Autonnic’s new sensors for engine lever controls

Autonnic, world leaders in fluxgate technology, is launching the first of a new range of waterproof, non-contact interaction devices - the A3300 Lever Control module.

A major requirement of the marine world is that conducting, corrosive seawater must not encounter electronic circuits. Yet controls, switches and buttons must be placed where a wet mariner can reach and touch them.

Having developed and patented some unusual aspects of fluxgates, Autonnic has applied the latest version of its 3-axis fluxgate technology to the solution of this interface problem. Autonnic’s solution is magnetic and therefore non-contact which solves the problem of how to keep the sea out of the electronics behind knobs, levers and buttons.

First of the series to launch is the A3300 set of OEM modules to provide the basis of non-contact engine lever controls for either one or two engines.

Originally based on cables, lever controls are the electrical means to communicate between the bridge and engine room. Fundamental to the operation is a method to convert a hand movement into an electrical signal. While a potentiometer is often used it has a number of disadvantages and Autonnic’s challenge has been to solve these while remaining cost-effective.

Firstly, potentiometers are not non-contact. The electrical part is mechanically connected and a rotary seal is therefore needed to keep the water out.

Secondly, potentiometers use sliding parts which wear and give rise to electrical noise which could lead to unreliable operation.

And thirdly, the potentiometer is itself a mechanical turning part and its own movement has to be rigidly accommodated within the final lever product design.

Autonnic’s solution is, naturally, based in its inherently low-cost magnetic technology. At its simplest we apply a magnet on a lever externally and a sealed internal fluxgate will indicate to what angle the lever has been turned. But for adjacent controls, such as a twin engine lever control, something else has to be put in place; Autonnic’s Switched Magnet Technology. (STM)

By using asymmetric passive cores on the lever shafts a common fluxgate can be shared between the two keeping all the advantages. Because SMT is a Vector Magnetic method it means that the background field is always being removed from the reading leaving it unaffected by stray magnetic fields.

And finally for the highest precision applications - higher even than lever controls - Autonnic can replace the passive cores with excited symmetric cores so that the movement of one shaft does not distort the field due to the other in even the slightest way so that cross-talk is completely eliminated.

About Autonnic

Autonnic Research Ltd is a world market leader in the design and manufacture of fluxgates for navigation systems to the marine and robotic markets. This reputation has been built on its continuous worldwide supply of fluxgate sensors and its unrivalled understanding of the technology, a highly experienced workforce and a commitment to quality, reliability and engineering support for marine autopilot and robotic guidance systems.

Autonnic create modules based on its magnetometer components by adding software and hardware to produce compass modules, wind speed and direction units, inclinometers and 2 axis sensors for archeology and sonar buoys. Autonnic has developed these new application modules under the name of Fluxgate World. Fluxgate World modules build on the in-house expertise of the basic fluxgate components by adding electronics, software, design integration and industrial design and has resulted in a range of products available for incorporation into a wide variety of sensing and measurement applications.

Autonnic continues to patent fluxgate devices and variants to lead to new, reliable and robust sensor and measurement components and modules.