Some of these proximity switches already have a pull-up resistor inside.
Here is a good explanation of how to calculate it's value.
See page 11 http://cnc4pc.com/Tech_Docs/C50R1_user_manual.pdf in the ones I have it is 10K
..Clive
Printable View
Some of these proximity switches already have a pull-up resistor inside.
Here is a good explanation of how to calculate it's value.
See page 11 http://cnc4pc.com/Tech_Docs/C50R1_user_manual.pdf in the ones I have it is 10K
..Clive
Hi Graeme, HankMcSpank,
OK, that makes a bit more sense now, thank you. I'll check Hank's suggestion first - power it up without the resistor between black and brown and check the voltage on the black. If it is nothing then I have a simple switch and can follow up on your suggestions Graeme. I may need to clarify something with you but lets see what I have first.
If it is 24V then I have a pull-resistor inside the sensor and need to do something else as I know this board won't like 24V into the logic circuits!
I see Clive has posted as well so I'll have a read of his link next . . .
Thank you
If there is a voltage on the black, then a simple voltage divider should do....but it'd be useful for you to measure the input resistance of the follow on BOB board input pin (as that will end up being in parallel with your proposed voltage divider)....I'd imagine it'll be very high input resistance on your BOB input.
Checked the black wire without resistor and it was 12V (running from 12V supply for now) which means there is a resistor in the sensor and I can't wire it as a simple switch. Used method Clive posted and worked out the value as around 5k ohmQuote:
Originally Posted by HankMcSpank
So I can work out the other resistor required to complete the divider except I need to factor in the Bob resistor
Tried to check Bob resistance across pins with multimeter (board was off) and got no reading at all. What is the method to determine this resistance
As mentioned, the BOB input resistance will likely be high ...there's nothing special involved with the measuring method - just check for resistance between the BOB input pin & BOB ground ...powered off is fine. (if you get too high a reading for your meter to detect, then to all intents & purposes the BOB input resistance can be disregarded for the purposes of your 'to be deployed' voltage divider)Quote:
Originally Posted by routercnc
What supply voltage do you eventually intend running your sensor with?
I had the meter on max setting and still got no reading
Final system will be 24V when PSU arrives - testing on 12V for now
OK
If the internal R is 5K then the most current that can flow at 12 V will be 2.4mA. Just to prove this put the meter in series with the black wire to gnd and check (put the meter on to the mA range). I am sure that I used one of these sensors connected to the 5V input of my bob. But don't let the magic smoke out. ..Clive
I was just about to suggest trying to establish what value the internal R is (on the sensor)....try connecting a 4.7k resistor between your sensor's black wire & your supply voltage ground ...power up the sensor & measure what voltage you have across the 4.7K resistor (it doesn't have to be a 4.7k resistor ...whatever resistor you have to hand!)
Small update. Thanks for all your help on the proximity switches. I think I have a plan on that now but will revisit that later because . . .
24V PSU, 2off 24V relays, and the 20A contactor all arrived in the post today! Big thanks to Dean for some behind the scenes help :wink:.
Managed to get a quick hour in the garage tonight and made some progress:
24V PSU wired in
Contactor to control the linear power supply mostly wired in (need the 24V DC feed to complete)
Shifted all the earth blocks to a common location to make proper star-earth point
Made new earth cables to suit
Added terminal end block clamps to stop them wobbling around
Swapped out one of the 12V relays for the new 24V, but not wired in. Got one more to do.
Added 2 pairs of green adapter brackets (near the VFD) - these will guide the power and signal cable (not added yet). Not really required but they were about £1.30 for 2 on ebay and I just liked the look of them !
Overview:
Attachment 15436
AC DIN rail coming along:
Attachment 15437
DC DIN rail getting close (ignore 12V labels it will be 24V):
Attachment 15438
Questions on the contactor:
T1, T2 are the mains input ?
L1, L2 are the switched output ?
