What is the speed control logic within NI9514?

[ZeSuli]

Hi guys,

I'm using NI9514 to control a servo mortor, but the control logic just confuses me. I used Straight-Line-Move block to give a certain velocity to motor and the motor does follow the velocity(though with oscillation in a small amplitude). But what's strange is that there is no velocity control loop in the axis configuration, so what is the real thing that's controlling the speed? Is it that the velocity just got integrated to position? The axis configuration is listed as below. Any reply is appreciated!

Best Regards

[ZeSuli]

Hi guys,

A problem has been confusing me when I'm doing some test with NI9514 and AKD servo drive: I used Straight-Line Move to give a certain velocity to the motor which is configured with velocity mode in servo drive, and the motor ran properly. But in the axis configuration there is only position control loop, so where exactly did my velocity input go into, and is there anything to do with the position PID controller here? If I choose to control the position, does it mean both the position control loops in this axis and servo drive will work at the same time? The axis configuration and block diagram of position and velocity mode in the servo drive software Kollmorgen Workbench are shown below. Any answer is greatly appreciated!

Best Regards

[JÞB]

In velocity mode the drive will run at the set Velocity Until the position is met (acceleration and deceleration requirements observed)

In position mode the drive will run as far as the position set up to the specified max Velocity (acceleration and deceleration requirements observed)

In practice,  there is no observable difference .  Just a point of view for the programmers. 

[ZeSuli]

Hi Jeff·Þ·Bohrer,

Thank you for your reply. I don't quite get your point. What if I set the drive to position mode, will there be two position control loops working at the same time?

Best Regards

[ZeSuli]

Hi guys,

I'm using NI9514 to control a servo mortor, but the control logic just confuses me. I used Straight-Line-Move block to give a certain velocity to motor and the motor does follow the velocity. But what's strange is there is no velocity control loop in the axis configuration, so what is the real thing that's controlling the speed? Is it that the velocity just got integrated to position? The axis configuration is listed as below. Any reply is appreciated!

Best Regards

[RavensFan]

Is LabVIEW involved in any way in this question?

Is it a different NI product?

It seems that if this question should be part of a different forum.

[ZeSuli]

Hi RavensFan

Thank you for the reply! Yes you're right. Sorry for posting this in LabView topic and I will try asking for help in another topic.

Best Regards