New Build, Aluminium Frame Router/Mill

We have motion :)

Running a square at the limits...
https://youtu.be/tZ2FtlGJOf4

Air-cutting a 280mm circle...
https://youtu.be/fF-aAMadkAw

There is a frightening amount of power behind those axes, I tried applying some load but even with me forcing it as much as i could it made no difference :)

Then i moved on to limit switches - X first, using inductive sensors...

My brilliant idea was to use one sensor on the moving part of the axis and have two adjustable targets, all good so far;)

Got that lot fitted and set X++, X-- and X-Home all to one input (this was the smart bit I thought)

But....

The limits work but I cannot jog off of either end - it just shows "Limit switch triggered" immediately after pressing Reset, and the home works but immediately throws a limit fault after homing.

So...

Am I correct in now thinking that I am indeed a twat and you must have TWO sensors or have I missed something simple??

These sensors seem to not flip on or off - they flicker a little as the target gets near - is this normal??


Close but no cookie yet :)


Here's the rough lash-up of my panel...
Attachment 17911

Quote:

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Am I correct in now thinking that I am indeed a twat and you must have TWO sensors or have I missed something simple??

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Brill it is always good to see it move for the first time .

You only need one switch if it is traveling there is a checkbox in Mach3 so that you can jog off the limits. On the setting page I think but I would have to check

Dave go into General Config and turn off "Home With safety" then you can share the swithces for both.

Then turn on Auto limit overide and you'll be able to reset limit when triggered and jog off.

I thought that too, the only one i could see was "Home SW safety", tried that but made no difference.

These sensors seem to not flip on or off sharply - they flicker a little as the target gets near - is this normal??

Maybe the flickering is causing the issue and I've bought a load of crap sensors??

what kind of sensor.?

Quote:

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Originally Posted by JAZZCNC

what kind of sensor.?

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These ones, they seemed to be the most common type, NO, NPN.

LJ12A3-4-Z/BX

Quote:

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Originally Posted by Davek0974

These ones, they seemed to be the most common type, NO, NPN.

LJ12A3-4-Z/BX

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How are you connecting the switches to the BOB.? What pin does the Black wire go to.?

On my CP0-10V bob from CNC4YOU it goes to pin 10 and i am using input 10 in P&P settings, you can see the LED on the back of the sensor flicker as the target is starting to cover the end of the sensor, when fully covered the LED is on stable.

The sensors are powered from the 12v output on the BOB as shown in their diagrams.

The manual shows PNP swithces and your using NPN. Take 12V to pin 10 and Put Black wire to Gnd. Then it will work.

Quote:

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Originally Posted by JAZZCNC

The manual shows PNP swithces and your using NPN. Take 12V to pin 10 and Put Black wire to Gnd. Then it will work.

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This is the manual i used http://cnc4you.co.uk/resources/CP0-10V.pdf, the switches and sensors pull the pins down to activate, I guess thats active low, and i thought NPN was sink or active low output i.e the pin is pulled high internally and the sensor pulls it low?

Sorted http://machsupport.com/forum/Smileys/default/smiley.gif

These switches cannot be used for combined homing/limits - the flickering output immediately triggers a limit fault after homing as it sees the flicker as the next sense input. Probably just crap sensors.

My fix was to use them for homing only, then add soft limits to control the position limits on all axes - the mill will always be homed when in use so this seems a safe option.

However, as the sensors all use one input, it sees the flickering as the next axis sense and just zeros all the dro's - did i say these sensors are crap?

The fix - modify the home-all button script to something like this for all axes...

DoButton( 24 )
While IsMoving()
Wend
DoOEMButton(133)
While IsMoving()
Wend
Code "G53 G1 z-3 F500"
While IsMoving()
Wend

This runs the home, zero's the DRO, then steps back 3mm which is enough to get the target clear of the sensors, then it moves onto the next axis and so on. It works perfectly but does leave the tool at X3, Y3, Z-3 but then you can jog back if it matters as the soft limits will stop a crash. It does NOT work without the While IsMoving lines in there. Debounce does NOT make any difference and is now set to zero.

I guess I could add a move to zero on all axes after the homing finishes, just to park it all at zero.

A video of homing working nicely...
https://youtu.be/T2CeluqhRl4

Now i can start final wiring and finish the build, damn good fun playing with it though

Quote:

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These switches cannot be used for combined homing/limits

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I don't think it is right to condemn the switches and say they don't work for combined use. Lots of people use them it all depends how they are wired. NPN and PNP are different and have to be wired different.

