Device Description HG G-193x0-B | English, Revision 02 | Date: 07.05.2018
9
Introduction – Chapter 2
2.5 Functional Principle
Note
The functional principle below is explained using a guide wire installation. An energy track
installation has slightly different voltage curves but the basic principle is the same.
A frequency generator feeds a current into a guide wire installed in the ground. Along this
wire an alternating magnetic field is generated. The sensor measures the magnitude of the
induced voltage in two horizontal coils.
Figure 1
Principle of the guide wire track guidance
By evaluating the voltages induced in the two horizontal coils for each frequency a sum and
difference signal are calculated – U
sum
and U
diff
– and output via the bus. The difference
signal shows maxima at both sides of the wire (one positive and one negative) and crosses
zero directly above the wire. Thus it may be used to control the vehicle.
Figure 2
Voltage curves guide wire track guidance: Sum / difference signal and Detect
Frequency
Generator
Vehicle
Inductive Guidance Sensor
Guide Wire
Magnetic Field
Frame
‐300
‐200
‐100
0
100
200
300
400
‐150
‐100
‐50
0
50
100
150
U
sum
U
diff
Detect 0/1
(output via bus)
Usum, signal strength decides
when to set Detect to 1
Udiff, vehicle control