Should I keep the earth permanently connected (i.e. not through T3/L3 of contactor) ?
A1 / A2 24V DC polarity important? I'm guessing not.
There is a 0 / 1 switch in the middle - some sort of tester / over-ride? Can I leave it at 0 ?
Yes Either or doesn't matter really it's just a switch.Quote:
Originally Posted by routercnc
Yes leave Earth unbroken.Quote:
Originally Posted by routercnc
Yes it matters. A1 is Positive A2 Negative.Quote:
Originally Posted by routercnc
It's not a switch it's a Lever. The Contactor can have a Module added onto front and this switches it. Look inside the Box it came in and you'll see what i mean.?Quote:
Originally Posted by routercnc
It's a very neat and tidy job you are doing:thumsup:.Quote:
routercnc
.
May I ask where you got the three blue connectors (on the din rail next to the relay) from?.
.
Can I see a blue wire trapped under the din rail where the connectors are!! ..Clive
Dean
Thanks for the info. Rushed out into the garage and didn't really see the printing inside the box!
Clive
Thanks for the encouragement!
blue terminal blocks were from ebay
http://m.ebay.co.uk/itm/331547573505?nav=SEARCH
They are really for mains neutrals but work ok like this
Had another look at the picture and it does look like a wire is trapped but it must be a bit of outer sleeving that has dropped into the rail. I was stripping a lot of cables last night.
Bloody hell Clive you must have eaten some carrots as a Kid. Had to look really hard to see that even after you highlighted.:black_eyed:Quote:
Originally Posted by Clive S
That's what happens when you won't go to bed early.:fatigue:Quote:
Originally Posted by JAZZCNC
Got the 24V relay and the contactor wired in earlier this week. But when I energise the 24V relay, the contactor switches but the MCB for the linear supply then trips out. Tried it twice and it tripped both times.
.
Wiring diagram re-posted here:
Attachment 15450
.
Here is a close up picture if it helps:
Attachment 15451
.
The powering up sequence is:
1. Plug in and switch on at wall - this powers up the 24V PSU
2. Switch master on/off switch which puts the system into e-stop mode and lights up the red LED
3. Press the RESET momentary button which switches off the red LED
4. This energises the 24V master relay (which self-latches)
5. The master relay makes a circuit which runs 24V to the contactor A1/A2
6. The contactor switches on (with a click, and the lever indicator on the front moves to I)
7. This takes the mains power from the 6A type D MCB . . .
8. . . . and feeds it to the linear PSU (which is connected to 3 drives), but the MCB immediately trips
.
If I disconnect the linear PSU then the relay, MCB and contactor operate and power up correctly and stay on so it would seem that the transformer inrush is too high for the MCB?
.
Previously with the linear supply connected to one driver and just through the MCB without the contactor it has switched on (on the one and only time I tried it) without a problem.
.
So, what to try? - What is the reason for most of the current draw ? -
Inrush through the 'shorted' coil until the magnetic field is established ? (750VA 2x24)
Charging up the capacitors (40,000uF) ?
Doing the above and powering up the 3off DQ860MA 80V drivers ?
Or some from each ?
.
I could try switching on and off several times without any drive connected
I could then try disconnecting the AC supply to the rectifier and see if the MCB stays on with just the inrush through the coil - is that OK to do?
If that is OK I could unsolder one of the capacitors to reduce the charging draw.
Up-spec the MCB ?
.
Any ideas? thanks
EDIT:
Bit of reading around and found a document from Allen Bradley, who make lots of good control gear. As I'm protecting the secondary with fuses I can go a bit higher on the primary protection as it is 'just' protecting the wire to the coil and the coil itself. So can probably go to 10A - my logic being:
10A type D should offer around 200A peak for a couple of cycles during switch on
During normal use I'm expecting a couple of amps, so will be OK there
If there is a problem on the primary the 10A MCB should go first as the coil can take 15A and the wall fuse is 13A
Chalon sell the double pole 10A type D for £10.25 all in . . !
