Homing switches issues!

[setcon]

Good day,

I am new to CNC though I do work in a Tool Room with 2 other guys who run the CNC's in the workshop. So I work with Lathes, Mills, etc and I have been designing parts on Solid Works since early 2015. I am asking them for assistance to learn everything required so that isn't an issue. There is something they cannot help me out with.

So I have been quite busy but I have assembled my M3 CNC kit and made a temporary fix for the power supply for the spindle (I have designed a container which I will 3D Print at a later stage). I haven't done anything besides assemble. Connect it to my PC and attempt to home. Now knowing that if the homing switches don't work I haven't done a homing cycle and all I have done is unlock the movement on the XYZ using "#x". I have then moved the Z axis up and down not holding the switch in then holding the switch in. Regardless it will still move up and down which I believe is incorrect. I have used a multi meter to measure the output from the switch itself and then also measuring the output on the connectors which connect to the PC board.

I would like you to please take a look at the images/videos in my Dropbox folder and see if I am making a noob mistake or is there actually something wrong with the PC board?

(https://www.dropbox.com/sh/v7rttbihil9ot63/AAB_-bNR2n0vhZWingeefSHMa?dl=0)

I have marked each cable to ensure that I am placing the correct one in the correct place on the PC board.

[aforww]

Good day,

I am new to CNC though I do work in a Tool Room with 2 other guys who run the CNC's in the workshop. So I work with Lathes, Mills, etc and I have been designing parts on Solid Works since early 2015. I am asking them for assistance to learn everything required so that isn't an issue. There is something they cannot help me out with.

So I have been quite busy but I have assembled my M3 CNC kit and made a temporary fix for the power supply for the spindle (I have designed a container which I will 3D Print at a later stage). I haven't done anything besides assemble. Connect it to my PC and attempt to home. Now knowing that if the homing switches don't work I haven't done a homing cycle and all I have done is unlock the movement on the XYZ using "#x". I have then moved the Z axis up and down not holding the switch in then holding the switch in. Regardless it will still move up and down which I believe is incorrect. I have used a multi meter to measure the output from the switch itself and then also measuring the output on the connectors which connect to the PC board.

I would like you to please take a look at the images/videos in my Dropbox folder and see if I am making a noob mistake or is there actually something wrong with the PC board?

(https://www.dropbox.com/sh/v7rttbihil9ot63/AAB_-bNR2n0vhZWingeefSHMa?dl=0)

I have marked each cable to ensure that I am placing the correct one in the correct place on the PC board.

The homing switches do not act like limit switches unless you have that option configured in your GRBL settings. $20=1 to activate soft limits. If it is $20=0, the homing switches will only work during the homing cycle and will then be ignored afterward. I strongly suggest you read up and experiment with soft limits before you use them during an operation. Soft limits will not only cause the homing switches to kill the movement, but they will also kill movement once your machine hits the maximum travel distance. This keeps you from crashing the machine but will require you to shut down UGS and restart it to clear the lockout. 

[setcon]

Well I decided to run a homing sequence. Though I made sure the Mrs was around to help. I asked her to press the switch in after I ran the homing process. Lets just say I had to power down because it didnt back off but I did make sure to not let it reach max.

[Derek the Admin]

Hey... some clarifications to what Aforww said. It's HARD limits that respond to a switch hit outside of a homing cycle. The soft limits just look at the position and determine if a command exceeds the programmed "software limited" range.

We don't enable hard limits because even with the filtering capacitors soldered on you are prone to false triggers because a small milling machine is a storm of electrical noise. Most people, including some competitors, leave hard limits disabled for this reason.

[Derek the Admin]

I think I see your exact problem. I see you have a laser. Using the laser requires a pin reassignment by reflashing to another version of the firmware.

Essentially, the spindle enable (probably labeled "Sp En") and Z homing pins get swapped in that version of the firmware to allow for the laser to be controlled by a pulse width modulation feature that is only present on that "Z limit" pin, hence the reassignment.

I am not sure if you reflashed the board based on instructions you read for laser setup or if your distributor reflashed the board prior to sending it to you, knowing that you have a laser. If it has been reflashed to the laser firmware (which, again, will be required for laser operations) then the Z switch must be plugged into at spindle enable pin that is a few spots below on the board. Again, it's probably labeled "Sp En" or something similar.

If that is not it, I would highly recommend checking the crimps on the wire to ensure you have a firm connection.

I think moving it to that other pin will fix this, however.

Derek

[aforww]

Mar 15, 2017 17:24:27 GMT Derek the Admin said:

I think I see your exact problem. I see you have a laser. Using the laser requires a pin reassignment by reflashing to another version of the firmware.

Essentially, the spindle enable (probably labeled "Sp En") and Z homing pins get swapped in that version of the firmware to allow for the laser to be controlled by a pulse width modulation feature that is only present on that "Z limit" pin, hence the reassignment.

I am not sure if you reflashed the board based on instructions you read for laser setup or if your distributor reflashed the board prior to sending it to you, knowing that you have a laser. If it has been reflashed to the laser firmware (which, again, will be required for laser operations) then the Z switch must be plugged into at spindle enable pin that is a few spots below on the board. Again, it's probably labeled "Sp En" or something similar.

If that is not it, I would highly recommend checking the crimps on the wire to ensure you have a firm connection.

I think moving it to that other pin will fix this, however.

Derek

I wasn't aware of the hard limits. That's odd because I don't​ have hard limits activated but I do have soft limits on. As soon as it hits the switch it stops it. Guess that's more the location of switch activation opposed to the actual triggering of the switch.