Hey guys,
I am trying to write a low level serial communication VI for reading speed from a dynamixel using labview and the myRIO. The VI I use to do this (attached below) works on the first iteration returning the correct number of bytes that are expected. If I put this VI in a while loop, it will never read in the correct number of bytes the second time throwing an I/O error -1073807298. Since the dynamixels use RS485, I am using a MAX485 chip to convert TTL (RX and TX) to RS485 which means I'm using a digital IO pin on the myRIO as the enable. I have had no issues writing to the dynamixels, only reading. It seems strange that it reads fine the first time but not the second since no data is transferred from one iteration of the VI to the next. Essentially I want to enable TX, send the command for reading speed, enable RX, read in the response to the buffer then read the bytes from the buffer. I have no idea why this isnt working. What is going on here?