Worth a try?
Exactly What I was going to suggest. I think you'll find that you can even get away with 10A Type C. It's worked for me many times before just to get going so try this if you have one.!Quote:
Originally Posted by routercnc
Now if you make a soft start for the PSU and i will officially say you are the master of enclosures :applouse:
http://www.ebay.co.uk/itm/220V-Class...item3f3f435e81
http://electronics-diy.com/soft-star...wer-supply.php
Thanks Dean
OK will get my order in with Chalon . . .
Silyavski
Wow, wouldn't say I'm the master of enclosures - I'm making most of it up as I go along!
Looked at soft start options but I only found home made circuits so thanks for those links. Hope to get away without them but good to know there is a ready made module should I need it
Good news !
10A MCB type D arrived today so I swapped out the 6A unit, held my breath, and switched it on. The contactor clicked and the drivers powered up !
.
Could have been lucky (by chanced switched at maximum peak voltage) so tried it again. Same thing, worked fine. Switched off and tried one more time. All fine again. All this was with 3 drivers connected (but no motors yet).
.
Switched off again and checked the decay time on the linear supply and it dropped from 72V at just over 1V per second, and stopped at around 3V.
.
Here is the proof:
Attachment 15498
.
And here is the new unit (the one on the right):
Attachment 15499
.
It will be the weekend at the earliest now but hope to mount it on the wall and plug in all the cables etc. to get the basic machine running. It might be the following weekend but hope to machine out the control panel that I was cutting out when it went bang last time.
.
Purely for neatness a few days ago I ordered another DQ860MA 80V stepper driver for the Z axis. When it arrives this means all 4 drivers can run from the single linear supply (I sized it at 750VA to cope), and I can get rid of the 32V SMPS in the top corner. The Z axis stepper is 1.8Nm and only around 1.7mH so I think I need to wire it in series to keep the current down.
.
I also ordered a small 5V SMPS so I don't need to take a feed from the PC molex power supply. Just feels better this way. The top of the control box will then be shuffled around a bit to get a really nice layout and it will allow me to seperate the power and signals even more than current.
Coming along nice Barry hopefully no more troubles.!
I thought I wait for decent progress before posting again.
Finally mounted it to the wall and wired in the stepper motors. At 72V it jogs around much faster than the previous machine!
Attachment 15643
The monitor will mount to the door, probably on a small pivoting bracket.
I've swapped out the Z axis stepper driver to another DQ860MA and am running it off the main linear power supply. This meant I could remove the 34V SMPS power supply. I've also added a 5V PSU to run the breakout board (next to the invertor).
Attachment 15644
I decided after much thought to put both X axis stepper drivers on the same fuse and up the rating to 10A (Y and Z are on 5A each). I was worried that if one fuse blew the gantry would quickly twist and do some damage. This way if one goes they both stop. What has everyone else done?
Recently I managed to machine the front panel and offer it up as a trial. Fits OK but was a pain to machine. It is 3mm aluminium 1050 grade which is very soft. Didn't help that I'd not paid much attention to the 6mm bit I ordered recently and it arrived with 3 flutes. In the end I had to machine it very slowly (120mm/min at 1mm DOC) otherwise it stuck to the cutter.
Attachment 15645
It should look like this when finished:
Attachment 15646
Still need to wiring up all the buttons to the panel, add the POKEYs board to the back, wire in the external e-stop, the machine limits and proximity home switches . . . . .
Can't come soon enough to be honest as I managed to jog the machine into the (non-functioning) micro-switches on the X axis and smash them to pieces, plus bend the end stops a bit. Those motors have some power now on 72V !
Another problem is this afternoon the PC just switched off without warning (wasn't cutting just doing a bit of CAM). When I switched it on it said there was a keyboard error and would not start !! More to sort out - but it will have to wait for my next session.
