Labview Charts & Graphs

LabVIEW Charts & Graphs Creating a Graph: • To create a Waveform Graph, pop-up on the Front Panel > Controls > Graph >

Types of Charts & Graphs • Waveform Chart: special numeric indicator that can display a history of values acquired at a constant rate.

• Waveform Graph: special numeric indicator that displays an array of data. Updates after all points have been collected. • XY Graph: Displays data acquired at a non-constant rate, such as two columns or arrays data. • Digital Waveform Graph: Displays data as pulses or groups of digital lines. • (Windows) 3D Graphs: Displays 3D data on a 3D plot

Types of Charts & Graphs XY Graph Waveform Graph Waveform Chart

3D Graph Digital Waveform Graph

Waveform Charts

Accumulates after new run

Waveform Charts

Waveform Charts

Waveform Charts • Chart Update Modes The waveform charts use various modes to display data. These modes include Strip Chart, Scope Chart, and Sweep Chart.

Waveform Charts

Waveform Graphs

Waveform Graphs

Waveform Graphs Build a sine waveform

Waveform XY Graphs

Also you can use merge to plot two signals of xy in one graph by merging the x’s together and y’s together and enter both to xy graph

Waveform XY Graphs

Waveform & XY Graphs

XY Graphs & Planes • There are many planes in the xy graph. Such planes like Nyquist, S plane, Z plane and Nichols

XY Graphs & Planes

Digital Waveform Graph

Digital Waveform Graph

3D Graph 3D parametric graph:

creates a 3D graph control to draw a complex surface in 3D space. The control is wired to a subvi that takes in the data representing the surface.

3D Graph 3D surface graph:

creates a 3D graph control to draw a surface in 3D space. The control is wired to a subvi that takes in the data representing the surface

3D Graph • 3D curve graph:

creates a 3D graph control to draw a line in 3D space. The control is wired to a subvi that takes in the data representing the line

Other chart/graph types available Polar plot indicator

Smith plot indicator

Min-Max plot indicator

Distribution plot indicator

Radar plot indicator

Picture

Data types:

Charts & Graphs Features • Plot Legend: Defines the color and style of the plot(s). Resize the legend to display multiple plots. • Scale Legend: Defines labels for scales and configures scale properties. • X Scale and Y Scale: Formats the x- and y-scales. • Cursor Legend (graph only): Displays a marker at a defined point coordinate. You can display multiple cursors on a graph. • Scrollbar (chart only): Scrolls through the data in the chart. Use the scroll bar to view data that the buffer does not currently display.

Example

Assignment 1- Sketch the function x3+2x2+3cos(x) given the inputs: (use For Loop structure) – the value of xmin – the value of xmax – the step value 2- Figure below shows a simple level control system in which a closed or opens the valve by a relay. Input flow is not controlled. The relay opens the valve if output voltage greater or equal 6.0 V and closed below that. The level sensor has a transfer function of Vh=0.8h+0.4 V • •

find the value of amplifier gain, K, required to open the valve when the level reached 2m show two LEDs indicators that tell if the valve is opened or closed

Assignment

3) The tank shown below has the following Boolean variables: flow rates QA, QB and QC; Pressure P; Level L All are high if the variable is high (true) and low (false) otherwise Design a labview VI to give two alarms (LEDs) as follow: OV (overfill) alarm when: • if either input flow rate is high while the output flow rate QC is low, the pressure is low and the level is high. • If both flow rates are high while the output flow rate is low and pressure is low. EP (empty) alarm when: • if both input rates are low, the level is low and the output flow rate is high • if either input flow rate is low, the output flow rate is high an the pressure is high.

Assignment 4) • • • • •

The output voltage is as follows: Vout = Vin when -2 2 Vout = -2 V when Vin<-2 Using Labview, if Vin is sine wave, sketch 1. 2. 3. 4.

Vin vs time graph Vo vs. time graph Vin and Vo vs time graph Vo vs Vin graph