Limit Switch Question

[xr4x4ti]

I am making great progress on my Allin1DC install.

I am retrofitting a Prototrak DPM Mill. Here are some pictures for reference.

Mill When I first got it a few months back.

Its current State.

New Electrical Enclosure.

I already have the servos working and moving in the correct direction. I was starting to wire up the existing limit switches and I think I hit a snag. The mill already had a central switch on each axis with 4 wires and I thought that would give me an independent switch depending on which way the lever was pushed. But, I was wrong, one of the wires is a ground. Here is a picture of a switch.

Can this type a switch work? It would get an open contact at both extremes of travel. I guess it would work to home on one side and then use a software limit for the other. But what happens if it overshoots the software limit and hits the switch?

Thanks in advance!
Tim

[tblough]

If you'll look up that switch part number, you'll see one wire is common, one NC contacted, one NO contacts, and a frame ground. That switch might work depending on the travel. The control only allows 1\2 motor turn for hone switch hysteresis. It will be a home/limit switch at one end and you'll need a separate limit switch at the other.

[martyscncgarage]

Picture of the switch doesn't do much good. Take your meter, set it to continuity test, find the pair of wires that show continuity and when you press the switch open (no continuity) you want the Normally Closed Contact and the Common

[xr4x4ti]

If you'll look up that switch part number, you'll see one wire is common, one NC contacted, one NO contacts, and a frame ground. That switch might work depending on the travel. The control only allows 1\2 motor turn for hone switch hysteresis. It will be a home/limit switch at one end and you'll need a separate limit switch at the other.

Marty, Tblough,
Thanks for the feedback.

Yes, I of course already pinned it out and determined exactly what is mentioned above. I guess I didn't make that clear in my original post.

My question is, assuming the hysteresis is acceptable, can the Allin1DC use the same contact for both limits of a given axis? Obviously it will work on one side. But, the switch mechanically actuates both directions. The contact opens if the arm is rotated CW OR CCW. Thus, on the old Prototrak control I am replacing it was the + and - limit switch.

Can I make the two circled values the same number (input)? <-------

Thanks again!!!
Tim

[martyscncgarage]

You really should set it up to have limits on each end of the axis.
Otherwise, set up one end of the axis to be the home and use soft limits to control the other side. (not as desirable on a servo system but would work)

Marty

[tblough]

You can't use the same switch for both limits. When you move into a limit, the control will only allow you to move in the opposite direction to clear the error. If both limits are tripped at the same time (i.e. using the same switch) then you will not be able to move the machine at all.

[xr4x4ti]

You can't use the same switch for both limits. When you move into a limit, the control will only allow you to move in the opposite direction to clear the error. If both limits are tripped at the same time (i.e. using the same switch) then you will not be able to move the machine at all.

This makes sense. I was hoping the control would take into account the direction it was traveling when a switch changes state.

By the way, the software DOES allow you to set both limits to the same switch. But, as you point out, you are then stuck and can't move the axis at all.

I will need to order some new limit switches.

Tim