Table of Contents
WTNet
WTNet is an idea for controlling large scale outdoor railroading.
Principle
WTNet is based on the Walkie-Talkie technique with one master, Rocrail, using the CBUS protocol.
Features
- Reduce field wiring.
If the outdoor layout already uses DCC on the tracks this WTNet can be used for sensor reporting by the loco itself by RFID-Tags under the tracks; No need for detection sections or Reed contacts.
System Overview
LC-GCrf
This is the train controller with the following features:
- 200Hz duty-cycle Motor control.
- 8 function outputs.
- RFID reader connection.
- 22000µF power buffer.
The tracks are expected to deliver at least 16V and enough power.
CAN-GCrf
The CAN-GCrf is protocol compatible with the CAN-GC3 which make it possible to use the CANCAB too for controlling the locomotives.
CAN-GCLN
The CAN-GCLN makes it possible to use LocoNet throttles like FRED's.
CAN-GC1e
Rocrail connects to the CBUS by the CAN-GC1e ethernet TCP/IP interface.
andRoc
andRoc can be used as usual with its rich range of possibilities.
Equipment
Loco
- A RFID reader for scanning RFID-Tags.
- A tranceiver unit.
- A PIC based controller: GCrf.
Master
- A tranceiver unit.
- A PIC based controller:
- Communicates with the tranceiver over SPI.
- CAN interface. (CBUS)
The master supports the same CBUS opcodes as the CANCMD/CAN-GC3.
Sequence
- The master send subsequently commands to every known loco in the system.
- It will switch to receive mode and wait for a response from the addressed loco.
- This response may include sensor information like magnet or RFID-Tag.
- After the response is processed, or a timeout occurred, the next loco is send a command → goto 2.
The command packet include a loco address.
All locos are by default in receive mode and will only process commands matching its own address.
Links
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- mrf24j40-radiodriver.zip Source code
- 802.15.2-2003.pdf IEEE 802.15.2-2003