Dave these switches 100% do work for both I use them all the time. It's either your using them wrong or possible the BOB doesn't work like you think.?

How you have worked around the problem may well work but I wouldn't trust for repeatabilty.

I think the answer to the problem is you'll need to use 10k resistor to force the input high.

ok, but the inputs are already pulled high internally by 4k7 so surely another pull-up would be bad??

You can see the LED on the sensor flickering unless the tip is 100% covered by the target, this does not match my previous experience of inductive sensors where they are either on or off - NO flickering!

This is not a PNP/NPN issue, these are NPN and wired for NPN normally open.

JAZZ, you use sensors, does the LED flicker?

here's a video...
https://youtu.be/S5PP5sQh5Vk

Quote:

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Originally Posted by Clive S

I don't think it is right to condemn the switches and say they don't work for combined use. Lots of people use them it all depends how they are wired. NPN and PNP are different and have to be wired different.

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I didn't mean "these" as in all sensors, just maybe these super cheap eBay ones possibly, they were only £2.50ea. Previous experience was that the LED & output was either ON or OFF, not flickering depending on how close the target is.

Even the super cheap Ebay ones work ok dave.

You haven't wired the switch powers in series have you.? That flickering looks like struggling for volts.!

Quote:

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Originally Posted by JAZZCNC

Even the super cheap Ebay ones work ok dave.

You haven't wired the switch powers in series have you.? That flickering looks like struggling for volts.!

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Hi

No, all wired in parallel as described in manual, I have a quality bench psu and will test them on that now...

If you fully cover the end with the target the LED is solid on, but mach picks up the very first flicker and takes that as the position, as expected.

Maybe these are fakes or junk clones which have the output conditioning circuit missing??

Nah I'd be suspecting the conflict between swithc and BOB my self. The input isn't conditioned correctly. Stick a 10K resistor on between 12v and pin 10.
Worst case is it will slow down the input reaction time.

I've had this before with prox switches and PMDX board using ESS.

Thanks Jazz, I have some updates..

This seems to be a PSU issue believe it or not!

The BOB is powered from a little 15v SMPS, the sensors are powered from the BOB which has a DC-DC converter and puts out 12v.

First test was to put a sensor on my variable bench PSU, they worked perfectly! Clean on and off LED - perfect.

So i tried running the sensors direct from the 15v PSU - these are NPN so supply voltage does not affect the output signal and the 0v in/out is common on the BOB - result was that it worked ok UNTIL I took Mach out of reset when the flickering returned - baffled!

Next i tried running the BOB from the bench PSU - perfect result and i could even enable the limits (on one axis anyway) and it all worked as I first expected it should.

So - do we have a duff PSU, are these sensors sensitive to SMPS output?
I am not sure what to try now - baffled.

Maybe add some uF to the output of the supply and maybe some filtering?
I might get the 'scope out and see whats on the supply.

Get a different PSU? (this one came from CNC4YOU as did the BOB)

Here's another oddity - the plasma always wipes out the radio as soon as the drives are enabled, now it seems this build does the same - as soon as the drives kick in, the radio gets washed out.

Both builds use SMPS and all parts came from CNC4YOU. Food for thought.

Quote:

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Originally Posted by Davek0974

I didn't mean "these" as in all sensors, just maybe these super cheap eBay ones possibly, they were only £2.50ea. Previous experience was that the LED & output was either ON or OFF, not flickering depending on how close the target is.

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You got robbed you can buy them for about £1.30 on ebay. I think you might be correct with the pull ups in that case I think you will need PNP sensors. But that doesn't mean they are crap.

Quote:

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Originally Posted by Davek0974

Here's another oddity - the plasma always wipes out the radio as soon as the drives are enabled, now it seems this build does the same - as soon as the drives kick in, the radio gets washed out.

Both builds use SMPS and all parts came from CNC4YOU. Food for thought.

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Hence why I won't use SMPS(switch mode power supply for those wondering.!) on any drives. The fact you have probelms with one on the BOB doesn't inspire confidense in the BOB for me. It's needs should be simple and only be pulling milli amps so not taxng to any psu.!

Quote:

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Originally Posted by Davek0974

So - do we have a duff PSU, are these sensors sensitive to SMPS output?
I am not sure what to try now - baffled.

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To answer this question then NO they usually work fine with SMPS. That's what I use for 24v circuit. Try a different PSU

I need to narrow things down a little - is it the drive PSU upsetting the BOB or is it the BOB PSU ?

