Chart Recorder Review

Electronics, Instrumentation & Electrical Database

Electronics Testing Chart Recorder Review

A Chart Recorder is an electromechanical piece of equipment that documents/records a mechanical or electrical input signal or trend onto a chart, paper, or a rolled piece of paper. In addition, chart recorders can record numerous inputs using a set of different color pens (chart pens) and can also record findings onto circular charts or strip charts. Applications for chart recorders include documenting pressure, humidity, temperature measurement, water, electrical, industrial and process parameters, to name a few. Chart recorders have become more complex and capable in recent years in fact, many current chart recorders can record data and download the information to a computer (a laptop or PC), as well as store and record data in a digital format.

Generally, there are five types of chart recorders:

Circular Chart Recorders this type of chart recorder records information in a circular format. The chart recorder paper is rotated under one or more chart pens, with the pens being deflected in ratio or proportion as the input signal varies, with the result being a circular chart. These types of chart recorders are useful for tracking batch processes - in other words, when the process time is known. The charts are intended to rotate to cover standardized time periods, such as hour, 24 hours (one day), 7 days, and so on.

Strip Chart Recorders are comprised of a strip or roll of paper that is passed in a linear fashion below one or more chart pens. When the input signal changes, the pens change or deflect accordingly, with the result being the chart output. Strip chart recorders are commonly used for the recording of processes that are continuous in nature, and are used in process measurement and for laboratory purposes.

XY Recorders as the name implies, XY recorders have two inputs and then creates a graph or chart of one input compared to the other. XY recorders are used to establish the relationship of the two observed inputs.

Paperless Recorders this type of chart recorder utilizes a graphic display (CRT or equivalent); no paper is charted. The information can be stored in the internal memory of the paperless chart recorder or to a memory card (with the intention of downloading the data to a PC or laptop computer). Rather than printing reams of paper, the information can be stored and documented in the computer memory.

Hybrid Recorders a hybrid chart recorder can be used as a data logger or as a chart recorder. As a standard chart recorder, the hybrid recorder can generate a log or chart of the various inputs. As a data logger, the hybrid recorder can generate a digital stamp of the data being monitored. Hybrid chart recorders are available in multichannel configurations or designs, with one print head or module handling the tracking of all channels. The advantage of a hybrid chart recorder is its economical cost in tracking multiple channels; the prime disadvantage of hybrid recorders is that their response time is not as fast as traditional pen-type chart recorders.

• Some questions that should be asked in selecting a Chart Recorder:
• What number of inputs are to be recorded?
• What kinds or types of inputs are to be recorded?
• Are alarms (depending on signal variation) needed? What kind?
• What kind of recording is needed? Continuous? Certain (preset) times?
• What kind of power is available for the recorder?
• Is there a computer communication output or interface required?