Electrial setup, rs485 protocols

Todays lecture will cover discussions about

1. setup and handling of the CrustCrawler form a communication point of view

Tutorials for RS485

• tutorial 1

• a small video

protocols

• Dynamixel protocol 1

  • org link

• Dynamixel protocol 2

  • org link

• CRC calculations

  • org link

The MX64 motor

• mx64.pdf

• org

Dynamixel example code

We have som code snippets for protocol no 2 for the MX64

• lectrs485dynamixeldyncode.html

• as zip file (3 examples)=

RS 485 design

• Designing rs485

• https://en.wikipedia.org/wiki/RS-485

• TI design guide

RS485 troble shooting

• http://www.windmill.co.uk/rs485.html

• https://www.sparkfun.com/tutorials/215

• http://ltxfaq.custhelp.com/app/answers/detail/a_id/480/~/troubleshooting-rs485-connections

• https://electronics.stackexchange.com/questions/242011/termination-resistor-creating-communication-problem-in-rs485-modbus-tcp

  • just oversee MODBUS word

• MX64 register overview

Slides

• is here

Exercises

We all ned to be in control of our wiring.

RS485 consists of

• a pair of signal wires (see RS485 links above)

• a way ot either

  • have common ground

  • avoid common ground by galvanic insolation (not case in our lab)

• So you need to have TX, RX,GND from your Arduino to the red Sparkfun rs232 to rs485 board

  • check and double check that ( I have seen smoky devices from you the last week)

2)

Start loking at the CC protocol 2 for use in your project