The BOB pulls 150mA including the three sensors.

Will be back soon with some results, the BIG worrying me is the radio interference - the plasma is fully grounded etc and works perfectly BUT it pumps out RF like billy!

Maybe I need to ditch the SMPS's and go linear.

Off for some tests.....

Hi Dave,

Going back to your first motion videos it looks like the X bearings could come off the ends of the rail as there is no hard end stop. Does something on the ballscrew contact first to prevent this?

Quote:

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Originally Posted by routercnc

Hi Dave,

Going back to your first motion videos it looks like the X bearings could come off the ends of the rail as there is no hard end stop. Does something on the ballscrew contact first to prevent this?

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Hi, yes at present they can easily come off, and have done ;)
No balls were lost though, luckily.

Well, I am just about ready to give up for the day! And I hate shutting up shop on a negative position. :(

It works fine if i run off the variable bench PSU but not on the little SMPS, but i don't think it's needed to spend £110 on a PSU just for the BOB!

Here's a video showing the result on the SMPS...
https://youtu.be/m9_6XrzW0Fc

And here's one showing what I expected and indeed what I get on the bench PSU...
https://youtu.be/XcI2J5RcyrE

Now the big question is WHAT DO I DO??

Obviously I will be throwing this at CNC4YOU as it's all their components but they usually blame the setup or the earthing or the wiring blah, blah, blah...

Facts...

The drive PSU & drives wipe out FM radio when engaged.
The BOB PSU does not work with my sensors.
The sensors appear fine when on a different PSU.
I am a bit p1ssed off at present as this little setup should have been easy ;)

Just about ready to pour a big one.

Well look at it has good result it's just not the one you wanted.!! . . Good because you know the cause and not ending not knowing the reason.

The fact the bob works with bench supply shows it's working so PSU would be my first choice.

The drives affecting radio is a little concerning because shows dirty system (or Crap drives) so i'd be looking at this while i'm at it. Personanly it's no brainer to me I'd dump the SMPS and go with toroidal setup. 15mins work to man of your calibre.!!

Thanks Jazz,

Is there a preferred circuit or supplier of parts for a suitable linear supply?
Need 48v at up to 10A.

Keep the BOB on the SMPS?

The radio interference has been nagging me since i got the plasma going - same drives, motors and PSU again, no help at all from CNC4YOU of course.

I always use shielded motor cables, grounded at the drive end, and even used shielded wire for the step/dir signals on the plasma.

No objections to building a psu but cant risk over-volting the drives by building it wrong, they are ok up to 50v

Thanks

Plasma by it's nature is dirty business so no surprise when that fires up but drives them selfs shouldn't be messing with radio.

So many things could be in play here like you know but I'd certainly start by getting rid of the SMPS for the drives. Nothing to them really just toroidal transformer Caps and bridge rectifier.

Size wise then it gets tricky with 50v because standard transformers either compute very close to 50vdc or just a little lower than needed.
The transformer I would use is this one with 2 x 33Vac secondery's giving 300va because. While it's less than 48vdc it's safer than next option which would close to 50vdc.

Normally I'd wire secondery coils in series which adds the volts together but keeps the amps same and use lower voltage seconderys. But in this case the nearist available which is 2 x 15Vac computes to low Ending up around 40Vdc after being recified.
Next option is 2 x 18Vac which takes too close to 50vdc.

So in this case going with 2 x 33Vac and wiring in parallel will give around 44Vdc and add the amps together giving 9A. This is much safer option and won't cost any performance. The way Toridal works then 9A is more than enough for 4 drives.

This one.
http://www.airlinktransformers.com/c...nge/CM0300233/

Then you'll need 3 x Caps around 4700uf 63v wired in parallel these will do nicely
http://www.ebay.co.uk/itm/4700uF-63V...-/111907866124

Then 25A bridge and your sorted.
http://www.ebay.co.uk/itm/KBPC2502-2...oAAOSwDk5T7ghA

Thanks Jazz,

I was leaning towards 30v secondary but that one does fit well, have got caps and bridge so the transformer is on order now.

If that works I'll ditch the PSU in the plasma too - note that it's not the PLASMA that kills the radio, it's the CNC drives again, as soon as i take Mach out of reset.

Hopefully this will move us along again, fingers crossed.

Had a reply from CNC4YOU, they have tested all their stock of the SMPS i have and found 1 that has the same issue - at least I am not going mad.

They are sending out a replacement unit, 24v this time.

