How to disable Kinetix drive on Overcurrent or OverTorque

[FreeAtLast]

Hi All,
I have a large servo indexer chassis that uses an AB servo and Kinetix 5500 drive. It seems logical to me to try to limit the amount of damage that the indexing nests can do in the event of tooling in the way during a jog override (for ex). So I've been monitoring these parameters in the PLC to see what their max values are during normal autocycle:

MyIndexer.TorqueReference
MyIndexer.CurrentFeedback

Their max's are 79 and 80, respectively.

Do you know if I should reduce the "Peak Torque Limit Positive" and "Peak Torque Limit Negative" in the axis config in order to put a cap on how much damage the indexer can do?
Thanks for your advice,
Brian

 

[Ken Roach]

What I do is use an SSV instruction to change the "TorqueLimitPositive" and the "TorqueLimitNegative" values, rather than configure the *peak* torque limit in the settings.

Note that you must set the TorqueLimitNegative to a negative value for it to be effective.

I learned that because I was showing off how I could throw a shoulder block and stop a heavy machine, and realized promptly that I had only ever tested it in the positive direction.

 

[FreeAtLast]

Thanks Ken. I see that there is a parameter for "TorqueLimitPositive" and "TorqueLimitNegative" like you say. And that in the axis properties/torque loop there are input fields for "Peak Torque Limit...".
I assumed there wasn't a difference since the values were the same. What's the difference between the 2 (Peak vs non-Peak)?

I'm thinking that the tag I'm monitoring, "MyIndexer.TorqueReference" will give me a good idea of where to set the TorqueLimitPositive/Negative via SSV values. The references are only showing ~80units, so I should be able to bring down the limit from 333units to ~150units.

 

[Ken Roach]

I may be misquoting or misunderstanding the peak vs. limit difference.

Whenever I do an SSV that I don't know by heart, I try to do a GSV first to be sure I know the units / defaults / current values.

On the most recent servo I commissioned, the limit showed (maybe as a result of an auto-tune) as 349.123 % or some other very-close-to-350-but-not-exactly value.

At 350%, that machine hits like a linebacker. At 22%, you can throw it a stiff arm and it will politely fault.

 

[FreeAtLast]

Thank you Sir. I appreciate the tips. I hope to add that GSV/SSV to all my Kinetix drives. Have a pleasant day.

 

[janner_10]

Here's how we set the torque limits on drives:

Remember to: