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uwekaditz
fd96c7dcde
CHG: all functions and variables moved to P092_data_struct() CHG: keeping only global values needed for all tasks CHG: description in P092_DLbus.rst that each velue need a new device task
57 lines
1.9 KiB
ReStructuredText
57 lines
1.9 KiB
ReStructuredText
Introduction
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------------
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The DL-Bus is used in control units e.g. sold by `Technische Alternative <http://www.ta.co.at/>`_.
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The DL-Bus serves as a bus line for various external sensors and modules.
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The DL-Bus is a bidirectional data line and only compatible with products of Technische Alternative.
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The data transmission looks as follows:
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* In an infinite loop, a logging data frame is created by the control one after the others on the data line.
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* So that the beginning of a data frame can be detected, a SYNC of 16 high bits is sent before the first data byte.
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* The data transmission is carried out as Manchester code (EXOR linked) with a display clock of 50 or 488Hz (depending on control type).
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This is necessary to ensure the supply voltage of the logger and DL sensors from the data signal.
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If the receiver is synchronized to the display clock, the correct bit value appears always during the second half period of the data bit (inverted in the first half period).
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.. note:: A new device task must be created for each value to be read from the DL bus!
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Wiring
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------
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The DL-Bus consists of 2 wires:
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* DL
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* GND (sensor ground).
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The power supply for the DL-Bus sensors is supplied via the DL-Bus itself.
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Some DL-Bus devices can/must be powered via a 12V source, e.g. that of the CAN bus (this is explicitly noted in the operating manual of that sensor).
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The cable routing can be star-shaped or serial (from one device to the next).
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Any cable with a cross-section of 0.75 mm2 up to a maximum length of 30 m can be used as a data cable.
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Over 30 m, the use of shielded cables is recommended, which increases the permissible length of the cable to 100 m.
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Protocol
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--------
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Transmission of a data byte
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.. image:: P092_DL_bus_databyte.png
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Transmission of a data frame
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.. image:: P092_DL_bus_dataframe.png
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Data frame on the DL bus
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.. image:: P092_DL_bus_dataframelog.png
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Display clock
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.. image:: P092_DL_bus_displayclock.png
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