I have also borrowed enough bits to cobble together a 36v linear supply, if the new SMPS fails to sort the issue, I have that option ready to try.

Also ordered parts to make a full-power linear supply.

The radio interference is a false lead i think - i borrowed a FM/DAB portable last night and the signal is so weak in the shop that DAB was 100% dead and FM only just worked on Radio2 (which is all i use really, never bothered trying other stations so did not notice the massive lack of signal) So it may possibly be just caused by a very weak reception area. I'm ignoring this issue for now.

Well, I'm officially baffled but very happy!

Changing the BOB PSU has completely fixed the issue, I have now got sensible homing routine, all limits working and the homing accuracy is now better than 0.1mm, more like 0.00 to -0.06mm variation over 25 homing calls.

Happy days :)

Now, the question is,,,,

Having bought all the parts to make a linear PSU, is it worth fitting it or should I leave it as-is??

Quote:

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Originally Posted by Davek0974

Now, the question is,,,,

Having bought all the parts to make a linear PSU, is it worth fitting it or should I leave it as-is??

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If it aint broke don't mess. Just keep it on stand by.!

Out of interest have you tried this on Plasma to see if it stops that.?

No, i'm not tempting fate, don't want to risk upsetting her ;)

Things are progressing...

Attachment 17959

Leaving it on the little bench i made to build it, fits well and the electrics will fit underneath nicely.

Since the picture was taken I have fully wired the panel and tested the safety circuit etc, this is now in the cabinet and waiting connection. The VFD is mounted behind the cabinet so i can see it from under the table, this keeps it safe from flying chips etc and away from the drive electronics.

I have the E-stop circuit controlling the VFD and cooling pump supplies, it also has a connection to the BOB to tell Mach3 that it's in E-Stop, this circuit also functions as a No-Volt-Release system to stop the spindle restarting after a power loss.

The pump supply and misting system solenoid is controlled from a relay board driven by the VFD internal relay so they come on and off as the VFD does, the misting supply also has a front panel switch so i can leave it off when cutting wood etc.

Tomorrow will be wiring, testing and making the bed and fitting it hopefully.

:subdued:

Well, she survived the rewire and panel fitting, also got the VFD fitted and spindle running under 0-10v and stop/start from the BOB. Surprised how quiet the motor is.

Installed the new screen-set (2010) and got that going, looks nice. Tweaked the homing speed and at 15% the homing accuracy is now +0 to -0.02mm which is far better and will leave it there for now.

Questions ---

Touch plate -
to make this work i need to connect the probe input to ground via my tool, I presume it is OK to connect the BOB 0v line to machine chassis in order to make this work with only one probe wire??

Spinde Stop -
Do we use coast-to-stop or ramp-to-stop??

Spindle acceleration -
What sort of spin-up setting is good in the VFD?
I presume this also goes in Mach3 Spindle delays?

Got to finish my bed plate now...

Thats enough for one day ;)

Got the main bed plate on, aluminium top-bed needs to be drilled and tapped for hold-downs etc, thats tomorrows job.

Attachment 17967

Coming along :)

Coming along nice Dave.:thumsup:

Quote:

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Originally Posted by Davek0974

Touch plate -
to make this work i need to connect the probe input to ground via my tool, I presume it is OK to connect the BOB 0v line to machine chassis in order to make this work with only one probe wire??

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Yes can do it that way thou need to be careful and check the probe by touching tool every time just in case tool doesn't conduct very well ie: coated etc.
IT's good habbit to get into.

Quote:

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Originally Posted by Davek0974

Spinde Stop -
Do we use coast-to-stop or ramp-to-stop??

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Little bit of DC braking won't hurt but not too much else trip VFD with large tools.

Quote:

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Originally Posted by Davek0974

Spindle acceleration -
What sort of spin-up setting is good in the VFD?
I presume this also goes in Mach3 Spindle delays?

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I have mine set to 2 or 3 secs and spindle delay set to 2. Again if spindle startup too fast you'll get vfd throwing up error codes.
Mach delay needs to be about the same delay.

Thanks Jazz,

Will set those tomorrow.

I might have to re-visit my linear rail parallel setting - something appears to have moved slightly during build as the top-right corner of my bed seems about 0.3mm high compared to the other three which are relatively true. As you can see in the pic, I have mounted a DTI on my spindle clamp and was measuring the bed while jogging around.

Its a bit of a pain as it means almost full strip-down, not sure i can shim the bed that much to get it happy, will have another look tomorrow.