Allen-Bradley MicroLogix 1200 Reference Manual page 37

User Memory
User memory is the amount of storage available to a user for storing
ladder logic, data table files, I/O configuration, etc., in the controller.
User data files consist of the system status file, I/O image files, and all
other user-creatable data files (bit, timer, counter, control, integer, string,
long word, MSG, and PID).
A word is defined as a unit of memory in the controller. The amount of
memory available to the user for data files and program files is measured
in user words. Memory consumption is allocated as follows:
• For data files, a word is the equivalent of 16 bits of memory. For
example,
– 1 integer data file element = 1 user word
– 1 long word file element = 2 user words
– 1 timer data file element = 3 user words
• For program files, a word is the equivalent of a ladder instruction with
one operand. For example
– 1 XIC instruction, which has 1 operand, consumes 1 user word
– 1 EQU instruction, which has 2 operands, consumes 2 user words
– 1 ADD instruction, which has 3 operands, consumes 3 user words
• Function files do not consume user memory.
Although the controller allows up to 256 elements in a
NOTE
file, it may not actually be possible to create a file with
that many elements due to the user memory size in the
controller.
MicroLogix 1200 User Memory
The MicroLogix 1200 controller supports 6K of memory. Memory can be
used for program files and data files. The maximum data memory usage is
2K words as shown below.
2.0K
0.5K
0K
0K
See MicroLogix 1200 Memory Usage and Instruction Execution Time on
page A-1 to find the memory usage for specific instructions.
(1) These are approximate values. For actual memory usage, see the tables in Appendix A and B of this manual.
Controller Memory and File Types
(1)
,
Program Words
4K
2-3
4.3K
Publication 1762-RM001C-EN-P