Allen-Bradley ControlLogix 1756-DH485, User Manual, Page: 12 / 110

Publication 1756-UM532A-EN-P - May 2006
1-4 1756-DH485 Module Overview
Removal and Insertion
Under Power
You can install or remove the module while chassis power is applied if you
observe the following precautions.
WARNING
!
When you insert or remove the module while backplane
power is on, an electrical arc can occur. This could cause an
explosion in hazardous location installations.
Be sure that power is removed or the area is nonhazardous
before proceeding. Repeated electrical arcing causes
excessive wear to contacts on both the module and its
mating connector. Worn contacts may create electrical
resistance that can affect module operation.