Question about documentation on "last element in TCOMP table"

[meindert.norg]

LS,

 

The Turbo PMAC/PMAC2 Software Reference, page 289 says about "DEFINE TCOMP":

The last entry in the table represents the correction at {count length} distance from the motor’s zero

position. Since the table has the capability to roll over, this entry also represents the correction at the

motor’s zero position. If it is set to a non-zero value, the correction at zero will also be zero.

It seems to me that the last sentence should be:

...If it is set to a non-zero value, the correction at zero will also be non-zero.

or even better:

...If it is set to a non-zero value, the correction at zero will have the same value as the tables last entry.

 

Am I seeing this correctly?

 

regards, Meindert

 

[Sina.Sattari]

Meindert,

 

You're correct. However keep in mind that The correction from the table at motor zero position is zero by definition. this means that the last entry of the torque compensation table must have a value of zero to comply with roll-over capability of the motor and prevent a discontinuity around zero position.

 

Regards,

[meindert.norg]

Dear Sina,

 

Thanks for your reply. I was indeed experiencing a disturbance while moving 'through position zero'. After shifting the complete TCOMP table with the value of the last entry the disturbance disappeared.

 

Am I correct though that the result would be the same if, instead of shifting, I'd set I30 to 1, and then download the original TCOMP (unshifted) table?

 

Thanks, Meindert

 

[Sina.Sattari]

Meindert,

 

Yes, you are correct in setting the I30 to 1 and then downloading your tables.

 

Regards,