Four common types of chart recorders are vertical, circular, flatbed, and digital. Each is an electrical or electromechanical device that uses pens to create graphs of sensor output signals over time.

• Vertical Chart Recorders – Vertical chart recorders, also called strip chart recorders, consist of a roll of paper that passes under one or more pens. The recorder is oriented vertically, creating a graph from the bottom to the top of the paper.
• Flatbed Chart Recorders – Flatbed chart recorders are horizontal recorders that operate in a manner similar to a vertical chart recorder to create graphs of the sensor output. They typically have fewer than five channels.
• Circular Chart Recorders – Circular chart recorders use a single sheet of paper that passes under one or more electromechanical pens. The pens produce a circular graph of the input signal. Each revolution occurs over a specified amount of time.
• Digital Chart Recorders – Digital chart recorders, also called paperless chart recorders, are the latest advances in the recorder industry. Instead of using electromechanical pens to create a graph of the input on paper, digital chart recorders create graphs on a digital display screen