73xx Direct Analog Control / Current Control of AKD drive

[Jed_Davidow]

My customer has brought me a NON-EtherCat PCI-7358->7774->AKD drive setup.

They have requested "Torque Control" and while we do have an external Torque sensor, I have finally determined that, at this point, they simply want to directly dial in a motor current.

Can this be done via LabVIEW (2015, NI Motion)?

• Can I directly set Motor Current based on the MAX Setup?
• Can I directly set Analog Output?
• Can I get the system to handle accelleration/decelleration/jerk/etc in a Current-Based mode?

I have found the info on how to hook up an external torque (or other analog sensor) to use as feedback control.  I am FRIGHTENED to bridge the 73xx analog output to that port and map the system 1:1, but that seems like a possibility, if no software method can be found.

Thanks!

[Catatina]

Hi Jed! 

Thanks for posting in the forums. It would be helpful to know what type of motor your customer is using. 

If it is a stepper motor, it's important to note that they only ever run at two different current values, running and idle current. Both of these values are set when using the NI Stepper Configuration Utility. 

The running current is applied while moving and for a certain period of time (also configurable) after a move has stopped. The idle current is applied when the motor is not moving. What this means is that you don't need current feedback from the drive since you will already know the current because you will know if you have commanded a move.

Also keep in mind that steppers are not like servos. Servos run control loops that will increase or decrease motor torque depending on how much external torque is applied to the motor. Steppers will always run at either the running torque or the idle torque. They do not adjust their torque based on the motor load.