Rockwell Automation 9323-S5500D A.I. SERIES MICROLOGIX 1000 AND PLC-500 SOFTW - Manual (Page 23)

MicroLogix 1000 and PLC-500 A.I. Series Software Reference
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You can prevent users from exiting temporarily to DOS by setting the NOEXITTODOS
environment variable. See the A.I. Series Installation Guide for a complete list of
environment variables.
Add the following line to a batch file that starts PLC-500 A.I. or to the
AUTOEXEC.BAT file. If you only want to prevent exiting to DOS for one use, type
the line at the DOS prompt before starting PLC-500 A.I.
SET NOEXITTODOS=1
You can also use the security system to prevent users from exiting temporarily to DOS.
See Chapter 20 - Security System .