Rockwell Automation 9323-S5500D A.I. SERIES MICROLOGIX 1000 AND PLC-500 SOFTW - Manual (Page 416)

MicroLogix 1000 and PLC-500 A.I. Series Software Reference
18-6
The following screen shows edit zone markers.
Note If at least one edit marked zone appears in your program, either testing (Tst) or
disabled (Dis) appears on the status line.
Example Display with Edit Zone Markers
Replace Zone
Insert Zone
Delete Zone