KBCC-125R DC tach question (new CNC mill build).

[krakenatwork]

Hello everyone.

    I'm planning a new build.  I'll purchase a BF-20L clone (Grizzly G0704) and build a CNC mill out of it.  I already selected most components:

Mill: Grizzly G0704 (BF-20L clone)
ballscrews/mounts/other mechanical stuff: CncFusion premium kit
Electronics: CNC4PC C11G breakout board, CNC4PC C16 limit switch board, CNC4PC C3 pulse generator (tach/spindle angular position)
Drives: Gecko G203V
Steppers: Keling KL23H2100-50-4B (50V/5A/570 oz-in torque)
Spindle drive: KBCC-125R from fleebay.
DC tach (connected to the KBCC to close the  feedback loop)
A 48V/12.5A DC PSU for the steppers, 2 smaller ones (5V/3A and 12V/1.2A) to power the electronics.

   You can view my diagram below:


   
  My main question regards the KBCC (I have read on the forums that some people have used them):

   It's written in the manual http://www.kbelectronics.com/manuals/kbcc_manual.pdf:

        "If control is used on a reversing application, the tach wires must also be reversed so that positive (+) is always connected to B or T."

   As far as I understand, it means that the T pin (I have a 7V/1000RPM tach) is connected to the + wire when driving the spindle clockwise, and I must use something (I used a mechanical DPDT relay in my diagram) to reverse the wires so the DC tach is still providing positive voltage to the T pin.  Am I interpreting the manual correctly?

   Also, I'm worried about transients; even though the KBCC is built (and connected) to handle forward-brake-reverse operation, what happens when the relay reverses polarity while braking (negative voltage will be applied momentarily to the T pin).  Should I add a diode in-line with the tach?  will it screw up the RPM by 10% (a diode usually has a 0.7V forward bias voltage, and the tach outputs 7V/1000RPM)?

   If anybody has experience with these DC motor drivers (or other similar drivers), I'll be more than happy to read your comments.

Thanks.

   

[DICKEYBIRD]

I cannot tell you how spooky this is.  I literally just this minute walked into the house from testing the exact same setup!  Exact same KB controller, exact same Servo-Tek tach and I've had the same worries about polarity reversal during spin down.  Even more so in my case since I'm working with a lathe and it could have a heavy 4 jaw chuck on it for some jobs.

As to your question; I really don't know.  I can tell by your posted diagram, you're way further up the food chain electro-magically speaking than I am.

I hooked mine up & tested it in the forward direction only 1st and can happily report that it works great as far as speed regulation goes.  I hooked it up per the manual; (+) to T, (-) to I2 and moved the J2 jumper up 1 position.

One of my experienced mentors on the HSM forum said the polarity reversal shouldn't be a problem on the later versions like mine but unfortunately it is.  When I reversed motor direction without reversing the tach input, the motor went WFO with no speed control.  Fortunately I was prepared and shut it down instantly with no damage done.  I then reversed the tach connections, started the motor in reverse, all was normal with good speed control.

So that means that yes, we must do the DPDT relay thing, dangit.  As far as your diode question, I don't know but I'll ask around and post back if I find out anything helpful.

 

ps: Tell me more about this "CNC4PC C3 pulse generator (tach/spindle angular position)"  That sounds very interesting.

[krakenatwork]

Thanks Dickeybird!

    What happened to you is exactly what I expected; when the voltage goes on reverse on the tach, the system adds a negative error to the output in the closed loop, making the motor go in the opposite speed delta (faster rather than slower), which increases the negative error, this goes again recusively and the system simply locks at flank speed.  Luckily no harm done on your side.  BTW this is what happened on a rocket, simply because a detector of sorts was connected in reverse (from memory it was either the first Ariane-5 launch or a Delta rocket launch).

    I've written to KB electronics to get some technical info about the KBCC's reverse operation with a DC tach. (to complement the lacking info in the manual).  No news yet.  I'll send you any info I get (IF I get any...)  Let's hope :-)

    Now, regarding the C3 pulse gen; I can tell you one thing: you'll need one for your lathe! :-)  These are used to connect to Mach3/EMC2 and give either a speed indication, closing the feedback loop between the asked speed and the actual speed, and they can also be used while threading/tapping by generating an index mark.

   Look here http://www.cnc4pc.com/Store/osc/product_info.php?products_id=129 for more info, there are manuals to help you plug it into to your break-out board.

