Chart recorders monitor and log information about a process. Typically this will be temperature, pressure or RH etc; but any parameter that can be converted to a suitable electrical signal can be recorded.
The data is recorded on a moving strip-chart or circular chart with colored pens to give a graphical view of the data over time.
Limited annotation of the data may also be possible, such a adding time/date or scaling information. Chart recorders do not always have a real time clock.