Chapter 3. Program Data
56 PACSystems* RX7i, RX3i and RSTi-EP CPU Programmer's Reference Manual GFK-2950C
3.10.3 UDT Limits
â–ª Maximum number of UDTs per target: 2048
â–ª Maximum UDT size: 65,535 bytes
Note: Bit spares created to line up the end of a section of BOOL variables or arrays with the end of
a byte will count toward the maximum size.
â–ª Maximum number of top-level UDT elements: 1024
â–ª Maximum array size of a top-level UDT element: 1024 array elements
â–ª UDTs do not support the following:
- Two-dimensional arrays
- Function block data types
- Enumerated data types
â–ª You cannot nest a UDT of one memory type in a UDT of a different memory type.
â–ª You cannot alias a variable to a UDT variable or UDT variable element.
â–ª A FAULT contact supports a BOOL element of a UDT I/O variable, but not a BOOL element of a
UDT parameter in a UDFB or parameterized block.
â–ª POSCON and NEGCON do not support BOOL elements of UDT parameters in parameterized
blocks or UDFBs.
3.10.4 RUN Mode Store of UDTs
An RMS can be performed on a target that contains a variable of a UDT, unless:
â–ª An operation in the UDT editor modifies the offset or bit mask of an element that has the same
name before and after the operation.
â–ª The size of the UDT definition increases.
â–ª Array length increases.
â–ª The memory type of the UDT definition changes.
â–ª There is a data type change in the UDT definition, except for the following interchangeable data
types:
- WORD, INT, UINT
- DWORD, DINT
â–ª The UDT definition is renamed.