Moving from Soft limits to hard limit switches

[PeteJ]

I currently have a 3 Axis CNC retrofit with an Allin1DC. We had issues with the original limit switches and as part of the upgrade soft limits were put in place in order to expedite the upgrade. The catch was that when I shut the machine down I had a macro written that I use to home the machine before shutting the controller down. Per the recommendatoin from the support person at Centroid I have purchased and installed hard limit switches and want to get them wired up and use them for the machine home and leave the soft limits in place for the other end of travel (link to the limit switches is below). Prior to randomly wiring in the limit switches I want to make sure I do it correctly.

As I under stand it looking at the manual, I need to wire each appropriate axis to the appropriate INP"1-8" using a normally closed contact. The question is how do I disable the soft limit for home while leaving it inplace for the end of travel when the machine is running?

(https://www.automationdirect.com/adc/sh ... %20Sensors)

[cncsnw]

You do not need to disable soft limits while homing.

First, soft limits do not apply until after machine home has been set.
Second, soft limits never apply to M91 and M92 moves.

If you only have one switch per axis, then you will only connect to three inputs (either INP1 or INP2 for X; either INP3 or INP4 for Y; and either INP5 or INP6 for Z). Which one you use for a given axes depends on which direction you want that axis to home, and whether or not you needed to set Direction Reversal for that axis.

You will need to turn off (open) the limit defeater DIP switches for the three inputs you connect.
You will need to leave the limit defeater DIP switches for the other (unused) three limit inputs turned on (closed).

[PeteJ]

Thank you for the quick reply, I wil give this a try tomorrow.

[PeteJ]

The NC Contacts on the limit switch are both black wires (11 and 12 per the attached image). I am only using these new limit switches for X and Y, Z will use the previously configured setup for now.

Looking at the schematic for my Allin1DC, as I am reading it one wire off the limit switch will need to go to TB1-12 (X Limit) and TB1-13 (Y Limit) and the other black wire will go to either INP1 or INP2 for X; either INP3 or INP4 for Y.

Being that they are both black wires I have no way to tell which is on each end of the contact of the limit switch. does that matter which wire got to to the TB and which goes to the INP connection?

[tblough]

It makes absolutely no difference. A switch just connects the two wires and doesn't care which end is "in" or "out".

[PeteJ]

I have the switches connected and when I manually activate them and recognizes the appropriate limit switches. I have also gone into the config using F1(setup)>F3 (config)>F2(machine)>F4(Set Home) and set all the axis home positions.

When I use the F4 (set home) it says "Unable to find home switch" .

I've attached pictures of how the limit switches are configured in the software and where the dip switches are set. I know that there is a mismatch somewhere I just cannot figure out what combination is correct.

[cncsnw]

Because you have set Direction Reversal = Yes for your X axis, you need to use INP2 for the X- limit/home, and INP1 for the X+ limit/home (if any).

Swap the minus and plus numbers in both the "Limit" and "Home" columns, and move your wire from INP1 to INP2.

I assume here that you have installed the X switch at the minus end of X travel. Since you have not told us what kind of machine this is, or where your switches are located, nor even posted a Report, that is just a guess.

Which directions do you intend to home the axes?

[cncsnw]

You also do not appear to have turned on the limit defeaters for the limit inputs you are not using.

Supposing, hypothetically, that your direction reversal settings are correct ("Yes" on X and Z, "No" on Y); and that you plan to home X minus, Y plus, and Z plus.

Then you would wire your X minus switch to INP2; your Y plus switch to INP4; and your Z plus switch to INP5.

And then you would turn on (close, toggle down) the defeater DIP switches labeled "0-", "1-", and "2+" (the 1st, 3rd and 6th switches counting from the bottom of the block).

[PeteJ]

Thank you so much.

This was all part of the upgrade to the control early last year. I am trying to unravel the config that was done when I worked with support and tet it back to a more normal state.

Regarding the mill itself, it is an ATrump K4V, the goal for the limit switches is to have both the X and Y home so that the table table to the left and back as shown in the picture and z fully retracted (X-, Y+, Z,+).

If it's helpful I can post a full report in the morning once I am back in the shop.

[tblough]

Machine tool coordinate systems are based on spindle movement. Therefore X+ is actually the table moving LEFT, and Y+ is the table moving towards the operator.