Omron CX-PROGRAMMER V9 - REV 12-2009 Operation Manual page 163

OMRON
Selecting OK will commit the Symbols, with changes, to the Symbol Table for checking and inserting. Selecting
Cancel will delete all the symbols in the error.
Removing Symbols
Symbols may be removed by deleting them from the symbol table.
Generally, when a symbol is removed, the program and programs using it then use the address or value of the
removed symbol.
The exception is for symbols with automatically allocated addresses – in these cases, the program shows the
name of the removed symbol in the places where it was used. It is then easy to see where an address needs to be
assigned in the program.
If the removed symbol was an override of a global symbol, then the program uses the global symbol of the same
name, which may have a different address or value.
Automatic Allocation
Automatic Allocation is a facility that enables symbols to be automatically assigned an address. This is useful
for 'work' type symbols, where the actual address is not important, providing it is unique (i.e. it is not mapped to
input or output hardware). To use this feature, it is necessary to set the memory ranges from which to allocate
these addresses. Each PLC is set separately.
The main features of auto allocation are:
♦
Multiple address allocation areas
♦
Prioritizing address allocation areas
♦
Address allocation of symbols according to type
♦
Consideration of addresses that have already been used
♦
Different Auto allocation areas for each PLC
♦
It is available to both global and local symbols
Setting Up Automatic Allocation
The PLC Automatic Memory Allocation dialog is opened from the toolbar by selecting PLC | Automatic
Allocation.
Use the following procedure to apply automatic allocation.
1, 2, 3... 1. Select (tick) the Enable automatic allocation for this PLC option.
A list of memory ranges may be entered for the PLC. The list is ordered, so that the first
area in the list is allocated first.
2. Use the Add... button to add an area to the allocation list. A dialog is shown to input the
details for the area:
3. Type in the Start address and Size (channels) to define the address range in the PLC for
CX-Programmer to allocate from.
PART 1: CX-Programmer
CHAPTER 4 – Reference
CX-Programmer _Page 83