Pls notice as below when inquiry:
 1756 ControlLogix Controllers
 The ControlLogix® controller provides a scalable controller solution that is capable of addressing many I/O points. You
 can place the ControlLogix controller into any slot of a ControlLogix I/O chassis, and install multiple controllers in the
 same chassis.
 ControlLogix controllers can monitor and control I/O across the ControlLogix backplane, and over network links. The
 ControlLogix 5580 controllers have an embedded Ethernet port for a direct connection to Ethernet-enabled devices and
 networks, and also support communication interface modules in the local chassis. To provide communication for
 ControlLogix 5570 or ControlLogix 5560 controllers, install the appropriate communication interface module into the
 local chassis.
 ControlLogix 5580 and ControlLogix 5570 controllers are available with a conformal coating. A conformal coating
 provides a layer of protection against contaminants and humidity to help protect the assembly and extend product life in
 harsh, corrosive environments. Products with a conformal coating have a ‘K’ suffix at the end of the catalog number.