Allen-Bradley MicroLogix 1200 Reference Manual page 361

1
System Status File
The status file lets you monitor how your controller works and lets you
direct how you want it to work. This is done by using the status file to set
up control bits and monitor both hardware and programming device
faults and other status information.
Do not write to reserved words in the status file. If you
IMPORTANT
intend writing to status file data, it is imperative that you
first understand the function fully.
C
Appendix
Publication 1762-RM001C-EN-P