Home limit All?

[carboncymbal]

In the acorn wizard, I can select an input to be both home and limit for a single axis. I can also set limit all and home all as inputs, however I can not set the input to serve as home and limit all. Right now I only have a single input available. Is it possible to set it to function as home/limit all?

Thanks,
Clay

[martyscncgarage]

In the acorn wizard, I can select an input to be both home and limit for a single axis. I can also set limit all and home all as inputs, however I can not set the input to serve as home and limit all. Right now I only have a single input available. Is it possible to set it to function as home/limit all?

Thanks,
Clay

Clay, it would be good if you created one thread and posted all your questions and follow ups in there.
You can not use HomeLimit with Limit All.
You can use HomeAll and Limit All

If you have one input, just use HomeAll, series all home switches together, and set your soft limits properly
It works well.
Marty

[carboncymbal]

Marty. I'll keep any additional threads to a minimum. Typical forum etiquette is to keep a single thread to a single topic to allow for future searchability. I do worry that the tendency to have threads that are related to a given user/machine rather than a logical topic will hinder the usability of the forum for people searching for solutions, and thus create a greater number of duplicate posts asking about the same topic in the long term.

That said, I'll try to adhere to the etiquette this forum seems to strive for. I do very much appreciate all of the help I have received here, in Particular yours Marty.

Now back on topic. Is there a logical reason that "limit home all" is not an option for a single input? Would it be possible to create this functionality through PLC edits or other configurations within CNC12?

Thanks!

[martyscncgarage]

Now back on topic. Is there a logical reason that "limit home all" is not an option for a single input? Would it be possible to create this functionality through PLC edits or other configurations within CNC12?

Thanks!

I don't remember what machine you have. (this is why its good to keep all your posts in one thread so we can go back and remind ourselves what you are working with)
Home All works quite well if you set the soft limits correctly.
Home sets the machine datum. If you set the soft limits correctly, the control knows the work envelope and keep you with in it. It will stop if you reach the end of the travel in both directions.

Sorry, I don't remember why you feel it is beneficial to do as you are asking.
Marty

[carboncymbal]

Marty,

Ah, I hadn't considered the benefit of the additional context when answering a question. Thanks for explaining that.

In the centroid acorn documentation it talks about the problem with limit and home switches on individual axis. it brings up the valid point that it simply consumes inputs with no real benefit. It seems logical to me that if inputs can serve as both a home and limit, then why not have a homelimitall input option?

Here is the main issue that I see and would like to address. When a homing procedure fails, it can leave the soft limits disabled entirely. Limit switches would provide a backup to prevent overtravel in this case. However, this takes an extra input. Soft limits would seem to be ideal, but there seems to be a somewhat common failure mode where the system configuration permanently changes to remove those soft limits without any indication to the users. A single instance of a failure to home properly in the way that two of my machines were acting could create an undetectable issue that could be present for months before the machine has a potentially catastrophic crash. It does seem fundamentally flawed that a procedure used daily has the ability to remove soft limits if the procedure fails. Ideally such a critical system would not be so readily modified during a routine task.

Additionally, the sensors are already there, so why wouldn't the software permit them to serve as both limit switches and home switches, just as it does for a single axis?

I suppose I'm wondering if this is a feature that could be requested, or if there is a reason I haven't considered why a homelimitall input would be problematic.

[martyscncgarage]

The control treats home and limit switches differently.
What kind of machine are we talking about?
I would suggested you *try* the homeall and the limitall inputs
Make sure you use NC switches or sensors (NPN) The control will check to make sure all switches are closed BEFORE starting the homing process. If any are open, it will fault and tell you so. Allowing you to jog off the open switch and THEN proceeding with homing sequence.

Marty

[cnckeith]

soft limits appear to be zero'd out in only one scenario. that is cancelling of a AUTO SQUARE homing program at just the right place.
to have this experience is common while configuring and testing Auto Squaring, once the machine is configured correctly it is quite rare and even if that does happen can be fixed in seconds by simply restoring a good report.zip file (that was made when the machine was working properly)