   I'll also be using their c16 optical limit switches instead of mechanical switches.  I think it'll outlast standard mechanical limit switches, and will cost a fraction of the cost of industrial ones (like Honeywell).  The remainder is pretty classic; Gecko drives, standard steppers.  Maybe in the future I'll add digital encoders and/or digital drives, that'll depend on how well the machine will work.

   For rigid tapping, I'll search fleebay from time to time and if I can grab a procunier tapping head for cheap, I'll jump on it.

   For now, I've bought part of the stuff and I'm piling up cash to buy the remainder. 

[DICKEYBIRD]

Now, regarding the C3 pulse gen; I can tell you one thing: you'll need one for your lathe! :-)  These are used to connect to Mach3/EMC2

Silly me!:doh:  I totally missed the "C3" in your post and saw only "pulse generator" instead of the "index pulse card" description I'm more familiar with.  I already have C3's on my lathe and my little Denford MicroMill.  They're great!

I did a some further manual perusal re: tach signal reversal and in the supplement they show the tach (-) signal connected to the "F-" terminal on the "TB2" terminal block on the KBCC instead of the "I2" terminal on the speed control.  Dunno if that will make a difference but I'll try it and see.

I have a wire connected to the "F-" terminal at the moment so I couldn't just slap the tach wire on without making sure what that wire is hooked up to.  I THINK it's the inhibit circuit but I'm not sure...which brings up another sore subject.  I had a miserable time getting my spindle under Mach control with the C11 due to my inexperience and total lack of isolation knowledge.  I finally got it working after a LOT of fiddling (and a KBSI-240D Signal Isolator) but didn't take any notes or draw a diagram of what goes where & why.

I'm trying to do that now but I've got SO many wires crammed into my one wire channel with only a few colors it's gonna be a nightmare.

[krakenatwork]

I did a some further manual perusal re: tach signal reversal and in the supplement they show the tach (-) signal connected to the "F-" terminal on the "TB2" terminal block on the KBCC instead of the "I2" terminal on the speed control.  Dunno if that will make a difference but I'll try it and see.

I don't think it'll make a big difference, I just took my multimeter in "continuity test" mode and both pins seems to be directly connected. 

I have a wire connected to the "F-" terminal at the moment so I couldn't just slap the tach wire on without making sure what that wire is hooked up to.  I THINK it's the inhibit circuit but I'm not sure...which brings up another sore subject.  I had a miserable time getting my spindle under Mach control with the C11 due to my inexperience and total lack of isolation knowledge.  I finally got it working after a LOT of fiddling (and a KBSI-240D Signal Isolator) but didn't take any notes or draw a diagram of what goes where & why.

You could probably just splice the tach's "-" side to the "F-" signal, along with the other wire.  Since the I1 and the F- pin are directly connected, it could be your inhibit signal, or it could be the ground-side of your 0-9VDC variable signal that controls the spindle speed.  What I find strange in the manual is that "voltage following" mode uses P2 and F-, and what I read over on cnczone was that you can connect a KBIC (smaller brother to the KBCC, no reverse, in an import small lathe or mill it's most probably a Chinese knock-off) using 0-7VDC between P1 and P2.  I prefer to follow the manufacturer's advice, though.

I'm trying to do that now but I've got SO many wires crammed into my one wire channel with only a few colors it's gonna be a nightmare.

Yep, this can look like a meatball spaghetti in no time.  I've bought a lot of spool ends (75-100ft), that's what remains when the shop buys large spools and splits them in 100-ft rolls they usually sells, and the remaining incomplete rolls go for sale at 1/2 the price.So far I've got 4 colors of 20AWG (orange, gray, blue and green, I'll try to grab some white, black yellow and red, specially after reading how much a headache it can become), I also bought a roll of shielded 4/18 wires for the steppers, and 2 large 2.5" emergency stop switches, along with some safety switch covers for toggle-switches (http://www.acceselectronique.ca/lesite/product.php?id_product=5272).  I'll use one of these on the "limit switch override" switch, to make certain I don't switch it to "ignore limits" by accident.

The mess this can become makes me remember one of my first jobs, where I had to find my way through a patch panel used by the network, phones and the PBX (phone system).  It looked like a complete mess (and it was) before I unplugged the wires one at a time, straightening them, tying them, labeling them, and plugging them back.

Back on topic: As I understand, by using the mechanical relays the way I do, and since the C11G's variable-voltage output is opto-isolated, I don't think I'll have to use a KBSI.  Time will tell, though, I'll let you know when I get there.

Have a nice day!

[DICKEYBIRD]

Thanks for the input.  Yeah I figured out later that the F- connection won't make a difference.  I'll have to wire in a polarity reversing relay at some point but I think I'll leave it alone for now as I don't really need threading at the moment.

