Trajectory Generator reset to a postion, not 0

[Massif]

   Hi,

My VI is base on the example "Servo Psoition Loop".

I have an sensors in the middle of my trajectory. I would like to change the value of my position with the real position of my sensor. (In order to reducue the position error of my machine) 

I reset the axis position to a new one (not necessary zero), without change is trajectory. For that I reset

   ->the trajectory generator position

   ->the encoder position (Reset position Axis 1)

   ->the position set point

The position is correctly reset but the trajectory is change and go to this postion instead of continue is move.

I would just update the value encoder without discontinuities in the trajectory.

How to do that?

 

I have read this message that can help:

http://forums.ni.com/ni/board/message?board.id=240&message.id=7053&requireLogin=False

  Massif

[ElRambo]

Hi Massif,

What hardware do you use with this VI ? A CompactRIO, a CompactFieldPoint ?

I guess, that you are using FPGA based hardware to control your drive.

In this case, I would suggest you to send new position data to the FPGA VI that retrieves the encoder position.

But such a configuration may generates some conflicts, you'll have to handle this.

Thanks for posting on NI forums.

Have a nice day.

Regards,

[Massif]

Hi Maxime,

I use a cRio 9024 with a FPGA target with the slots NI9263 and NI9411.

I tried to update the FPGA target

   ->the trajectory generator position

   ->the encoder position (Reset position Axis 1)

   ->the position set point

   ->the spline data

But I still have some issues.

I think there is conflict inside of the FPGA. 

When I reset the position to 'x' value, the motor  run to this value instead of update the value and follow is trajectory.

You can find my project enclosed.

  Regards 

  Massif

[ElRambo]

Hi Massif,

I think that the only way to do what you want to do is to update the encoder position in the Servo Position Loop (FPGA).vi

You'll have to modify the loop that handles the encoder position,  and then if your sensor is activated, you'll use this information to change the encoder position value.

Have a nice day !

Regards,