Hardware-in-the-loop workflow

The payoff of everything in this section: run your real PLC program, on real hardware or a soft PLC, and watch it drive the virtual machine. Sequence bugs, wrong directions, off-by-a-revolution cam phasing: all visible on screen, before the machine exists or without occupying it.

The setup

1. Build the twin in Simulation mode first. Model the machine, dress the mechanisms, verify motion with simulated masters. This is your reference for "what correct looks like."
2. Map the PLC-owned variables. Axis actual positions and key status bits, via From Connection. Everything derived stays computed in the twin.
3. Switch to Online. The PLC program now animates the machine.

What you can validate

• Sequence logic, steps fire in order, interlocks hold, nothing moves before its guard condition.
• Motion coordination, cam phasing and synchronization windows: if the twin's flying shear cuts mid-product, so will the machine's.
• Directions and offsets, wrong sign conventions and home offsets are embarrassing on site and free to find on screen.
• HMI/operator flow, walk an operator through the virtual machine's behaviour before FAT.

What a twin does not validate

Machinery Twin visualizes what the PLC reports, it does not simulate physics back to the controller. Axis loads, collision forces, cycle-time-under-load and drive tuning still need the machine (or a physics-grade HIL rig). The twin's sweet spot is logic and kinematic commissioning, which is most of the schedule risk anyway.

Practical tips

• Run PLC and twin against a soft PLC on the same laptop (PLCSIM or a local TwinCAT runtime) for a fully portable commissioning rig.
• Keep a state machine animating product flow in the twin, driven by the PLC's tracking flags, products appearing and disappearing on cue is the fastest way to see tracking bugs.
• Save the project once mapping is complete; the same file remains your monitoring dashboard after commissioning.