Re: +/- 10V Gecko

Hi,

Servo amplifiers can operate in velocity mode, torque mode and
sometimes IR compensated mode as well. The mode determines how the
control input (+/- 10 volts) is interpreted.

Velocity Mode:

In velocity mode the amplifier outputs a VOLTAGE that is proportional
to the control input. It is called "velocity mode" because the motor
speed is roughly proportional to the voltage applied to it. This is
the same mode that audio amplifiers use.

Torque Mode:

In torque mode the amplifier outputs a CURRENT that is proportional
to the control input. It is called "torque mode" because motor torque
is proportional to the current passing thru it. By analogy, a car
engine is a torque mode amplifier and the gas pedal is the control
input.

IR Compensated Mode:

This is a variation of the velocity mode. The motor SPEED is
proportional to the control input. Its purpose is to operate as a
regulated speed control. Motor load (current) is sensed and summed
with the input as positive feedback. The right amount of feedback
will increase the output voltage just enough to compensate motor RPM
drop with load. This makes the motor speed independent of load
(within 1%).

Most servo loops use the amplifier in the TORQUE mode. This mode
gives the widest closed loop bandwidth (lowest response time)and is
more stable than servo loops using VELOCITY mode amplifiers.

Mariss

--- In CAD_CAM_EDM_DRO@y..., "Tom Eldredge" <harmonyt@r...> wrote:
> Thanks to you, Jon, Mariss, Matt, and the others who have clarified
the
> issues on this servo thread. It has helped me to clear up some
sloppy
> thinking about servos. I will still need to understand the
difference
> between torque mode and velocity mode.
>
> I know that is why guys go to college. I never really had that
option, and
> still don't. This forum has been a wonderful help to me.
>
> Tom Eldredge>