Help please. Dip switches and mach 3 settings

[Radu_Andrei]

*once you crush the end it is f***ed (rendered inoperative permanently)* - the switch or the cnc?

[Radu_Andrei]

Hi again.
Shortly after the the 3 weeks old conversation, I received 3 inductive switches, which I.ll install next week.
I like Rob.s approach of also keeping some mechanical switches in place next to the homing ones, but I.m somewhat unsure what.s the best way to wire all this.
I.ve only got 5 pins on the Bob, one being used for the probe. So 4 pins for the remaining Estop, 6 mechanical limit switches (2 for each axis), 3 inductive homing switches (3wires).

So for example (let.s say P15 is the probe)
1. Combine all limits and estop in let.s say P10 and have P11,12,13 for x,y,z home switches.
2. Combine all limits in P10 and all homes in P11, Estop in either P12 or 13
3. Combine the limits and home of each axis in one pin

So what the best wiring option and why?

[cropwell]

First , what inductive switches have you got? Keep Estop separate! All your limit switches can go in series to one pin using Com and NC on the switch, then you can put a push-to-make switch across the lot so you can jog off your limits when you hit them (otherwise you have to toggle and jog, then toggle again) . All your homes can go to one pin using diode routing if needed.
So I have just described option 2.

Homing works by moving an axis to trigger the home switch and then backing off to where the switch is not triggered, so it it quite OK to use the same i/o pin.

[paulus.v]

Hi again.
Shortly after the the 3 weeks old conversation, I received 3 inductive switches, which I.ll install next week.
I like Rob.s approach of also keeping some mechanical switches in place next to the homing ones, but I.m somewhat unsure what.s the best way to wire all this.
I.ve only got 5 pins on the Bob, one being used for the probe. So 4 pins for the remaining Estop, 6 mechanical limit switches (2 for each axis), 3 inductive homing switches (3wires).

So for example (let.s say P15 is the probe)
1. Combine all limits and estop in let.s say P10 and have P11,12,13 for x,y,z home switches.
2. Combine all limits in P10 and all homes in P11, Estop in either P12 or 13
3. Combine the limits and home of each axis in one pin

So what the best wiring option and why?

I have all the limit switches and estop wired in series (NC) to the main contactor that powers everything except the breakout board. One signal wire goes through a spare contact of the contactor to the breakout board to tell mach3 to stop the g-code.

The homing sensors are connected to the same BoB input in parallel as I don't use simultaneous axis homing but need the spare inputs (actually I use one more input on X as I have dual motors and need to square the gantry). The homing sensors are configured as home and limit in mach3.

In 5 years I've never hit the limit switches one single time as the sensors are working as limits as well and never failed.

[Radu_Andrei]

Thanks for the reply.
I don.t get why is the contactor involved in all of this. When you interrupt the signal wire (open the contactor), you also kill power to everything else, except the BoB. Why? Why not use just Bob input terminals?

Could you please post a picture with your limits and homes setup? If not to much trouble even with the whole cnc machine. It never hurts to see a new approach.

[Radu_Andrei]

Another thing that gives me a hard time, is that I have some ballscrew whip. It.s 20mm dia, and 1500mm long, one fixed and on simple end support. On the y axis, on the last 300-400 mm moving towards the stepper, I get some whip. At 3000 mm per min (118inch per min) it.s quite strong. Reducing the speed to 2200 (86) it is very little. I assume lowering to 2000 (78) will kind of fix it. I would prefer 100 ipm.

I found two ways of fixing that online. One is a spring support at the middle of the screw, that reduces somewhat the whip, the second is a change in design to make the ballscrew stationary, and rotate the nut (A LOT OF WORK TO CONVERT TO THAT).

Has anyone encountered this kind of problems, and what solution did you come up with?

P.S. Regarding the pictures with the cnc machine from post 204, please feel free everyone to post some photos with your cnc routers, especially those which used them for some time, as I.m sure you.ve updated your machine design to solve all or most of the problems. This includes you too, Rob. :) You.ve posted a photo with your beautiful limit switches, but I did not have the honour to see the entire cnc, and as you always seem satisfied with its performance, it is of paramount importance to my existence to see your cnc rounter. :)

[cropwell]

Regarding the pictures with the cnc machine from post 204, please feel free everyone to post some photos with your cnc routers, especially those which used them for some time, as I.m sure you.ve updated your machine design to solve all or most of the problems. This includes you too, Rob. :) You.ve posted a photo with your beautiful limit switches, but I did not have the honour to see the entire cnc, and as you always seem satisfied with its performance, it is of paramount importance to my existence to see your cnc rounter. :)

Don't think for one second, that I am satisfied with my machine. It is very 'entry level' A4 machining area, Unsupported rails, trapezoidal screws and delrin nuts but its' most damning feature is that it was made by MD. I have done what I can to stiffen up where possible without major rebuild. If you go carefully with it, you can get OK results.

