TMS320F28069M: Spintac POSMOVE rollover problems

Daniel Rush

Part Number: TMS320F28069M

When using POSMOVE to do point-to-point position control, if the commanded position coincides with the cfg.ROMax_mrev, e.g. the rollover number is 10 revs, and I set the position to 10 revs, if I set the next position to go -5 revs(back to position 5 revs), the POSMOVE API doesn't have the concept of rollovers, so it will sometimes behave correctly and go down to position 5, other times it will jump to the next rollover(jump to position 20, then create a plan to go down to 15). How do I get this to always behave correctly, why doesn't POS_MOVE have the concept of rollovers as an input?

over 7 years ago

0 Yanming Luo over 7 years ago

TI__Guru** 116110 points

You must ensure the Pos_mrev between -cfg.ROMax_mrev and cfg.ROMax_mrev when you set or change the Position Plan. That's a limitation condition in spinTAC function, you must be aware of the bounds of this signal, it will immediately go to the minimum value when the position signal reaches the maximum value, the minimum value is the negative of the maximum value.

0 Daniel Rush over 7 years ago in reply to Yanming Luo

Intellectual 585 points

I understand what is happening as I see it experimentally, but how do I make this behave correctly? This seems like a problem that should have been noticed in development and accounted for.

0 Yanming Luo over 7 years ago in reply to Daniel Rush

TI__Guru** 116110 points

Yes, you need to know the current position and the target position if both positions exceed the limitation in development, it seems like this is the only way in the existing example project.

C2000™︎ microcontrollers

C2000 microcontrollers forum

TMS320F28069M: Spintac POSMOVE rollover problems