PLC & RTU Programming and Logic Development

We build new applications, clean up existing ones, and migrate legacy code to modern, standards-based architectures, always with clear documentation and a lifecycle mindset.

Reliable control starts with solid logic. CueBid Automation designs and programs PLC and RTU applications that are stable, maintainable, and easy to troubleshoot—across multiple vendors and platforms.

Programming Languages We Support

We work with all major IEC 61131-3 control languages, selecting the right mix for the application and the client’s standards.

  • Ladder Diagram (LD)
    Ideal for discrete logic and easy for technicians to follow. Commonly used for interlocks, permissives, and straightforward sequencing.

  • Function Block Diagram (FBD)
    Excellent for analog control, PIDs, and reusable control blocks. Helpful where process engineers need a visual view of control loops.

  • Structured Text (ST)
    High-level, code-like language suited for complex calculations, data handling, and advanced sequences. Great for modular, reusable logic.

  • Sequential Function Charts (SFC)
    Used for step-by-step sequences (startups, shutdowns, batch operations), with clear state transitions and interlocks.

  • Instruction List (IL)
    Supported for legacy systems where existing IL programs must be maintained or migrated, even though it’s largely replaced by ST in modern platforms.

Most projects end up using a hybrid: ladder for discrete logic, FBD for analog/process control, and ST/SFC for complex sequences and data handling.

Our Approach

  • Process-first – We start with how the plant, station, or system should behave under normal, abnormal, and failure conditions.

  • Standards-based – Logic is structured around IEC 61131-3 languages and internal coding standards for consistency and reuse.

  • Maintainable – Clear tag naming, modular design, comments, and version control so others can safely modify the system later.

  • Tested – Simulation, FAT/SAT, and commissioning checklists to verify real-world performance.

PLC & RTU Families We Work With

CueBid Automation is vendor-neutral. We program across a wide range of PLC and RTU platforms commonly used in municipal, industrial, and infrastructure applications.

PLC / PAC Platforms

  • Rockwell Automation / Allen-Bradley
    ControlLogix, CompactLogix, Micro800 family, legacy SLC and PLC-5 migrations, GuardLogix safety controllers.

  • Siemens
    SIMATIC S7-1200, S7-1500, and legacy S7-300/400; WinCC / TIA Portal integration where required.

  • Schneider Electric (Modicon)
    M340, M580, Quantum, and related Modicon families used in water, wastewater, and industrial applications.

  • Omron
    NJ/NX series, CP series, and associated IO and motion platforms.

  • Mitsubishi Electric
    FX, L, Q, and newer iQ platforms.

  • Other IEC 61131-3 Controllers
    WAGO, Beckhoff, and similar open-architecture PLCs commonly used in infrastructure and OEM skids.

RTU & Remote Controllers

  • Utility-grade RTUs used in water, wastewater, and power:

    • RTU and remote controller families commonly deployed in pump stations, lift stations, and tank sites

    • Rugged controllers with low power consumption and wide temperature ranges

  • Automation-class RTUs / edge controllers

    • Compact controllers combining PLC logic with native telemetry (cellular, radio, serial, Ethernet)

    • Edge devices used for remote monitoring, control, and local data buffering

If you already have a standard platform, we work within that ecosystem. If you’re starting fresh, we can help evaluate options with an eye toward lifecycle cost, local support, and integration.

Why CueBid Automation for PLC & RTU Programming?

  • Process-aware – We focus on how the plant or system behaves, not just “making the code compile.”

  • Vendor-neutral – We support the platforms you already own and help you choose wisely when you upgrade.

  • Maintainable logic – Clear structure, comments, and standards so operators and technicians aren’t trapped by opaque code.

  • Full lifecycle support – From initial architecture through programming, commissioning, optimization, and future expansions.