Overview The following provides information on the front panel topology of the Quantum CPU
modules. There are two switches (a three-position slide switch and a three-position
key switch) located on the front of the 140 CPU 434 12A, 140 CPU 534 14A, and
140 CPU 534 14B modules. The 140 CPU 311 10 module has two slide switches
but does not have a key switch.
Front Panel Slide
Switches
The 140 CPU 311 10 module has two, three-position slide switches. The left switch
is used for memory protection when in the top position and no memory protection in
the bottom position. The three-position slide switch on the right is used to select the
communication parameter settings for the Modbus ports.
The 140 CPU 434 12A, 140 CPU 534 14A, and 140 CPU 534 14B modules have a
single slide switch that is used to select the comm parameter settings for the
Modbus (RS-232) ports.
The following illustration shows the slide switches for these two modules. The 140
CPU 311 10 uses both slide switches. The 140 CPU 434 12A, 140 CPU 534 14A,
and 140 CPU 534 14B modules use only the slide switch on the right.
Setting the slide switch to the top position assigns ASCII functionality to the port; the
following communication parameters are set and cannot be changed.
Note: The CPU hardware defaults to bridge mode when the front panel switch is
set to RTU or ASCII mode. When networking controllers, a panel device connected
to the CPU Modbus port can communicate with the controller to which it is
connected, as well as log into any nodes on the Modbus Plus network.
