Basic knowledge - LED indicators

RHEINTACHO electrical indicator systems can be used to display process variables such as rotational speed, velocity, flow, filling levels and positions.

The indicators are exceptionally robust and ideally suited for use in harsh, industrial environments. We also take account of operational aspects, using clear displays with a well-structured, high-contrast and clear figures making them easy to read. Dials can be marked with features such as red lines, warning zones or direction of movement.

In addition to the analog dials, it is also possible to supply digital and LED indicators where this is preferred, as well as to include counters.

Operating principles

An electrical signal is generated at the point of movement and transmitted to the indicator which causes the pointer to move across the scale. This movement is determined by specification, and each instrument is calibrated to suit the required range and units of measurement.

The electrical signal can be generated in different ways:

  • Using a tacho generator which is connected to the point of movement and generates a current or voltage signal according to the speed of rotation
  • Using a non-contact sensor which measures the speed of a toothed wheel and generates a frequency signal according to the speed of rotation. The sensor typically requires a power input, and the signal will need to be converted to a current or voltage output
  • Using an existing electrical output/controller

A key attraction of this system is that the location of the indicator can be up to several hundred meters away from the point of measurement, for example on ships, where the speeds of the engines are displayed on the bridge.

The range is extensive, and whilst each instrument is always calibrated to specific requirements, there is a range of standard casing configurations and input standards.

Electrical indicators are regularly used on large engines where the display needs to be away from the point of measurement for safety and comfort reasons. Similar reasons dictate the use on trains, trams and other forms of transport. These indicators also benefit from being able to connect multiple units to a single source for displaying data in a range of locations.

Where required, there are further options such as illuminated displays, LED displays and counters.

Where there is a need for limiting functions for reasons such as safety, it is possible to use a relay switch alongside the indicator as part the control system.