Inkscape is very useful SVG image editor that can help us to create a device image of any kinds. The image can be used for building  SCADA or HMI. You can follow the video tutorial to know details about Inkscape.

How to draw a valve for automation system


=> Draw a rectangle, select it

=> Edit path by node (F2)

=> Path | Object to Path, drag a corner and make a shape like valve

=> Object | Group

=>Make the shape that fits to the screen (File | Document Properties | Custom Size |  Resize page to drawing or selection) 

=> Done