SENSOR OPERATING IN FORESTRY LOGGING MACHINE

Modern forestry logging machines are complex and sophisticated pieces
of equipment able to fell and manoeuvre trees andtrunks efficiently. To
help control the hydraulic controls on the machines, sensors are fitted
inside the hydraulic cylinders. The sensors provide feedback
on the position of the rams to the main control system. The hydraulic
cylinders are a compact design and have very little room to house
the sensor and any associated electronics.
In this application it was necessary to design the sensor with a small
space envelope in the cylinder and to use an external electronic interface. The
Positek P106 inductive
position sensor was chosen for this application because of
its small size and the compact electronic interface. Usually the P106
sensor interface is mounted onto the body of the hydraulic ram. However,
in this particular application the main system control electronics
was mounted close to the cylinder. This meant that the Positek
interface could be installed directly into the main module.The Positek
interface is only 32mm diameter and is available as a double-sided
surface mount PCB assembly. With integral pins and a specially
moulded support ring it can be mounted directly onto the main control
circuit. This assembly is very easy to assembly and eliminates
the need for separate electronics enclosures and the associated wiring
and connectors.
In the logging industry much of the work is carried out in the winter
when temperatures can vary from -40° up to 40°C during the
working day. This is a harsh temperature cycling routine and
introduces special needs for the protection of electronics against
condensation forming during the thermal cycling.
The P106 sensor incorporates technology developed by Positek
and used in its other displacement sensor products. This PIPS®
technology is based on inductive coils and uses a unique custom integrated
circuit to produce an accurate analogue output signal.
For more information contact: Sales at Positek Limited
Tel: +44 (0)1242 820027 Fax: +44 ( 0)1242 820615