I’ve designed and commissioned mid‑scale conveyor systems for automotive tier suppliers, food packaging lines, and electronics assembly plants. One of the most common questions I hear from engineers and plant managers is: Which control platform should we standardize on — Rockwell, Siemens, or Beckhoff? The short answer is: it depends. The longer answer — which follows — walks through the practical tradeoffs I use when advising clients. I’ll share what matters in the field, the pitfalls I’ve seen, and specific scenarios where one platform tends to win over the others.

What I mean by “mid‑scale conveyor automation”

For this article, I define mid‑scale conveyors as systems that are larger than a single machine cell but smaller than full‑plant logistics: multiple conveyor lines, accumulation, sortation, indexing stations, basic indexing or servo sections, a handful of high‑speed transfer points, and interactions with PLC‑level I/O and MES. Typical channel counts range from a few hundred to low thousands of I/O points, several servo axes, and soft real‑time coordination requirements.

Primary decision criteria I use on projects

When I evaluate platforms I focus on criteria that matter for delivering predictable ROI on the shop floor:

  • Engineering skillset and vendor ecosystem — who can commission and support the setup quickly?
  • Deterministic motion and communication — does the platform meet your timing needs (e.g., coordinated servo, high‑speed I/O)?
  • Scalability & future integrations — will it handle expansions, MES/ERP and cloud data needs?
  • Total cost of ownership (TCO) — hardware, software licensing, engineering time, spare parts and lifecycle risks.
  • Openness and standards — network protocols (EtherCAT, PROFINET, EtherNet/IP), OPC UA support, and third‑party device interoperability.
  • Functional fit for conveyor features — built‑in supports for accumulation control, zone management, and line sequencing.

    • Rockwell Automation — when it’s the right choice

    Rockwell (ControlLogix/Studio 5000, CompactLogix) is often the safe default in North America. I recommend Rockwell when:

  • Your operations are already standardized on Allen‑Bradley hardware and you have local integrators certified in Studio 5000.
  • You require tight support from a local vendor network and prefer a single‑vendor stack for PLC, safety, and HMI.
  • Your conveyor needs integrate tightly with Rockwell‑centric MES or material handling packages that use EtherNet/IP.

    • Strengths I’ve observed:

  • Excellent local support and large installed base of electricians and integrators in the Americas.
  • Studio 5000 provides a familiar engineering environment for ladder and structured text programmers.
  • High reliability in standard PLC tasks and solid safety and motion options with integrated safety controllers.

    • Limitations to watch for:

  • Higher licensing and module costs relative to some competitors, especially for small runtimes.
  • Less native support for EtherCAT; Rockwell favors EtherNet/IP which is great for Allen‑Bradley ecosystems but can complicate integrating third‑party drives/providers that prefer EtherCAT.
  • Proprietary tendencies — integrating open software or non‑Rockwell motion libraries can increase engineering effort.

    • Siemens — when it’s the right choice

    Siemens (S7 / TIA Portal, SINAMICS drives) is a strong contender especially for European sites and projects that need robust networking and industrial standards. I pick Siemens when:

  • The plant uses other Siemens systems (motors, drives, SCADA) or is in Europe/APAC where Siemens support density is high.
  • Complex machine‑level sequencing and modular automation patterns are required across multiple lines.
  • There’s strong use of PROFINET/PROFIBUS and a desire to rely on established industrial communication standards.

    • Strengths I’ve observed:

  • Very mature hardware and diagnostics for large distributed I/O sets; excellent tooling in TIA Portal for device mapping and diagnostics.
  • Good motion control ecosystem (SIMOTION/SINAMICS) for synchronized conveyors and transfer systems.
  • Strong support for electronic nameplate and device replacement strategies that reduce downtime during rollovers.

    • Limitations to watch for:

  • Softer coverage of EtherCAT in older Siemens stacks (though Siemens has improved flexibility with recent offerings).
  • Engineering learning curve if your staff is not experienced with TIA Portal and Siemens naming conventions.
  • Cost of spare modules and the typical enterprise licensing model that can feel heavy for smaller integrators.

    • Beckhoff — when it’s the right choice

    Beckhoff champions PC‑based control and EtherCAT. I recommend Beckhoff when:

  • High‑speed, highly coordinated motion (e.g., multi‑axis transfer systems, linear motor conveyors, or web handling) is a requirement.
  • You want a modular, open architecture with a small hardware footprint and the ability to run deterministic control on standard PC hardware.
  • Openness (IEC 61131‑3 via TwinCAT, OPC UA, MQTT) and custom software integration (vision, AI inference at the edge) are important.

    • Strengths I’ve observed:

  • EtherCAT provides excellent determinism and low latency — ideal for tightly synchronized zones and servo networks.
  • TwinCAT supports multiple paradigms (structured text, real‑time C#, MATLAB/Simulink workflows) which is great for advanced control engineers.
  • Lower hardware entry cost and strong third‑party device interoperability via open protocols.

    • Limitations to watch for:

  • Smaller pool of field technicians comfortable with PC‑based control compared with PLCs in some regions.
  • Reliance on commercial PC hardware demands attention to industrial PC selection and lifecycle — bad PC choices can cause field headaches.
  • Less straightforward for teams that prefer ladder logic or a traditional PLC mindset.

    • Quick feature comparison

    Criteria Rockwell Siemens Beckhoff
    Best regions North America Europe, APAC Global (niche motion/PC‑control)
    Primary protocol EtherNet/IP PROFINET/PROFIBUS EtherCAT
    Motion determinism Good Very Good Excellent
    Openness Moderate Moderate High
    Typical TCO Higher upfront Medium‑high Competitive

    Questions I always ask clients

    Before choosing a platform, I run through a short checklist to avoid surprises on the shop floor:

  • What is the existing automation standard across the plant or group? Sticking with that reduces spare inventory and training needs.
  • Do you need sub‑millisecond coordination between axes or can you tolerate typical PLC scan‑based synchronization?
  • Who will maintain the system? In‑house electrical technicians, local integrator, or OEM service contract?
  • What higher‑level integrations are required (MES, WMS, ERP, cloud telemetry)? Which protocols do those systems support?
  • What is the expected lifecycle and expansion plan over 3–7 years?

    • Practical recommendations by scenario

    If you need quick guidance, here are my pragmatic recommendations from real projects:

  • Standardize on Rockwell if you operate in North America, have many Allen‑Bradley systems already, and want predictable local support.
  • Choose Siemens when you are in Europe/APAC, need enterprise‑grade device management and PROFINET fits your ecosystem.
  • Go Beckhoff when servo coordination, EtherCAT, openness for custom software, or cost‑effective distributed IO are top priorities.

    • Finally, remember that hybrid architectures are common: Rockwell PLCs for machine safety and line orchestration, Beckhoff motion controllers for a high‑speed transfer module, and Siemens drives for heavy DC motors. I’ve architected systems where each vendor’s strengths were used where they mattered most — but the integration cost must be accounted for.

    If you’d like, I can help you map these options to your specific conveyor layout, I/O count, and long‑term roadmap — share a PLC‑level I/O list or a single‑line diagram and I’ll sketch a recommended architecture and high‑level cost drivers.