You Just have to LOVE eBay

[Stevie]

I just snagged me 2 of these; wow
I have the basis for 2 3 axis systems right there

The 4113 provides three independent current amplifiers. Each amplifier channel can also drive one brush motor in multi-axis applications
Each of the three channels of the 4113 can drive an independent motor
or inductive load. (These may be dc brush or other single-coil motors, or
multi-coil motors such as stepper or brushless motors where the coildrive
signals originate in an external controller)
Can anyone explain just what that means i bracketed (mainly external controller)

http://www.warshipmodels.com/~SteveN...copley4113.pdf

I got the 2 NIB for $*.** each or basically free

[Al_The_Man]

Nice! 'where the coil drive originates in an external controller' refers to motion control cards etc. such as Galil & Acroloop where two comutation phases are supplied to the drive for AC servo's. I think in this mode two amp inputs would supply one motor?
Al

[Ken_Shea]

Dear Stevie and Al_the_Man


What ??????

[Stevie]

Thanks Al; or i think so; I'm still in the dark
Well at least they were cheap

[Al_The_Man]

Looking at the Copley manual again, It looks like they only show an example for connections of three DC motors , they claim the amp can be used with steppers & BLDC motors as well. But there is no information as how you would configure the amp for multi-coil motors?
Al

[Stevie]

And thats why I'm in the dark

Maybe an email to colpey
But they are not that friendly i have found in the past

[Stevie]

Notes Important: Transconductance amplifiers produce torque in a motor, and this in turn produces acceleration.
Velocity is not controlled. An unloaded motor will spin-up to its maximum speed when torque is applied. Velocity control is produced by feedback from the motor to the control system and not within the amplifier.

now this is an interesting note from the .pdf

[Al_The_Man]

Originally Posted by Stevie Notes Important: Transconductance amplifiers produce torque in a motor, and this in turn produces acceleration. Velocity is not controlled. An unloaded motor will spin-up to its maximum speed when torque is applied. Velocity control is produced by feedback from the motor to the control system and not within the amplifier.

In electronic terms,a transconductance amplifier is one that converts a voltage into a current. What they are saying is that the amplifier is not configurable in the velocity mode where for example tach feedback would be required.
This method was used in the earlier days of motion control and the tach feedback was set up first and called the inner feedback or velocity loop, the outer feedback loop was from motor to motion controller via encoder.
The prefered method now is the torque or current mode of operation for a servo amplifer, where the only feedback is supplied by an encoder for example to the motion controller. The amplifier is controlled by an input analogue voltage which relates directly to an output current.
It is also important with a torque operated amplifier, that it not be enabled untill the motion control device is ready at power up, and to disable the motor amplifer first at power down. Otherwise the motor can take off during the power up, and power down period.
Al

[Stevie]

Hah

So if the motor tach is feeding the controler and the amp takes the commands from the controler; which completes the loop; but I still am missing the Velocity control; what or where is it coming from to control the Velocity; is that not part of the overall system

Servos are total new to me; the control and feeding/care of is just not in my experiance "yet"

[Al_The_Man]

This amp. does not use the tach feedback principle at all, the torque/velocity is totally under the control of the motion control system, which relies on feedback directly from whatever method such as an encoder. The velocity that the motor travels at is whatever has been asked of the motion controller and it applies the appropriate signal to the amplifier in order for it to deliver the required torque, based on this encoder feedback.
Al

[Stevie]

Thanks Al; I think it's starting to all settle in my old gray matter now

So I need a motion control board to use in conjunction with those 2 3 channel amps

Ok i guess it's back to eBay and see what I can dig up

[Stevie]

eBay item #3869097992

chk out this one i nabbered; now this one can do just about everything I need
Also it takes step and dir input