Re: [CAD_CAM_EDM_DRO] what is the differance in drive and amplifier?

irfan_younis wrote:

>Hello users,
>What is the difference in servo drive and servo amplifier?
>
>

It is hard to say. These terms are used by different people to mean
different things, and have slightly different meanings in different
industries.

But, let me explain some more specific terms.

A servo amplifier is generally taken to mean a device that takes some
signal in (the command), and drives a motor of some sort in a manner
such that the error between the command and some sensed value is
minimized. The traditional use in machine tool control is the velocity
servo amplifier. A motor fitted with a tachometer is driven such that
the velocity sensed by the tachometer is held exactly proportional to
the velocity command sent by the CNC control.

So, in this context a servo amplifier takes in an analog signal and produces
power to the motor.

But, some companies have made units labeled servo amplifiers, but they
took digital commands, PWM velocity commands, or whatever.

In the hobby and low-cost CNC market, servo drive pretty much
means a device that takes in step and direction signals, and drives a DC
brush motor to move the requested number of encoder counts. See the
Gecko 320 for an example of this type of drive.

But, in the industrial motion control business, a servo drive could mean
any sort of device that controls a motor that has some type of feedback,
not necessarily position feedback. So, you really have to know the
application
or the type of drive to know whether it is a positioning servo, or just a
speed servo. It could also be a torque servo. As for command schemes,
there is everything from analog velocity and step/dir to CANbus and other
digital networking protocols. And, of course, many drives from the late
70's to the 90's used proprietary digital communications protocols that
may or may not even be published. Manufacturers are going to standard
protocols, now, thank goodness.

Jon