Device Description HG G-71915ZA | English, Revision 01 | Date: 09.09.2021
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Chapter 5 – Operating Principle
5
Operating Principle
The transponder antenna detects the position of moving parts by means of passive
transponders. Downstream navigation systems (e.g. vehicle PLC, Götting navigation
controller HG G-73650ZA), which process the data detected by the antennas, can be
used to control automated guided vehicles (AGVs) contact-free.
All important settings, calibrations and updates can be made via the USB interface.
Figure 6
Simplified principle of transponder positioning
In position detection with transponders, a transponder antenna detects a transpon
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der at the nominal reading distance and determines its position in the antenna field.
Typically, the transponders are mounted at fixed positions on the ground and the an
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tenna moves above them, e.g., by being attached to a vehicle moving over a course.
Alternatively, the antenna may be mounted at a fixed position and the plant part with
transponder moves relative to it, e.g., an arm of a robot or an electric monorail.
In the following, we refer to the application on automated guided vehicles (AGVs)
with transponders in or on the ground and the antenna installed on the vehicle.
5.1 Position Detection with Transponders
In position detection with transponders, the antenna permanently irradiates the area
under its reading side with its transmission frequency. The transponders are passive
and do not require an energy supply of their own. As soon as the antenna passes
over a transponder, it is inductively supplied with energy via the antenna's energy
field. It automatically wakes up and uses the received energy to send back its code
at half the transmission frequency of the antenna. Thus, only pairings of antennas
and transponders whose transmit and receive frequencies match are possible. Fur
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thermore, there are other systems for transmitting and decoding the code which are
not described in this device description.
Only one transponder at a time may be in the antenna's reading range. In addition to
the transponder code, the antenna emits a positioning pulse (PosiPulse) when it
moves over a transponder and the center axis of the antenna crosses the transpon
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der. This enables the detection of predefined positions.
Due to the low operating frequencies (128/64kHz), transponder detection is practi
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cally not affected by non-conductive materials (liquids, gases or even solids).
Transponder
antenna
Direction of travel
Transponder
Ground
Vehicle
