Lanterns measured using JVL Controllers

 

One of the tasks of the photometric department of The Royal Danish Administration of Navigation and Hydrography (RDANH) is to measure the output of lenses and lanterns of navigation beacons and buoys. It is essential that these data are of the highest quality since they are employed in navigational safety for mariners. The information is published for example on sea charts.

The beacon lanterns are mounted on a Goniometer table, which can be rotated both horizontally and vertically. Light emission is measured using a lux meter at a distance of up to 57 metres in a long measurement corridor, and is measured as a function of the lantern's rotational angle in both planes. Until now these measurements were taken manually, but the RDANH wanted to automate the measurements to perform them faster and with greater accuracy.

In cooperation with JVL, the RDANH developed a solution based on a step motor control system supplied by JVL.
The Goniometer's movements are carried out by 2 Zebotronics step motors equipped with TR planetary gears that are controlled by a 1½-axis controller. This consists of a JVL SMC35B Step Motor Controller and a JVL Ministep Driver SMD41C3. The controller is controlled from a PC for which JVL has supplied software that facilitates easy entry of required movements in both planes. An autostep-function enables the table to be moved in steps a required number of degrees, e.g. from 0 to 90 degrees, with a suitable step interval for reading the lux meter.

The RDANH is continuing development of the system so that light and positioning measurements can be automatically plotted.

 

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