IEC 61131-3 - Data Types

Data Types

• Bit Strings - groups of on/off values
  • BOOL - 1 bit
  • BYTE - 8 bit
  • WORD - 16 bit
  • DWORD - 32 bit
  • LWORD - 64 bit
• INTEGER - whole numbers
  • SINT - signed short (1 byte)
  • INT - signed integer (2 byte)
  • DINT - double integer (4 byte)
  • LINT - long integer (8 byte)
  • U - Unsigned - prepend a U to the type to make it unsigned integer.
• REAL - floating point IEC 559 (IEEE)
  • REAL - (4 byte)
  • LREAL - (8 byte)
• TIME - duration for timers, processes.
• Date and Time of day:
  • DATE - calendar date
  • TIME_OF_DAY - clock time
  • DATE_AND_TIME: time and date
• STRING - character strings surrounded by single quotes.
  Escaped characters are preceded by a dollar sign.
  ($$ $' $L $N $P $R $T $xx) => ($ quote linefeed newline page(FF) return tab hex_value)
  • WSTRING - holds multi-byte strings.
• Arrays - multiple values stored in the same variable.
• Sub Ranges - puts limits on value i.e., (4-20) for current
• Derived - type derived from one of the above types.
  • TYPE - single type
  • STRUCT - composite of several variables and types.
• Generic - groups of the above types:
  • ANY
    • ANY_DERIVED
    • ANY_ELEMENTARY
    • ANY_MAGNITUDE
      • ANY_NUM - LREAL, REAL
      • ANY_INT - LINT, DINT, INT, SINT, ULINT, UDINT, UINT, USINT
    • ANY_BIT - LWORD, DWORD, WORD, BYTE, BOOL
    • ANY_STRING - STRING, WSTRING
    • ANY_DATE - DATE, TOD, DT