Woodworking Machines

Embracing RMP, a PC-Based Master and Motion Controller

When these OEMs approached us, they were exploring alternatives to traditional PLC-based control for their next-generation machines. They ultimately chose our RMP EtherCAT Motion Controller – a PC-based soft motion controller – as the brain of their systems. RMP is a software motion controller that runs on a standard industrial PC instead of a dedicated PLC or proprietary hardware. It operates under a real-time operating system environment on the PC, delivering deterministic control just like dedicated motion hardware. We support two main configurations: Windows with an INtime RTOS kernel, or Linux with the PREEMPT_RT real-time patch​. In practice, this means the OEM can use a single PC to run both the machine logic and the graphical HMI, while RMP’s firmware runs on a reserved CPU core to guarantee real-time performance. In one case, an OEM preferred Windows so they could build a rich user interface for their machine using .NET, while still achieving sub-millisecond motion loop times via the INtime co-kernel. Another OEM opted for a Linux controller, leveraging PREEMPT_RT for real-time behavior and enjoying the stability and openness of a Linux system. RMP was flexible enough to support either OS platform without sacrificing deterministic control, as it simply dedicates a core to the real-time tasks and uses EtherCAT for all field communication.

As long as the IPC has a suitable NIC (network interface) for EtherCAT and a multicore CPU, RMP takes care of the rest: one core runs the RMP real-time engine, and the other cores handle the HMI, vision, or other applications, communicating through shared memory via our RapidCode API.

Advanced Motion Control Features in Action

Once the OEMs adopted RMP, they were able to leverage a host of advanced motion features that improved their machine performance:

• Coordinated Multi-Axis Motion: RMP natively supports coordinated interpolation across axes for contouring. In CNC woodworking routers, this meant the X, Y, and Z axes (and others when present) could move in perfect sync to follow complex tool paths. The motion planner in RMP handles linear and circular interpolation in 3D space, as well as spline or custom kinematic paths if needed. In fact, RMP even includes a G-code interpreter and robotic kinematics library for those who want to program at a higher level.
• Electronic Cam and Gear Functions: Many woodworking processes require synchronization between axes. Using RMP’s electronic gearing, one axis (or virtual master) drives others with a precise ratio or motion profile. For example, in dual-axis gantries, master-slave electronic gearing ensures motors move in perfect unison, preventing misalignment and improving overall precision.
• Position-Based Triggers and Fast I/O Response: In high-speed machinery, sometimes an action needs to occur at a precise position or event – for example, firing a pneumatic cylinder to push a cut piece off a conveyor exactly when it reaches a certain location. Because RMP runs the motion and I/O handling in the same real-time core, it can respond to an encoder position or sensor input immediately within the servo cycle. One panel saw OEM loved this – they set up a trigger so that as soon as the saw blade reached the end of a cut, the clamp release solenoids would energize within the same millisecond, improving throughput. For more complex conditional logic, we also provided our RTTasks real-time scripting, which a customer used to run a custom tension control loop in the background of the motion system.
• High-Speed Feedback and Adjustments: RMP’s fast servo update rate (typically 1 kHz, configurable up to 4–8 kHz in some cases) means the controller can read sensors and adjust outputs with very little delay. If an OEM wanted to implement a form of active control – for example, adjusting feed speed on the fly based on spindle load or vibration – the PC controller could handle it by reading an analog signal from a load sensor. This would alter the motion command in the next cycle.
• Simplified Homing and Calibration: Each axis on these machines needs a homing sequence at startup (to establish a reference position via a limit switch or sensor). RMP provided built-in homing modes (like moving until a switch is detected, or using an encoder index pulse) which we configured for each machine’s needs. The OEMs found this library of motion functions very convenient – rather than writing raw logic to handle homing, they called our API to perform it, drastically reducing initial programming time. The coordinated homing of multiple axes (for instance, homing both Y motors of a gantry simultaneously and squaring the gantry) was also supported, which got the machines up and running faster each day.

Conclusion

By adopting a PC-based, software-centric motion controller, our OEM customers gained unprecedented flexibility and performance:

• They harnessed high-performance multi-axis motion control (supporting far more axes and complex trajectories than they initially thought possible)​, which in turn allowed them to design innovative machine mechanics (like multi-head, multi-axis systems) with confidence that the control system can keep up.
• They simplified their designs by consolidating control tasks – motion, logic, I/O, safety, HMI, even vision – onto one platform, reducing hardware and points of failure.
• Through EtherCAT and open standards, they achieved interoperability and scalability. Whether it was adding a new axis with a drive from a different manufacturer, or expanding the I/O with a unique sensor module, RMP’s open EtherCAT master made it plug-and-play. And with Safety over EtherCAT, they maintained high safety levels without sacrificing flexibility or adding complexity​.
• The OEMs also benefited from the ease of development and maintenance. Their software teams could work in familiar programming environments (leveraging libraries and tools from the broader IT world), resulting in faster development cycles and more robust code. 
• Importantly, the future-proofing aspect cannot be overstated. With a PC-based controller, upgrading the computing power in the future is as simple as choosing a faster CPU or more memory.