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3
General description
3.1 Transmitter/receiver
interface
3.2 Transmission method
12
Demag DRC radio control systems are designed for wireless control of hoist units
and cranes. They are the interface for manually controlled crane installations. The
applicable EC directives and standards are complied with for this application.
Demag DRC radio control systems consist of a radio transmitter/operating unit and
a radio receiver with interface to the crane control system.
DRC-10 hand-held transmitters in applications in connection with DRC-DR or
DRC-MP radio receivers are the subject of these operating instructions.
Radio receiver
DRC-DR
Hand-held transmitter
DRC-10
• The Demag DRC-DR radio receiver is a pluggable PCB for installation in the
electrical equipment cover of the DR hoist unit. The interface of this receiver
component to the crane control system and power supply by the DR electrical
equipment is the CAN safety bus. The DRC-DR radio receiver is exclusively
suitable for operation with a DR hoist unit.
• The Demag DRC-MP radio receiver is a complete unit with its own enclosure
and power supply from the control voltage network of the crane installation.
Relay contacts for the individual control commands and the emergency stop
circuit form the interface of this unit to the crane control system. An additional
semiconductor output with pulse width modulation is provided for infinitely vari-
able crane drives. The DRC-MP radio receiver is suitable for a wide range of
applications.
Demag radio receivers are provided for duplex operation and transmit information
to the DRC-10 hand-held transmitter. This increases safety of the radio system.
Status information of the crane control system and the receiver are shown in the
display of the DRC-10 hand-held transmitter.
The so-called ISM band (433 MHz) is used for transmitting the radio signals
between transmitter and receiver. Witin the ISM band 30 frequencies are used
alternately in a defined sequence (so-called frequency hopping). A random-check
generator detemines the sequence of the frequencies when radio transmission is
started. In order to increase transmission reliability, the information is transmitted
several times. This method in connection with frequency hopping provides for a
very high immunity to interference.
Frequency hopping is used for the first time with Demag DRC radio control system
types D1-FH and D2. In the case of the D1 type, the frequency of the radio signal
is not changed during a transmission cycle.
A decisive advantage of the frequency hopping transmission is that existing in-
formation contents are transmitted on several physical channels. This redundant
radio transmission 1) provides for an exceptionally high insensitivity of radio trans-
mission against other transmitters or electromagnetic interference.
1) Certain information contents are transmitted on up to 5 different frequencies. Only if (theoretically)
all frequencies used were occupied or disturbed by other radio systems, communication would be
interrupted.
Radio receiver
DRC-MP
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