7071
General Mach Discussion / Re: axis changes from + to - by itself
« on: April 25, 2011, 02:23:10 AM »
If your controller is not recognizing the direction signals correctly then the motors could rotate in the wrong direction. This situation can occur when the controller is expecting the full 5 volt TTL signals for it's inputs but the computer's LPT parallel port is only outputting 3.3 volt TTL signals. In many cases this depends on the operating threshold of the opto isolators used in the breakout board so it may be a good idea to measure your parallel port direction pin voltage and and if it is not the 5 volts TTL standard (0 volts when jogging one way and 5 volts when jogging the other way) check that your BoB is compatible.
Just a thought.
Tweakie.
Just a thought.
Tweakie.