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Rangachari Anand

November 15 2005 2004

Introduction

Here is a preliminary report on my efforts in controlling my trains with Python. My setup is shown in the diagram below:


The components that I am using are:

• The Uhlenbrock Intellibox: This box sends both power and control signals to the the locomotives.
  
• srcpd running on a Linux server (an old installation of Redhat 9.0). Client communicate with srcpd using the SRCP (Simple Rail Control Protocol). srcpd communicates with the Intellibox over a serial cable.
  
• A modified version of the rcsh Python client software on a Windows XP laptop. Since the version  of rcsh that is available on this site is intended to work with an older version of the srcp protocol, I had to modify it to bring it up to date.

This is what a typical control script looks like:

---

Connect( '192.168.0.4')
L = loco( 61)
L.setF( 4, 1)
L.setF( 3, 0)
L.setF( 2, 0)
L.setF( 1, 0)

def From3To1():
   L.setDirection( 1)
   L.send()

   L.setSpeed( 50)
   L.send();

   while (srcp.getFB( 2) == 0):
      time.sleep( 0.5)

   L.setSpeed( 25)
   L.send();

   while (srcp.getFB( 1) == 0):
      time.sleep( 0.5)

   L.setSpeed( 0)
   L.send()

---

Here is how it works:

• I have a short linear stretch of track  on which there are three sensors (implemented with a Viessmann 5211 feedback  decoder).
  
• The script assumes that the train is standing at station 1.
• The train moves at speed 50 (127 max) until it reaches station 2
• The train slows down to speed 25 until it reaches station 3 where it comes to a stop.

Here is a video showing the script in action (Click on image to start the video):







 
Text Copyright © 2004 Rangachari Anand, all rights reserved