Sysmac Studio · NJ/NX · the laptop dress-rehearsal
Simulation & Digital Twin
Trace a filling sequence before opening an NJ/NX project. This independent JavaScript model lets you pause the conveyor and jam a valve while watching the signals. It illustrates a test method; it does not run Sysmac Studio, emulate an Omron CPU or connect to a controller.
Browser model · no PLC connection🏭 a virtual machine⏩ faster than real life
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01 · The living line
One machine, watched three ways at once
Start the model and follow one bottle from arrival through filling to departure. The lamps show model state, and the highlighted pseudocode explains its decisions. Use the jam control to compare the commanded valve state with the simulated liquid flow. Neither the counter nor the animation measures an NJ/NX task execution time.
👀 Watch the link: when BottleAtFill flips to TRUE, rung R2 lights, FillValve goes green, and only then does liquid pour. Machine, signals, and logic are never out of step — because they're all the same program. That is what "running in simulation" actually feels like.
02 · The cheap mistake
You just broke a machine and it cost nothing
Hit ⚡ Jam the valve above and watch what happens: LevelFull goes TRUE, R3 tries to shut the valve — but it's stuck open. The bottle overflows, the spill counter climbs, the line locks up. Now imagine that on the real plant floor: sticky syrup over a €90k machine, a stopped line, and a very bad afternoon. Here it's a number you reset with a button.
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Observe the failed close
While filling, jam the valve. A close command cannot stop the modelled flow. Write down the evidence available from the level signal and the evidence still missing without valve-position or flow feedback.
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Keep the model assumptions visible
The model simplifies sensing, transport and liquid flow. It does not simulate controller firmware, real I/O refresh or communication delays. A working animation is not a commissioned NJ/NX application.
read→solve→write
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Compare fault injection times
Inject the same jam before and after the full-level indication. Record the state where the fault becomes visible. The speed control helps inspection; it cannot establish a controller watchdog limit.
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Define recovery before reset
Before using Fix & mop up, identify which conditions must be restored. On a real installation, recovery also depends on the process, stored energy and the machine safety design; a browser reset has none of those effects.
no risk
03 · The real vocabulary
"Simulation" and "twin" aren't the same word
Use the buttons to compare test boundaries: software-only logic tests, physical-controller tests and models associated with real assets. Each answers different questions; adding hardware alone does not make a test complete.
Automatic model feedback is useful in software-in-the-loop testing, but it does not by itself establish a digital twin. Describe the real asset, operational data connection and validation assumptions before using that term.
04 · Check yourself
One that separates the two
Your virtual line filled a bottle, the photo-eye tripped on its own, and the valve opened — all with no clicking from you. Which setup were you running?
Prepare a Sysmac Studio simulation session
Sysmac Studio provides an integrated simulator for supported controller projects. Check the selected NJ/NX model, software version and supported instructions in the current operation manual. A browser lesson and an IDE simulator have different boundaries.
Work from a saved project copy. Record the controller model and Sysmac Studio version so another engineer can repeat the session.
Identify the task and programs containing the filling sequence. List the variables that substitute for BottleAtFill and LevelFull, and separate them from physical I/O mappings.
Start an offline simulation using the workflow documented for your version. Monitor the sequence state and output commands. Change one input at a time and record the expected transition.
Repeat with contradictory sensor states, a missing full-level indication and a restart. Check that the application defines a response rather than relying on the model to recover automatically.
Record exclusions: controller-specific functions, networks, drive behaviour and actual actuator feedback may require another test environment or hardware. Confirm each restriction in the manual.
The task-cycle model explains why an input change may be observed on a later update. Compare TwinCAT target selection for a different engineering workflow rather than assuming the same menu or runtime applies.
Record actual test results in your own project. TryPLC does not claim that this model certifies the application, its real-time performance or its safety functions.