Rockwell Automation 9323-S5500D A.I. SERIES MICROLOGIX 1000 AND PLC-500 SOFTW - Manual (Page 166)

Changing Processor Modes
7-5
This
letter: Indicates this type of zone:
I Insert zone: this is a rung that has been added to the program.
D Delete zone: this is a rung that has been deleted from the program.
R Replace zone: this is a rung that has been modified. Replace zones
are always paired with an insert zone. The replace zone rung is the
old version of the rung.
For more information on edit zones and testing, refer to Chapter 18 - Online Editing
and Monitoring .
RemTest Mode
The REMote Test mode is the same as RemRun, except that outputs are not energized.
You can perform the following ladder program tests.
Single Step Test
This test mode applies to SLC 5/02 and higher processors. Use this test to verify proper
ladder operation and for troubleshooting purposes. Single Step Test initiates the
processor to scan and execute a single rung or group of rungs. See Chapter 18 - Online
Editing and Monitoring for information on running a single step test. On a SLC 5/02
processor, Single Step Test must be enabled when saving the file (see Chapter 6 -
Creating and Editing Ladder Logic ).
Single Scan Test
In this test mode, the processor executes a single operating cycle which includes
reading the inputs, executing the ladder program, and updating all data without
energizing output circuits.
Continuous Scan Test
This test mode is the same as the REMRun mode, except output circuits are not
energized. This allows you to troubleshoot or test your ladder program without
energizing external output devices.