Saturday, 17 August 2013

Two brushless DC ROV thruster motors controlled independently over an RS485 link

Having modified the LabVIEW GUI (Graphical User interface) code and the BLDC (Brushless Direct Current) ESC (Electronic Speed Controller) firmware I can now control multiple motors independently over the same RS485 link using addressing.

The first part of the meassage on the serial link specifies the address, with a value from 0 to 15 and only the ESC that has that address, based upon four jumpers on the ESC PCB, will then use the following value in the message to control the speed and direction of the brushless DC motor it is attached to. If it isn't the right address it then simply ignores the message, until its message comes along.

A message is transmitted from the GUI software to one ESC, then the other, then back to the first one, continuously, at about 50ms (milliseconds) per message.

Here's a short video of the GUI and the motors in action.

Sunday, 11 August 2013

Two thruster motors controlled by RS485

Not exactly a giant leap forward but it's all about slow deliberate steps for me, with as much testing as possible in between.

So here is a video of two thruster motors, two BLDC motor controllers made by my own fair hand and a LabVIEW programme basically telling them how fast to go and in what direction over an RS485 link.

The oscilloscope at the end is just showing the communication on the RS485 channel.

Next step is to provide independent control to each motor so they're not quite as synchronised as they are currently :)