Rs-485/Modbus Module - Libelium Waspmote Technical Manual

21.2. RS-485/Modbus module

Technical details:
Protocols: RS-485 and Modbus
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Standard: EIA RS-485
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Physical media: Twisted pair
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Connector: DB9
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Network topology: Point-to-point, Multi-dropped, Multi-point
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Maximum devices: 32 drivers or receivers
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Mode of operation: Differential signaling
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Maximum speed: 460800 bps
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Voltage levels: -7 V to +12 V
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Mark(1): Positive Voltages (B-A > +200 mV)
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Space(0): Negative voltages (B-A < -200 mV)
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Available signals: Tx+/Rx+, Tx-/Rx-(Half Duplex)Tx+, Tx-, Rx+, Rx- (Full Duplex)
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Available sockets in Waspmote: socket 0
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Applications:
Industrial Equipment
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Machine to Machine (M2M) communications
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Industrial Control Systems, including the most common versions of Modbus and Profibus
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Programmable logic controllers
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RS485 is also used in building automation
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Interconnect security control panels and devices
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Related API libraries:
Wasp485.h, Wasp485.cpp
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ModbusMaster.h, ModbusMaster.cpp
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ModbusSlave.h, ModbusSlave.cpp
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All information about their programming and operation can be found in the
the Modbus Communication
All the documentation is located in the
Guide.
Development section
RS-485 Communication Guide and
in the Libelium website.
-112-
Industrial Protocols
Figure: RS-485/Modbus module
v8.2