roger de Saint-Exupéry)

Standard Data Types


The Object Dictionary entries in the data type section (0001h to 0FFFh) do not store any variables; they are only used for the definition of data types. If physically implemented in a node, reading these entries returns the data size of that data type in bytes, or an error if the data type is not used in the node. This mechanism allows a configuration tool to read the data types section to determine which data types are actually used in the node.

The standard data types are placed in the object dictionary for definition purposes. Data of basic type BOOLEAN attains the values TRUE or FALSE. Data of basic type INTEGERn has values in the integers. The value range is -2n-1, ..., 2n-1-1 (bit sequences of length n). Data of basic type UNSIGNEDn has values in the non-negative integers. The value range is 0, ..., 2n-1-1 (bit sequences of length n). Data of basic type FLOAT has values in the real numbers. The data type VISIBLE STRING is described in the following syntax of data and data type definitions: Unsigmed8 - Visible Char, Array of Visible Char - Visible String. The admissible values of data of type Visible Char are 0h and the range from 20h to 7Eh. The data type OCTET STRING is described in the following syntax of data and data type definitions: Array of Unsigned8 - Octet String. The data type DATE is defined as bit sequences of length 56 including ms, min, hour, standard or summer time, day of month, day of week, month, year and some reserved values. The data type TIME OF DAY represents absolute time including time in ms after midnight and number of days since January 1st, 1984. The data type TIME DIFFERENCS represents a time difference as sum of days and ms.