The PC switch-off turned out to be overheating. At least that is all I can think of as it had been on all afternoon machining and it was a very hot day. It's working fine now.
Attachment 15669
I've fitted all of the buttons and started to wire some of it up. Power on/off, e-stop and reset, auxillary to run cooling pump and fan, and spindle start/stop all work. In the process of wiring up the spindle speed through the 10K pot. I'm hoping to get the readout to show the rpm.
Cycle controls and feedrate are not functioning yet. I've still got the POKEYs board to fit and wire up to get those going.
All the e-stop interlock functionality works (e.g. can't start spindle until e-stop is reset, and pressing e-stop stops drivers and spindle), but I've noticed that if the VFD is off at the mains and you switch on the control system, reset the e-stop to get the drivers on, and press the spindle start button on the new control panel, and then switch the VFD on at the mains the spindle starts straight away. It might be possible to add a further interlock for the spindle start/stop if the VFD is not on but as I can't reach the mains socket and the spindle at the same time its not a big concern just something to be aware of.
Its coming along nicely when's the party:beer: ..Clive
When mine started doing this, I found that the cpu heatsink was full of MDF dust...Quote:
Originally Posted by routercnc
I thought I'd finish off this build thread with the final pictures of the control box, machine, plus my long awaited bed upgrade:
Here is the control box with the door finished and 15" monitor mounted:
Attachment 16935
I still haven't wired up the POKEYs (cycle start, hold, stop, feedrate) but the rest works.
And the rest of the machine:
Attachment 16936
The bed was OK but there was often a gap where I wanted to hold something down. It was intended to take a wooden spoil board, and then cutting would happen on top of that. I stripped the old bed out:
Attachment 16937
Then I machined up a drilling jig to drill each end. There were 4 holes. One pair would take an 8mm clearance and the other pair would take M8 threaded holes. On the next cross member the holes were reversed so that a clearance lined up with a tapped hole etc. The idea was to join each cross member into the back of the previous one and build it up:
Attachment 16938
Attachment 16937
Then I added members at the far end. This was to allow cutting pieces on their end and other options. The bed was skimmed to make it level:
Attachment 16939
Checked it against a known straight edge and it looks pretty good:
Attachment 16940
Then drilled a matrix of M6 holes for the clamps:
Attachment 16941
In practice these have not been great and some of the threads have already stripped as the extrusion is only about 4mm thick. I've started upgrading these to M8 which due to the shape of the extrusion will go into a much thicker part.
I've done some machining on the new bed and it is definitely stiffer and gives a better cut than before. Pleased with how it turned out. Will post some pictures of the new bits I've been making in a new thread.
Well you now have a very nice neat machine with a suburb looking control box. Looking at the picture of the spindle do you have a cable restraint to stop the cable breaking at the plug as this could be detrimental to the VFD.
.
Big thumbs up. Happy New Year:encouragement:
Hi Clive
Thanks for the comments !
:welcoming:
Cable is hard wired (no plug) through the cap onto the motor cables. There is a large cable restraint on top of the end cap which allows a gentle radius on the cable.
I did this after the previous one arced at the plug and blew and killed the VFD.:confusion:
See post #27 for another picture. I'm away from PC but I posted on it in another thread when my VFD blew
My next machine will have the cable running in energy chains rather than hanging in midair but I need a new longer cable to make that happen.
Nice work looking very smart!
Hi RouterCNC,
Just spent the day going through your build of the electrical cabinet as you made some good points on my build.
Very interesting build and issues that you worked through along the way, hope mine is half as good as yours ;-)
Are the last posts of the wiring diagrams the most up to date or are there others?
Guess I should move onto your MK4 build guessthere could be some more information in those.
ATB,
Ian
Hi Ian,
MK4 will run off the same control box so there won't be any updates in that log.
