Omron SYSMAC C500 Installation Manual page 31

Assembly
Unlike the CPU of the Package-type PC, the CPU of the Rack PC has no I/O
points built in. So, in order to complete this kind of PC we need to mount one
or more I/O Units to the Backplane. Mount the I/O Units to the Backplane by
pressing the I/O Unit firmly into position, making sure the connectors are
properly mated. Secure the Unit by tightening the mounting screws located
on the top and bottom of the Unit.
The figure below shows one I/O Unit mounted directly to the left slot of the
CPU Rack.
I/O Unit
I/O Units are where the control connections are made from the PC to all the
various input devices and output devices. As you can see from the figure,
there is still some space available on the right side of the Backplane. This
space is for any additional I/O Units that may be required.
The figure above shows a total of eight I/O Units mounted to the Backplane.
Backplanes are available in different lengths, and can hold a different number
of I/O Units accordingly. Of course, not all I/O Units look exactly alike, but the
ones in the figure show their typical appearance. This configuration of Back-
plane, Power Supply, CPU, and I/O Units is called a CPU Rack. This term
refers to the Backplane and all the Units mounted to it. However, if we want
to include more than eight I/O Units in our configuration we can add an addi-
Section 3
Mounting screws
Provided at the top and
bottom of the Unit
Connector
Make sure the connectors
are properly mated.
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