CHART RECORDER

Typical Number in Hospital: 50

Cost Bands: 3,4

References: 3

A permanent record of measurements may be required if several variables are being monitored simultaneously or the rate of change is very rapid. A chart recorder saves the information as a graph written by a pen. The chart may show the variables on the Y-axis and time on the X-axis (Y-T recorder) or two variables may be plotted against each other (X-Y recorder) on a single sheet of graph paper (as opposed to a strip of paper).

The paper strip may be driven by a motor and gearbox over a roller, sometimes with a choice of speeds. The pen(s) usually move along the vertical axis and the two main types are potentiometric and galvanometric. The pens may write using ink, or using special paper responding to pressure or heat of the pen.

Chart recorders are used to provide permanent records of ECG waveforms, blood pressures, EEG, EMG, etc. Also they are used in the pathology laboratories to record colorimetric and spectrometric information during analysis of samples.

Chart recorders may be single channel, have up to twelve channels.