Rockwell Automation T3420AF ICS Regent Analog Input Modules - Manual (Page 24)

Analog Input Modules (T3420A, AF)
2 4
Industrial Control Services
Keying
The I/O chassis can be physically keyed to prevent accidental
damage caused by inserting a module into a slot wired for a
different module type. Figure 14 illustrates how the slot keys
are installed on the I/O chassis slot field wiring connectors.
The slot key positions for the analog input modules are listed
in Table 5.
Figure 14. Installing Slot Keys.