As far as the inductive proximity sensors is concerned you need at least 12v, preferably more, for them to work reliably.

[Radu_Andrei]

Paulus v.
As I said it.s 3-4 meters away from the workshop. My newly built house it.s like 10 meters away. The construction authorization was released by the owner of the towers, in this case Enel, and the City Hall. If I remember right, the minimum distance required was 7 meters. I did not bribe anyone. It is just the way it is. I do not hear any hum, but I.m quite sure they work all the time. I am not sure, if the are high or medium voltage power lines. My cnc works fine now after fixing the grounding. There is still room for improvement though.

As for the health issues, this electrical tower is here since my grandfather was young, and no one in the family had any serious health problems, and counting aunts, uncles and cousins, it is a big family.
There are people here alive which worked in the uranium mine, and they are alive today, and hardworking strong aparently healthy men that died of cancer. You have 60 years old smokers that do just fine, and 3 years old with leukemia. So, excuse my scepticism toward the recomendation of the experts, but they miss something. I am NOT saying that care and resposability are of no use. In fact they are great and make your life a lot better, but I would love to see for once, attached to a claim (regarding anything, health, nutrition, cancer, electromagnetic radiation etc) to see the study behind it, and I mean place, date, names of the people involved, telephones, emails, experiments, conclusions, reports etc. This is not a reply pointed at you, it is just about a principle. The scientific method principle. First let.s prove it, and then share it. :)

Sorry for the long reply. A couple of years ago, I did a personal study about nutrition and health, mainly about what foods should you eat, why, in what quantities, and listening and reading all the sides involved in the debate, these including vegans, vegetarians, frutarians, raw eaters, only meat, no meat, no grains, no eggs, no legumes etc, It lasted a few months and in the end, I guess the only safe way is to go out and chew grass, or eat nothing. Very little studies existed for all this claims. Anyway, if my health goes bad anytime in the future, I will keep you posted. :)


Rob.
An MDF, A4 machining area, Unsupported rails, trapezoidal screws and delrin nuts machine that works, it.s better that a fancy one that does not. And better than all is the attitude. I honestly though you have a high end hiwin rails, high pitch ballscrew, or tensioned double pinion and rack, 2.2 kw water cooled spindle, aluminium extrusion frame, vacuum table machine. All the bells and whistles. Perhaps more than a better machine, I need a better attitude towards it.

I just finished this evening installing the homes, and they seems to work just fine with 12v supply. I will however post a video these days, with the aparently last problem :)) (I know, don.t laugh), of the y axis wobble, or whip, I am not sure yet, maybe you see something I don.t. It.s not that bad and it is manifesting a bit strong only on 10-20 cm of travel.

My little mistake, is that seduced by the almost great functioning of the machine, I did a few works and sold some, and now the interest is quite big, especially for religious carvings, and I get a bit of pressure from the people in the area, and I cannot deliver. Not yet. Until I figure out if this whip is something that can ruin a ballscrew very quickly or it is not a big deal. 20mm 5mm pitch, one fixed one free end, 1500mm (4.92ft) long. We shall see.

[paulus.v]

Thanks for the reply.
I don.t get why is the contactor involved in all of this. When you interrupt the signal wire (open the contactor), you also kill power to everything else, except the BoB. Why? Why not use just Bob input terminals?

The BoB input alone is not reliable enough to be used for an emergency stop.

Estop, the emergency stop, that big red mushroom button should be there for emergencies. Water is leaking through the motor electrical connections and on the floor so you could be electrocuted or something in the machine catches fire ... You will be hitting the Estop while running for the door or the fire extinguisher. In those cases you want to kill all power to the machine with that button.
The reason I've put the limit switches on the same loop with the Estop is that I have the sensors for the limit. If the sensor is not stopping the axis, then something should be really bad with mach3 or the motor drive and I want the end switch to stop everything before hitting the end of axis travel.

For minor "emergencies" like loosening the workpiece or hitting a clamp you have the mach3 Stop or Feed Hold buttons.

[Radu_Andrei]

Hi Paulus.v
I also have an emergency estop which cuts power to everything, except the pc and the BoB, but I have never used it. (this being the hardware stop). I did, however used the software estop (input terminals on BoB) a few times, when I messed up gcode programing, and it worked quite well.
Your representation of the work conditions in which the cnc will function are a bit dramatic for a work shop, as I.m quite sure it is not positioned under a waterfall, but as I cannot help notice the flag situated at the left side of your user name it.s quite similar with mine, I think such a Estop described by you, should be very helpful if assigned to our prime minister, leading party and most of the political machine that is running our country. :) Best whishes, and happy national day for 01.12.2018! :)