TMS320F2800157: start profile have a big different for first startup and restart

zcwbj

Hi TI team:

I found a very big different of the start profile for the LEVLE４（Fast LIB ,Universal motor control lab) as below.

The first time start (after power up reset ) is start very smooth without speed overshoot ,the "motorVars_M1.speed_Hz" can follow the "motorVars_M1.speedRef_Hz " vey good .

The 2,3,4,is restart after stop, the restart with big speed overshoot ,and after 15 seconds later, the "motorVars_M1.speed_Hz" can follow the "motorVars_M1.speedRef_Hz " .

so is some parametes need to be reset after restart .

Please help to provide some suggestions ,thanks a lot !

over 2 years ago

0 zcwbj over 2 years ago

Prodigy 80 points

It seems the startup profile is very unstable , every time have big different , how to fix the issue .please help

0 Jason Osborn over 2 years ago in reply to zcwbj

TI__Genius 11076 points

Hello,

I've got a couple of questions to start us off.

Have your run incremental build 1, 2, and 3 prior to running build 4?
How are you turning off the motor each time?

Regards,
Jason Osborn

0 zcwbj over 2 years ago in reply to Jason Osborn

Prodigy 80 points

1 . Yes，I have run the cincrementtal build 1,2,3,4 the programm works normal

2. I didnot change the turn off strategy ,it is should as previous as the sdk . Do I need to change the turn off strategy and how to change the turn off strategy

0 Jason Osborn over 2 years ago in reply to zcwbj

TI__Genius 11076 points

Apologies for the confusion. I was not suggesting you change anything yet.

What exact steps are you taking to turn the motor off each time? There's several possible things you could be doing, such as setting the speed reference to 0, setting the enable flag to 0, or resetting the device entirely, and I'm trying to figure out which of these steps you're taking. This will help me debug the situation.

Regards,
Jason Osborn

0 zcwbj over 2 years ago in reply to Jason Osborn

Prodigy 80 points

hello Jason:

what is the possible reason for overcurrent during the startup period . how should I to tuning to solving this issue

+1 Jason Osborn over 2 years ago in reply to zcwbj

TI__Genius 11076 points

Hello,

Without further details, I'm not certain.

Were you able to determine the answer to the question I asked in my previous post?
Is this issue present in Build 3 as well?
Are you certain that the physical motor parameters that you've set in user_mtr1.h are correct?

Regards,
Jason Osborn

0 zcwbj over 2 years ago in reply to Jason Osborn

Prodigy 80 points

Hello Jason:

I think this issue is relate with the mode of the pwm.

if you use the DPWM for fast , it will have some proble when startup .

if you use the SVPMW, the start performance will be better.

+1 Jason Osborn over 2 years ago in reply to zcwbj

TI__Genius 11076 points

Thank you for the update. I'll go ahead and mark this thread as closed for now, since it seems like you've tracked down the source of the issue.

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TMS320F2800157: start profile have a big different for first startup and restart