Kinetix 6000 Aux Feedback

I have a Kinetix 6000 drive linked to a controllogix processor via SERCOS. I have a 1024PPR encoder hooked to the Aux Encoder Feedback of the drive. This encoder monitors the rotation of a press. For example, I have the encoder scaled to give me 0-360 deg of rotation. Now, I have a question about the setup of this Aux Feedback group.. I don't know if this axis should be setup for linear or rotary.. If you select rotary, there is an unwind function that I am not sure what it does.. Can anyone explain this unwind feature to me???

Sometimes it seems that my encoder counts may be getting off.. So, I wander if the unwind could be causing a problem.. Should this axis be setup for Rotary or linear..

Thanks,

I think if you dig deep enough in the help documentation, the reference to linear means linear drives, not linear encoders.

Not sure of the unwind feature...

I would assume rotary.
Unwind is the value that you can add or subtract to the axis position to reset the axis to starting position without really moving the axis. Have a good read of the help files including the glossary of RSLogix5000 and also the motion instruction book.
Regards Alan Case

I read through the help but I didn't find anything to help me.. My conversion number is 2,000 and the undwind is 72000.. Will this unwind affect the encoder etc... Basically, I just want it to read 0-360, then 0-360 each time.. I really don't need unwind.. Do I need to make that number 0 or do I even need to worry about it... If I rotate the encoder, it appears to do what I want.. But, it seems after it runs awhile, it may be getting off.. I just wanted to know if the unwind could be causing a problem...

Sounds more like you need a homing signal. ie in 1 rotation it may be out by 0.01 degrees, (not enough to notice) but in a 1000 revolutions it will be out by 10 degrees. Every time the press revolves past 0 degrees the axis will home ie set itself at zero. Don't take this info as gospel as I would need to actually see more of the application to accurately diagnose.
Regards Alan Case

plcengineer said:

My conversion number is 2,000 and the undwind is 72000..

Click to expand...

Where did those numbers come from?

plcengineer said:

Will this unwind affect the encoder etc...

Click to expand...

Yes

plcengineer said:

Basically, I just want it to read 0-360, then 0-360 each time.. I really don't need unwind..

Click to expand...

Then it is a rotary axis and yes, you do need to get the unwind count correct.

plcengineer said:

Do I need to make that number 0 or do I even need to worry about it... If I rotate the encoder, it appears to do what I want.. But, it seems after it runs awhile, it may be getting off.. I just wanted to know if the unwind could be causing a problem...

Click to expand...

A 1024 PPR encoder will result in 4096 counts/rev in the controller. If one rev of the press is one rev of the encoder, then your unwind count should be 4096 and your conversion factor 4096/360. (counts per degree)

Does the axis driven by the motor move continuously with no end limits? (like a conveyor or roller) If yes, then you should choose rotary. If the axis that is connected to the motor has end limit positions, then you should choose linear. There may be exceptions, but that's the rule of thumb.

Sir, can i ask what is the encoder you are currently using? specifically the part number. tnx

Under the drive motor tab, is the drive resolution sat for 72000 as well.
I checked my settings and I have both sat at 720,000 along with the 2000 conversion constant and my type is rotary. Mine is a Kinetix 6200.

1. If you are looking for a 0-360 then you want rotary.

2. Is this the encoder feedback for the motor or is this the position of the press?
-> If it is not used for motor feedback, then I recommend that you create an additional axis called "Press" of Data Type AXIS SERVO DRIVE.

*****On the general tab:
axis configuration = feedback only
motion group = (whatever your motion group is named)
Module: the drive that the encoder is wired to the aux feedback

*****On the units tabs
units = degrees

*****On the conversion tab
select rotary (don't worry about the values now)

*****On the Aux Feedback Tab
TTL Feedback Type
1024 per Rev

*****On the Drive/Motor Tab
I recommend you have "position feedback" as Attribute . You may want Velocity FB as Att#2
Use the calculate button to detemine your values
360 position units (degrees) per 1.0 Aux Rev
360 position units (degrees) per 1.0 Unwind Cycle
Click Calculate
Click Update to have it fill the values into the conversion tabs fields

*****On the homing tab
homing must be passive (i think)
Position = whatever value you want home position to be (0-359.99 degrees)
Sequence = immediate


I think that should get you pretty well setup.

You will need to either home the axis with an MAH or redefine position with MRP. If you don't MAH, the homed status bit will not get set, but it proabbly won't hurt you unless you use the homed status bit in your code.

Hope it helps.

Good Luck

This is a thread that sat dormant for 7 years until binarramil resurrected it with an unrelated request for an encoder part number. He did the same thing to 5 or 6 other threads, as well as opening his own new thread.

I realize it's Phil's forum and this probably isn't a trivial task, but I think that threads should be locked after 1 year, so they can be linked to but not added to.

The practice of appending an unrelated question to an old thread is frequent novice behavior but it wastes time and doesn't lend itself to easy-to-understand information in the threads.

I didnt notice it as well. I noticed that the above offender had tried to hijack 4 or 5 other posts but I missed this one.