The plug-in module of a TX-I/O module assembly can be replaced at any time by the 
same or a compatible I/O module type, even while the system is running. 
1.  Swivel the address key outward to switch off the load to the I/O module. 
  Leave the base of the key plugged into the terminal base. 
2.  Remove the plug-in module from its terminal base. 
3.  Insert the new plug-in module. 
4.  Swivel the address key back into position. 
  As soon as the new module starts communicating with the PXC Modular, PXC-36, 
or P1 BIM, it is configured according to the module address and starts operation 
shortly afterward. 
Replacing a TX-I/O Module Assembly 
When replacing a complete TX-I/O module assembly, the adjacent plug-in module on 
the male bus connector must first be removed from its terminal base. Otherwise, the 
module assembly catches on the bus connector.