uPlotDisplay Block

Real-time high-performance signal plotting with viewport pull from simulation buffer

# uPlot Display Block

Description

Real-time signal plotting block with configurable update frequency and rendering modes. Displays signals directly in the block diagram for interactive visualization.

Inputs

• Signal (number, multiple): Input signal(s) to plot. Can accept multiple inputs which are accumulated in a buffer.

Outputs

None - this is a sink block.

Mathematical Model

\text{N/A}

Parameters

Visual Configuration

• Title (text): Display title for the plot
• Line width (number): Thickness of the signal lines [1-4, default: 2.5]
• Show grid (boolean): Display grid lines [default: true]
• Show legend (boolean): Display signal legend [default: false]
• Show points (boolean): Draw points on each sample [default: false]
• Show statistics (boolean): Display min, max, and mean values [default: false]

Rendering Configuration

• Time window (select):
  • Rolling window (live tail): Shows the most recent data within the window duration.
  • Expanding window (grow until limit): Shows data from start, growing until limit.
  • Full span (start → stop): Shows the entire simulation record.

• Window duration (seconds): Duration of the rolling window. Only visible when Time window is set to Rolling. [0.5 - 3600 s]

• Update mode (select):
  • After simulation only: Data is buffered but not rendered during simulation.
  • Time-based: Updates rendered at specified frequency (Hz). Balances visibility with performance.
  • Live: Updates rendered every simulation step. May impact performance.
  • XY plot: First signal acts as X-axis, subsequent signals act as Y-axis.

• Refresh rate (Hz): Controls refresh rate for time-based rendering. Only visible in Time-based mode. [0.5 - 60 Hz]

Advanced Options

• Max display points: Limit the number of points drawn to prevent performance drops [default: 500000].
• Auto-scale Y-axis: Automatically adjust the Y-axis to fit all visible data. If disabled, uses Y-axis minimum and Y-axis maximum.
• Trigger: Stabilize periodic waves by aligning the window to a level crossing (only available in Time-domain rolling window).
  • Trigger source: Which input signal triggers (0 = first).
  • Trigger level: Amplitude threshold for the trigger crossing.
  • Trigger edge: Detect crossings on the rising or falling edge.
• XY: X/Y signal index: In XY mode, defines which signal indices represent the X and Y axes.

title

Type: text (Default: "Signal Plot")

Title parameter description placeholder.

viewportMode

Type: select (Default: "expanding")

Time window parameter description placeholder.

windowDuration

Type: number (Default: 10)

Window duration (s) parameter description placeholder.

renderMode

Type: select (Default: "timebased")

Update mode parameter description placeholder.

updateFrequencyHz

Type: number (Default: 10)

Refresh rate (Hz) parameter description placeholder.

maxPoints

Type: number (Default: 500000)

Max display points parameter description placeholder.

useAutoY

Type: boolean (Default: true)

Auto-scale Y-axis parameter description placeholder.

yMin

Type: number (Default: -1)

Y-axis minimum parameter description placeholder.

yMax

Type: number (Default: 1)

Y-axis maximum parameter description placeholder.

lineWidth

Type: number (Default: 2.5)

Line width parameter description placeholder.

showGrid

Type: boolean (Default: true)

Show grid parameter description placeholder.

showLegend

Type: boolean (Default: false)

Show legend parameter description placeholder.

showPoints

Type: boolean (Default: false)

Show points parameter description placeholder.

showStatistics

Type: boolean (Default: false)

Show statistics parameter description placeholder.

triggerEnabled

Type: boolean (Default: false)

Trigger parameter description placeholder.

triggerSource

Type: number (Default: 0)

Trigger source (signal index) parameter description placeholder.

triggerLevel

Type: number (Default: 0)

Trigger level parameter description placeholder.

triggerEdge

Type: select (Default: "rising")

Trigger edge parameter description placeholder.

xyXChannel

Type: number (Default: 0)

XY: X signal index parameter description placeholder.

xyYChannel

Type: number (Default: 1)

XY: Y signal index parameter description placeholder.

Behavior

1. Data Accumulation: Signal values are continuously accumulated in an internal buffer. 2. Rendering: Based on selected render mode:

• After simulation only: Buffer only, no visual updates during simulation
  • Time-based: Visual updates occur at the specified frequency (Hz), independent of simulation step size
  • Live: Visual updates every simulation step

Performance Considerations

• Update mode = After simulation only: Best performance. Use for long-running simulations.
• Update mode = Time-based (5-10 Hz): Recommended for most use cases. Good balance.
• Update mode = Live: Suitable for short simulations or high-performance machines. May slow down complex diagrams.

Buffer trimming: The viewport dynamically downsamples points if there are too many, using Max display points.

Tip: For large diagrams with multiple plots, use lower update frequencies (2-5 Hz) to maintain responsiveness.

Examples

Basic Signal Visualization

Step Block → uPlot Display
(Shows step response in real-time)

Transfer Function Response

SignalGenerator → TransferFunction → uPlot Display
(Visualizes system response)

Multi-Signal Comparison

Constant₁ ─┐
           ├→ Sum → uPlot Display
Constant₂ ─┘
(Multiple inputs accumulated in buffer)

Technical Details

• Update Frequency: Time-based, not step-based (independent of sample time)
• Color Mapping: Consistent with Analysis Panel via connection ID
• Data Format: Time series {times[], points[]} in internal state
• Rendering: Uses uPlot library for high-performance visualization

Remarks

• Live mode: Best for short simulations; use Time-based (5–10 Hz) for longer runs to maintain UI responsiveness
• XY mode: First connected signal becomes X-axis; subsequent signals are Y-axis traces
• Max display points: Prevents memory issues — when the buffer exceeds this, older points are downsampled
• Trigger: Stabilises rolling waveforms by aligning the window to a level crossing (rising or falling edge)
• After simulation only: Zero rendering overhead during simulation; data is fully available once the run completes

See Also

• Analysis Panel - Post-simulation signal analysis
• SignalGenerator - Generate test signals
• TransferFunction - System dynamics