CODESYS as an industry standard
CODESYS (Controller Development System) is developed by 3S-Smart Software Solutions and is one of the most widely licensed PLC runtime environments in the world. Rather than building their own from scratch, many PLC manufacturers license CODESYS and adapt it for their hardware.
The result is that knowledge of IEC 61131-3 programming within the CODESYS environment transfers across a significant portion of the industrial control hardware market: Beckhoff TwinCAT, Phoenix Contact PLCnext, Wago PFC, Bosch Rexroth ctrlX, and many others share the same fundamental programming model.
IEC 61131-3 programming languages
CODESYS supports all five IEC 61131-3 languages: Ladder Diagram (LD), Function Block Diagram (FBD), Structured Text (ST), Sequential Function Chart (SFC), and Instruction List (IL, now deprecated). Structured Text is the most capable and readable for complex logic; Ladder is most familiar to electricians and maintenance personnel. We program in the language that best suits the application and the team who will maintain it.
OPC UA and modern connectivity
CODESYS platforms typically include an OPC UA server capability, making data accessible to SCADA systems, historians, and edge computing platforms without proprietary middleware. Combined with IEC 61131-3 programming and open connectivity, CODESYS-based controllers are a practical choice for sites building toward more connected OT infrastructure.