Bradley Smoker PLC-5 user manual 12Addressing I/O and Controller Memory

4-12Addressing I/O and Controller Memory

TIP

You might also want to leave room for future expansion when grouping data. Do this by leaving gaps between:

•data blocks within a file

•groups of sequentially numbered files

•modules in an I/O chassis

IMPORTANT

If you plan to edit your program online in Run mode, you must allocate unused data table files/elements and program files because you cannot create user memory while in run mode. Each unused file, however, uses 6 words of overhead memory for each data/program file you skip. Use care when leaving gaps.

TIP

Follow these guidelines when organizing data files:

•Group large amounts of related data into files.

•Address the data files from 3-999 as needed. (See on page page 13).

•Address the words needed in each data file consecutively from 0-999 (0-1999 for some data types in series E, revision D controllers and later).

•Address the words of I/O image data according to how you configured your I/O:

–0-37 (octal) for PLC-5/11, -5/20, -5/20E

–0-77 (octal) for PLC-5/30

–0-177 (octal) for PLC-5/40, -5/40L, -5/40E

–0-277 (octal) for PLC-5/60, -5/60L, -5/80, -5/80E

•When addressing I/O image bits, address them 00-07 or 10-17 (octal).

•When organizing bit data, address the bits in each word 0-15 (decimal) for binary or integer files.

Each data table file allocates 6 words of memory when you create the file. This is in addition to any data stored in the file.

Publication 1785-UM012D-EN-P - July 2005