Dynomotion Forum

Tom,
I thought i understood your reply to this question but i obvously do not.
With the machine motion control issues i want to check the velocity response of the axes and go back to the beginning.
I have attached the configuration for the Y axis.
I have attached the step response configured how i think i understand
9 volts = 1842 DAC output.
The axis maximum velocity for 9 volts = 150000 counts / sec = 150.000 mm / sec.
Acceleration = 150000 counts per sec / sec = 150.000 mm /sec /sec.
Jerk needs to be very high so response is trapezoidal.
I would start by commanding a move of 50000 counts / sec = 50.000 mm /sec and then adjust the servo amplifier to match the commanded velocity to the actual velocity.

Where am i going wrong ?

I have read the help section on configuring an open loop spindle and with the example settings and no encoder input i get what i expect on my Y axis but obviously i need to see the actual axis velocity to make sure the velocity loop is tuned correctly.

Regards,
Tim

Hi Tim,

I'm not sure what you are trying to do. But with a Velocity FF of 1842 it will output the 9V at a velocity of 1 count/sec. But you are commanding 150,000 counts/sec. So as you see in the plot the output immediately saturates at 10V. The axis moves at its maximum speed of ~150000 counts/sec and then soon gets a following error. You probably want to set the VFF at:

2047/150000 = 0.0136