In post #95 in this thread showing the wiring diagram there were some changes made after that:
1. 68V linear supply was actually putting out 72V
2. 30V Switched mode power supply was removed (far right)
3. Z axis driver (MD542) bottom right replaced by another DQM860 driver, and powered by the 72V linear supply
4. 5A fuses going to each X driver replaced by a single 10A fuse shared to both (if fuse blows gantry stops)
5. 6A MCB type D uprated to 10A MCB type D to cope with linear power supply inrush current when switched on
6. 5V power supply cable from PC to BOB was replaced with a dedicated 5V DIN rail PSU (mains driven)
7. A green LED was included in the power on circuit when the main switch was switched on
Very happy with it and works well.
Thanks
Many thanks for the reply.
I have been mulling over the design of mine and plan to incorporate many ideas from your build.
Just placed and order with Chalon for a rotary disconnect switch and two type D MCB's 4A & 10A.
On holidays fo rthe next few weeks so taking viso and some cables, plugs and sockets plus soldring iron with me and relax in the sun while building my wiring looms ;-)
Cheers,
Ian
Quote:
Originally Posted by routercnc
Hi RouterCNC
I now have all my bits around me and startng to work through the wiring schematic;
Parts are;
2 off 36V - 400W PSU (for drivers)
1 off 24V 2.5A mini rail mount PSU
1 off 5V - 2A mini rail mount PSU
1 off CP0-10V BOB (cnc4you)
4 off CW5045 (cnc4you)
1 off UC300 (cnc4you)
2 off E-Stops (2 pos NC)
4 off 24V 10A DPDT rail mount relays
1 off 4A type D MCB rail mount
1 off 10A type D MCB rail mount
1 off Rotary panel disconnect
1 off 10A EMI filter (cnc4you)
1 off Green reset (NO) panel push button
2 off 24V fans (blown air into cabinet)
1 off Green panel mount led (5Vdc - live)
1 off Yellow panel mount led (24Vdc - live)
2 off White panel mount leds (36Vdc - live)
DIN rail mounting and red, black, yellow and fused connectors.
Oh and I have been given a PILZ PNOZ 16S safety unit, just not too sure how to incorporate this.
I did notice that you have an Allen Bradley unit, would this be of use to me or do I have enough above?
Hi nairepooc,
It would be best to start a new thread on your build. Also, I wouldn't consider myself an electrical expert, I got through my build after many wrong turns and used the advice of fellow forum members.
I haven't use the Pilz myself, but it is purpose built and used commercially and is well known. Instead I was happy with a standard relay to run all the 24V signal control hooked up to the e-stop circuit and wiring it up manually to create the latch circuit. If I remember your schematic that is what you had done so a Pilz unit is not critical.
This relay in turn drives the 'Allen Bradley' unit. This is a contactor and is a purpose built relay (with lots of features as m_c posted on recently). It uses 24V DC to switch 240V AC. When the control box is turned on you have to press the reset button to latch the 24V circuit. This then sends 24V DC to the contactor signal terminals, which in turn switch the mains (L) and (N) feed to the linear power supply. This in turn powers all the drivers at about 70V DC.
As has been pointed out by others, you could use a normal relay instead to switch the mains so long as it can take the current. I have a linear PSU with high in-rush current so didn't want to go that route. Maybe SMPS is lower in-rush and would be OK - but I'm not an expert.
I had to size my MCBs with some trial and error, and forum advice, to meet my particular needs. You will have to decide if 4A and 10A are what you need in your case, or ask for further advice on those.
Attachment 20209Quote:
Originally Posted by JAZZCNC
I start using spec glasses at 40, try the same Dean:)
Well done Tom digging up the past and upsetting Dean I thought he used a bloody great magnifying glass:glee:Quote:
Originally Posted by Tom J
Only did as I realized that he is on better mood:smiley_simmons:Quote:
Originally Posted by Clive S
Bloody hell You need to get out more if nothing better to do than go back that far to get your Kicks.!! . . . . But I've got pair in every room and vehicle so now I'm sorted.:thumsup:Quote:
Originally Posted by Tom J
..................