Kinetix300 controlling MPL-B1530U losing position

Hello everyone,

I'm currently losing my mind with the loss of home position of a MPL-B1530U servo motor, controlled by a Kinetix300, with instructions coming from a ML1400.
After each cycle of the machine I have to remake the homing of the engine, because I lose the mechanical position. Mechanically I have controlled the Axis that is being driven by the engine, and all is OK.
If I look at the MotionView of the engine, I don't get any position error, or any kind of errors for that matter. At all times, the engine is using up to 15% of utilization (from the monitor panel).

maybe you guys have some ideas on what should i controll.

thank you.

What type of Homing method are you using? Are there limit switches at the ends of travel, a dedicated home switch, an index pulse, or zero reference from the motor feedback device, or a combination of all?

Is this a new application or something that was proven to work but no longer does?

1. Are you absolutely sure you aren't mechanically slipping
2. Can you see in the program if it is possible to rehome or define a new position (that might be happening when you don't realize it)

lezeur said:

Hello everyone,
...the loss of home position, a Kinetix300
...lose the mechanical position.
...the engine is using up to 15%

Click to expand...

[loss of home] [lose the mechanical position] There is a difference between "loss of home" and "not where I expect". In MotionView, check the "Homing Status" on the Homing page. It should read "Homed" in green. If your machine makes a cycle then the homing status reads "Not Homed", then something is very wrong, call Allen Bradley. But if it is not in the position you expect, and the homing status remains "Homed" then maybe focus on drive configuration. I have found that positional problems are usually related to the values entered for User Units, scaling, offsets, homing setup, etc. You might run the machine cycle very slowly to make observations.

[up to 15%] Normal


I understand that you need to make this project work. In the future, consider the CompactLogix and Kinetix5500 are an improved solution. They cost more, but they will save you time, especially in troubleshooting.

@dmargineau
I am using a dedicated home switch, and for protection we have dedicated limit switches.

@kekrahulik
It is a old application, that worked for almost 1 year without any issues. I am very sure there is no mechanical issue, because I double checked it with a mechanical colleague. (The engine is moving a Nadella axis, in the past we had issues with them, but this one is OK) I decreased the speeds of the movements, and took the machine in a step by step mode, and I still have the same issue. I am not giving a rehome comand, or any strange comands for that matter. On the right side of the machine I have another axis, doing the same work in parallel, and that one is functioning perfectly. Same setup for both axis, on both Kinetix and PLC.

@microdesigns2000
To quote you here, the problem is more like a "not where I expect".
The machine is at all time in Homed. For me the Kinetix works fine on the other axis installed on the left side of the machine. I've tried "playing" with some of the values like break delays, etc. But no results.
I know that CompactLogix is way better, but the customer insists on using ML1400.

Thank you guys for the suggestions again,
Lezeu.

lezeur said:

...but the customer insists on using ML1400.
Lezeu.

Click to expand...

Then the customer should be fine with this 'shot in the dark' type of troubleshooting...

The Kinetix 300 will run 'good enough' controlled by a MicroLogix controller, however, troubleshooting messaging control is next to useless...Are you sure nothing gets 'hung' or triggered inadvertently?...I understand that you have an identical setup running without any issues but isolating the culprit on the malfunctioning one would most like require individual components replacements and re-tries...

What type of encoder is installed on the motor- incremental type or absolute?

If absolute, is it the same type motor the drive was originally commissioned with?

We have previously asked you what type of homing method you are using; there are 15 available types (see table at page 115 of http://literature.rockwellautomation.com/idc/groups/literature/documents/um/2097-um001_-en-p.pdf)

Again, which Homing Method are you using?

lezeur said:

@dmargineau
that worked for almost 1 year without any issues.

Click to expand...

It is hard to discern if you are having a design-related problem, or a failure-related problem.

If the other axis is working fine, is the hardware identical? If you really can't find anything mechanical like a loose coupler on a gearbox, maybe start replacing or swapping parts to see if the problem moves.

On the other hand, sometimes an end user will not report problems for a long time. In this case, the problem may have always existed? How severe is the issue?