Trace & Oscilloscope

The trace and oscilloscope tools let you capture, visualize, and analyze PLC variable values over time. Use them to verify timing, diagnose intermittent faults, and understand how signals interact during simulation.

Adding Variables to Trace

Open the Trace panel from the bottom toolbar. To add variables:

1. Click Add Variable in the trace panel header.
2. Browse or search the variable tree for the signal you want to monitor.
3. Select the variable and choose a display color.
4. Repeat for additional signals — you can trace up to 16 variables simultaneously.

Each traced variable appears as a labeled row. BOOL signals display as digital waveforms, while INT, REAL, and DINT values appear as analog curves.

You can remove a variable by right-clicking its label and selecting Remove from Trace.

Oscilloscope View

The oscilloscope provides a time-domain graph of all traced signals. The horizontal axis represents time and the vertical axis shows signal values.

Key controls:

• Time Scale — Adjust the visible time window from 100 ms to 60 seconds using the horizontal zoom slider.
• Amplitude Scale — Each channel has its own vertical scale. Right-click a channel label to set custom min/max values.
• Trigger — Set a trigger condition on any BOOL variable to start capture on a rising or falling edge. This is useful for capturing events that happen unpredictably.
• Cursors — Click on the waveform to place measurement cursors. Two cursors display the time delta and value difference between them.

The oscilloscope scrolls in real-time during simulation. Click Freeze to pause the display without stopping the simulation itself.

High-Frequency Capture

By default, the trace records values once per PLC scan cycle. For faster capture:

1. Open Trace Settings from the gear icon.
2. Set the Sample Rate to a higher frequency (up to 10 kHz).
3. Enable Oversampling to interpolate between scan cycles.

High-frequency capture increases memory usage. The trace buffer holds approximately 60 seconds of data at 10 kHz across 8 channels. Older data is discarded on a rolling basis unless you export it.

Analyzing Timing Relationships

The oscilloscope is especially useful for verifying that signals change in the correct sequence:

• Place cursors on two edges to measure the exact delay between an input event and the corresponding output response.
• Use the trigger feature to capture a specific moment repeatedly and compare waveforms across multiple runs.
• Overlay multiple BOOL signals to confirm that interlocks activate before actuators engage.

If you notice unexpected delays, check your PLC cycle time configuration — a longer cycle time directly increases the worst-case response time.

Exporting Trace Data

To save trace data for offline analysis:

1. Click Export in the trace panel toolbar.
2. Choose a format:
   • CSV — Timestamped rows with one column per variable, compatible with Excel or Python scripts.
   • JSON — Structured format with metadata including variable names, data types, and sample rate.
3. Select the time range to export (full buffer or between cursors).
4. Click Download.

Exported files include the project name and timestamp in the filename for easy identification. You can reimport CSV files into the trace panel to compare previous recordings against a live simulation.