SC11 Chart Recorder

The chart recorder simulates plotting on a paper chart which is up to 200 divisions long, of which typically 10 divisions are displayed as it scrolls. Controls for vertical gain and chart speed are provided. Pan and zoom controls enable any section of the plot to be examined.

The chart recorder can be used to monitor slow events. The bandwidth of the SC11 AC field sensor may be extended down to 0.01 Hz to monitor the magnetic field of lifts and passing trains. True DC measurements may be made using the DC sensor with the Sensor Interface. A typical chart recorder display is shown above. It is very useful to be able to relate particular movements in the chart recording to real-world events and so it is now possible to place markers into the chart, as above, to state what and when an event was.

Sometimes an event that is being charted lasts longer than the scroll time across the screen, or occurs just as the screen is renewed. The time axis can be resized to allow for this but this can reduce the detail immediately visible in the trace. In this event there are alternative update modes that keep the previous page of the trace on display. The picture below shows the sweep chart mode.

An integrating filter tailored to the 731A accelerometer allows direct displacement and velocity charts to be made.

A narrow band filter allows the RMS or Pk-Pk value of the signal to be recorded at an adjustable centre frequency. Version 4.2 also allows the user to adjust the bandwith of the chart within the practical minimum and maximum of the system.

The data logging feature of the chart recorder writes each point to a file as the data is acquired. This can be used when the data collection period is longer than the 200 divisions of chart memory such as for open-ended long term recording of disturbances that occur occasionally or overnight. The figure here shows the comprehensive start and stop controls for data logging.