AB Ultra3000 servo question

[shilok]

Hello everybody,
I've got single axis Ultra 3000 continuous motion servo motor but
can't figure it out how to manipulate [size=-1]deceleration.
It is controlled stop, but I would like to make it coast longer
(right now it's about 0.25s where I would like it to be at 2s)
The only settings I see is at drive/presets/[/size][size=-1]deceleration,
but changing that value does not seem to change anything.
On the other hand acel can be changed with no problems.
There is no break or anything like that just the load of the machine.
Maybe I'm expecting too much, I'm used to VFD's where you
set your decel in seconds and that's it.
Any ideas are welcome.
[/size]http://www.thefreedictionary.com/deceleration

 

[OkiePC]

What is the part number of the drive and motor you are using, and what type of control interface do you have?

 

[shilok]

Motor-MPLA430PMJ22AA (allen bradley)
Ultra 3000 servo drive - 2098DSD030X
I'm using Ultraware v1.64 to communicate with the drive.

 

[OkiePC]

I am vaguely familiar with ultraware and ultramaster, and I recall having similar issues.

Is your indexing drive configured for positioning? indexing? analog signal follower?

I think there are even more choices. What are you doing to trigger the stop/start control?

Certain parameters cannot be changed while the drive is running.

The drive and motor is certainly capable of doing what you want, but you will have to uderstand how it is configured. Make sure the motor selection is correct and the number of pulses per revolution is correct.

I seem to recall, that you can things all out of whack by scaling your units incorrectly on one tab, then find out that what you think is a certain distance or velocity is totally incorrect.

You may have to specify your deceleration in units other than time. I cannont remember much more. I think I still have the software at work, but someone will probably help you by the time I get in the office tomorrow.

Good Luck!

 

[OkiePC]

Yes, I just found a manual, and you will be setting up your decel rates in units of [user units]/sec^2, not seconds.

This can be a confusing term to understand.

It is a rate, not a time. It is a distance per second, per second.

And the manual makes it worse by showing units in the graphic screenshot of revs/sec^2, and then describes the acceleration and deceleration properties (preset speed mode) as counts/sec^2. Actually it won't be counts unless that is how you configure your user units. Maybe that is the default drive state?

Whichever it is, it is not time, but rate, so a smaller value will make for a softer decel.


And it will be a very tightly controlled trapezoidal profile too, much more precise than the VFDs you are used to.

IIRC, and assuming preset speed mode, you will need to have a preset with a velocity of zero selected in order to ramp from a preset speed to a stopped (locked rotor) condition using the deceleration parameter on the preset config tab. This is an old memory from the Ultra 100 and 200 series, and may not apply in your case.

Paul

 

[shilok]

Hey Okie,
you're right, units are revs/sec2, not seconds.
But it's not indexing motion,it's just continos running.
Drive is set as preset velocity (few presets for diferent speeds)
and I can adjust acel from preset velocity input limits tab, but
the decel modification from the same tab are really not changing anything (and I tried values from 0-some huge numbers)
I was hoping there are some other tab that I'm not seeing.
I'm sure it's something silly, but still...

 

[OkiePC]

Yes, then you are on the right track

The decel on the page you are adjusting will work when going from one preset speed to another.

There is another separate decel rate for stopping.

I think it is the deceleration limit, which may also be the accel limit.

That is the reason I ended up creating a preset speed of zero and using that instead of stop to gain the extra flexibility in configuration choices.

I set my drives up so that no inputs triggered preset 0 (or 1, can't remember), and then my 2 other speeds were selectable with hardwired signals.

How are your preset triggered? Hardwired?

​

Deceleration If Accel/Decel Limits is set to Active, this is the drive's​

deceleration limit when:​

• the drive is in Preset Velocity operation mode (as set in​

the Basic Drive Setup window) and​

• changes in the Preset Select Line 0, 1 or 2 settings​

result in a change to a lower Preset Velocity value.​

This value has a range of 0 to 2147483647 counts/sec2.

​

​

Since you have an indexing drive, maybe this parameter comes into play?

Abort Index Deceleration The deceleration used to stop motion when the Stop​

Index input terminates an index move.​

​

​

​

 

[mirang85]

I need to know how to change the posicion on the index in Ultra3000 Servo-Drive , or how can I have different positions index to move the servo-motor to different positions , all of this is working with a CompacLogix . Thanks .

 

[kolyur]

Assuming it's the indexing version of the drive (model number ends in 'X'), you will need the Ultraware software and proper serial cable. Motion profiles are set up in the 'Indexing' window in Ultraware.