Enhanced redundancy and high availability applications are provided in ControlLogix firmware version 19.50. Details of the firmware package (V19.52Enh) can be downloaded from Rockwell Automation's technical support website. ControlLogix Redundancy v19.50 adds support for:
GuardLogix System 1756-M13 1756-M13
GuardLogix controllers are ControlLogix controllers that also provide control. The GuardLogix system is a dual-controller solution—you use the 1756-L6xS or -L7xS primary controller and the 1756-LSP or L7SP partner to achieve SIL 3 and Cat. 4/PLe. A major advantage of this system is that it remains a single project and standard. Controllers that are part of the system are automatically configured and require no user setup.

Alternative brand: ABB RLM01 (Order number: 3BDZ000398R1) Industrial-grade design, adaptable to a wide range of field environments.
PROFIBUS Redundancy Link Module for cable redundancy
Overview:
This product is a PROFIBUS DP protocol fieldbus redundancy link module that enables mutual conversion between single bus and redundant dual bus. It can convert a single-cable bus into a redundant Profibus DP bus, or convert a redundant Profibus DP bus into a single-cable bus. The DIP switch allows setting the rate or optional rate adaptation. It supports 10 common rates of the Profibus DP bus. Shenzhen Xunji Technology Co., Ltd. is a provider of industrial network equipment. The devices adopt new technologies and independent intellectual property rights, introducing innovative features in the industry.