This might become a bit tricky with stepper motors as there is no good way to control the torque of stepper motors. It would be a simple task with servo motors. In this case you'd just have to switch the feedback resource to the analog input of each axis, set a value between -2048 and 2047 corresponding to the tension and voila but as the 7344 doesn't provide real PID control for stepper moves it will be much harder with steppers. The only way I can think of to do this with steppers would be to write an onboard program that polls the ADCs and dynamically adjusts the velocity by a PID alorithm you write on your own. That's not as tough as it looks like as a PID algorithm is quite simple math. I think you could reach a loop performance of about 2 msec. And yes, you can d
o this with Visual Basic by just calling into the FlexMotion32.dll. Just search the support area of NI for examples
