Most PLC tools only let you watch values. CODESYS goes further: set a breakpoint on a line and the controller halts there, mid-scan, so you can single-step the logic and inspect every variable — just like debugging software. Click in the gutter to drop a breakpoint, then step through this fill-control routine.
Click a line's gutter to set a breakpoint (red dot). Press ▶ Run to BP and execution halts there — the controller is genuinely paused on that line. Then ⏭ Step through, watching the variables on the right change as each statement runs. This is the debugger PLC programmers coming from software actually expect.
⚠️ Breakpoints halt the real controller — fine on a test bench, dangerous on live machinery (outputs freeze where they are). For running plant you use the non-intrusive Trace recorder instead: it samples chosen variables at the task rate and plots them like a scope, without ever stopping the scan.
👁️ Inline monitoring — live values appear right beside the code/variables while online. The everyday view.
🔴 Breakpoints & stepping — halt on a line, step into/over/out, inspect the call stack. Software-grade debugging — for the bench.
📈 Trace — sample variables at task rate and plot them; catch a glitch too fast for the eye, without stopping the controller.
✊ Write & force — prepare a value and write it once, or force it held; plus the device log for events and errors.
A line is in production and you must capture a fast intermittent glitch without stopping it. Which tool?