Guide
#Time and step mode
#Observable timing
The simulation slows telegram propagation so each event can be inspected. These values are model settings, not physical KNX bus timings. For comparison, on a twisted-pair line at 9600 bit/s, a switching telegram and its acknowledgement occupy the bus for about 20 ms.
| Event | Simulated delay |
|---|---|
| Object transmission onto the bus | 550 ms |
| Between adjacent devices on a line | 250 ms |
| Coupler input, decision, and output | 150 + 900 + 150 ms |
| Bus arrival at a receiving object | 500 ms |
| Default status feedback or motor start | 300 ms |
A lamp or motor changes only after the receiving object processes the telegram.
#Speed and pause
Speed controls multiply simulated time: slower, normal, faster, and ×5. The button long-press threshold (longPressMs, 0.5 s by default) uses real time. While paused, a button press is registered but its telegram waits for simulation time to resume. A hidden tab or slide pauses without later catching up.
#Simulated clock
A scenario can declare a simulated wall clock. Clock masters, time switches, and time windows use it:
"clock": { "start": "2026-09-28T21:57:00", "speed": 60 }startis the local date and time at the start of the simulation, without a time zone.speedis the number of clock seconds per simulated second (1 by default, at most 3600). With 60, one clock minute passes every simulated second.
The clock follows simulated time: it stops while the simulation is paused, and the speed controls apply to it as to everything else. With a clock, simulated time keeps running even when the bus is idle.
The diagram shows the date and time in a bar at the top left of the diagram area, above the drawing. Set time opens a field to move the clock to another date and time, for example just before a programmed switching point; devices then send the time again and reschedule their programs. From JavaScript, diagram.setClock("2026-10-01T06:59:30") does the same.
#Step mode
Step mode stops at explanatory events, including telegram transmission, a coupler's route/filter decision, an object's acceptance or rejection due to W, output changes, and timer expiry. Press Next to continue to the following event.
#Determinism
Time advances in whole milliseconds through an event queue. Advancing by 20 seconds in one call or in smaller steps gives the same final state for the same inputs.