Kollmorgen Drive??

Howdy all!
Just looking for opinions...

My company deals mainly with AB hardware. We have pretty set range of Kinetix drives and have ventured into the Festo world for a few modules.

A vendor has supplied us with a new machine with a Kollmorgen motor and Drive.

It's the only one in the plant. (so much for build "standards"!)

I'm trying to interface using a CompactLogix 1769-L24 and I'm having some issues finding clear directions for communications.

I'm not sure if we should stick with the unit, or spend the $$ to standardize.

Anyone have any past history with Kollmorgen?
Likes / Dislikes??

Thanks for any opinions!

Howdy Mike! I posted on this thread a while back regarding my experience with Kollmorgen AKD servo drives. My post (#8) includes a link to another Kollmorgen thread. You may also benefit from searching the forum for Kollmorgen Drives.

Hi RonJohn,
Appreciate the reply and the extra info from the post!
I'll check out the Kollmorgen site and see if the AKD we received can be "coaxed" to do what's needed.
Thanks again!

I did a fairly involved high-speed machine a couple of years ago that used a CompactLogix and KollMorgen AKD servos. I used the provided AOI. In general they are fairly well written and documented, and they certainly are easier than interacting directly with the module tag array in most cases. They are designed to be similar to the AB motion instructions, but with several caveats:

1. They are one-shot.... sort of. I found that while the AOI only executes the motion command on the rising edge, it's best to keep the rung energized for a while longer. Weird things happen if you don't...

2. They are exclusive. Make sure you only execute one AOI per axis at a time. If you don't, they conflict, sort-of like a double coil.

3. They are not high-speed. The AKDs might be using Ethernet/IP, but they are not using CIP Motion like AB servos. There is a variation of around 20ms between triggering a command and when the servo executes. This is based on the RPI, and has a lower limit. Works fine for many things, but can cause undesirable variation if you're trying to do high-speed packaging or similar. This is true even if you aren't using the AOIs.

4. A few are oddly unnecessary. The Enable/Disable for example are completely unnecessary, as you can turn the servo off and on using a single bit in the output array for the servo. I looked at the AOI logic, and it's a bit mystifying why they bothered, except maybe to match the AB instruction set.

5. There's that control bit that gets stuck... A number of the AOIs use a bit in the AKD_Axis tag structure call "AxisName".Control.Load_Data_Start_Profile. This bit is used as a one-shot-rising, so if a profile gets interrupted for some reason (E-Stop, etc.), and the bit isn't turned off properly, the next time you try to run the servo won't move. Worse, cycling power doesn't fix the issue. Took me some doing to track that one down. I had to add a rung to unlatch the bit whenever the servo was disabled.

Conclusions: it's much easier to deal with the AB servos. They have their own oddities, but the programming integration is much tighter. But I don't really have any complaints with the Koll-Morgens. Once we figured out the ins and outs, they got the job done.

JRoss said:

3. They are not high-speed. The AKDs might be using Ethernet/IP, but they are not using CIP Motion like AB servos. There is a variation of around 20ms between triggering a command and when the servo executes. This is based on the RPI, and has a lower limit. Works fine for many things, but can cause undesirable variation if you're trying to do high-speed packaging or similar. This is true even if you aren't using the AOIs.

Click to expand...

Good points Jeremy. Let me add that Kollmorgen recommends increasing the minimum RPI to 40ms in circumstances where you plan on being online with the drive via Kollmorgen Workbench software while the drive is in use. This wasn't an issue in our situation.

On a plus side, they offer a servo motor (type AKMH) where the power & feedback are combined into one cable. Works well & makes electricians happy!