Allen-Bradley 1769-ASCII Installation Instructions Manual page 11

Replace a Single Module Within a System
The module can be replaced while the system is mounted to a panel or DIN
rail.
1. Remove power.
Remove power before removing or inserting this module. When
ATTENTION
you remove or insert a module with power applied, an electrical
arc may occur. An electrical arc can cause personal injury or
property damage by:
• sending an erroneous signal to your system's field devices,
• causing an explosion in a hazardous environment
Electrical arcing causes excessive wear to contacts on both the
module and its mating connector. Worn contacts may create
electrical resistance.
2. On the module to be removed, remove the upper and lower mounting
screws from the module (or open the DIN latches using a flat-blade
or Phillips-style screwdriver).
3. Move the bus lever to the right to disconnect (unlock) the bus.
4. Move the bus lever on the right-side adjacent module to the right
(unlock) to disconnect it from the module to be removed.
5. Gently slide the disconnected module forward.
If you feel excessive resistance, check that the module has been
disconnected from the bus, and that both mounting screws have been
removed (or DIN latches opened).
You may need to rock the module slightly from front to back to
remove it, or, in a panel-mounted system, to loosen the screws of
adjacent modules.
causing unintended machine motion
Compact 1769-ASCII Module 11
Publication
1769-IN068B-EN-P - May 2005