I hope you hear something back from KB that will help us.

As Elmer Fudd said: "Be vewy, vewy careful with CNC4PC boards and that cwazy isolation stuff."

[DICKEYBIRD]

I had a closer look at your schematic and wanted to complement you on it.   Your method of controlling the KBCC is much better than mine and I think will help me solve an issue or 2.

If you don't mind, what program did you create that with?  If I do another retrofit, I'll definitely do as you have and map out the components before I get started.  This lathe has changed numerous times with wiring & component changes over & over.  Quite a learning process for this old man!

[krakenatwork]

Hi Dickeybird!

    Thanks for the comments, I did the schematic simply using google (to find images) and... mspaint.  I wanted to use something like Visio, but I don't have it at home.  I have been searching for an open-source software to do the same, but at the time "DIA" was pretty basic.  I might jump to LibreOffice Draw (I have LibreOffice installed on my PC already), that would make the sketches much easier to edit.

  I found a few that might be worth a try: http://www.maketecheasier.com/5-best-free-alternatives-to-microsoft-visio/2012/01/20

    Regarding the way I control the KBCC, I figured out the KBCC is not 0-5V compliant on it's inputs, but the fwd/brake/rev ones simply have to be connected to each other to select which way to go.  I simply used 2 relays in series: the "onboard" mechanical relay on the C11G and an external one.  One is used as an "on/off" switch, the second one in series simply switches fwd/rev.  The "truth table" goes like this:

A    B   |   OUTPUT
-------------------------
0    0   |    Off/brake
0    1   |    Off/brake
1    0   |    FWD
1    1   |    REV

"A" being the signal sent to the on-board relay, and "B" being the signal sent to the external one.

I planned this setup so the "on/off" relay is normally open (you have to power the coil to make the spindle to turn), and the "FWD" position is normally closed (you have to power the second relay to go in reverse).  I figured that one more often makes the machine run on forward than on reverse, so there's less chance of having the spindle to stop in case a brownout occurs, because the relay momentarily switched polarity (summers getting quite windier over time around here).  At least with a KBCC it won't break anything if this happens.  An added bonus is the relay will be activated less often and it should live longer :-)

   Out of curiosity; are you using EMC2 (on Linux) or Mach3 (on windows)?

[DICKEYBIRD]

Mach3 is what I use.  I looked at LinuxCNC since it supports a "real" spindle encoder instead of Mach's single pulse/rev with the parallel port.  Unfortunately, Linux is waytoo far up the computing food chain for my meager skills.

My C11 has 2 on-board mechanical relays.  I wired the pin 1 operated relay NO contacts to close on M3 command for forward, pin 16 relay NO contacts to close on M4 for reverse.  Both relays open gives braking/off.  The braking works awesome by the way.  My setup works OK for now but I may change it up later.  I'm having trouble "figgerin' out" (I'm from Tennessee) how to actuate the DPDT  tach signal reverse relay without adding yet another relay.  Not smart enough to figger how to do it with the remaining C11 relay NC contacts without leaving a coil powered up all the time while in forward.

I'd like to trigger the tach reverse relay off of the KBCC somehow without hacking into it.  It will effortlessly switch from forward to reverse even if you send an M3, wait for full speed, skip the M5 and hit it with an M4.  It brakes the spindle down to a dead stop RIGHT NOW, clacks and spins up backward without a whimper.  Gotta love KB.

[krakenatwork]

Did you order the C11G specifically with 2 mechanical relays?  I'm finding the CNC4PC website a tad confusing, since there are 2 revisions of the manual, one sports 2 mechanical relays, the other one mechanical and one solid-state, but nowhere I've been able to find if it's available as an option or if it's an "evolutionary" thing (Darwin's into electronics nowadays?  ).

I think I'll place an order in the next weeks/month, so I wonder.  Next will be the PSUs and steppers, then the mill and the retrofit kit (CNCFusion's)

Regarding Linux, it's not what's bothering me much.  I'm a computer systems analyst, and I've worked on many UNIX/Linux platforms.  They're not as tough to install/manage as they were in the past (I had to install my first "slackware" distro on a '486 PC - circa 1995 - , over a SCSI cd-rom through a SoundBlaster-16 sound/SCSI hybrid card; it was a bios-less card, so I had to pass a truckload of parameters at the boot prompt simply to boot from the CD, not to mention disk paritioning nightmares which were quite "hands-on")  It's the EMC2-related part that intimidates me; as I understand, it's more versatile than Mach (can control multi-axis robots and unconventional machines as well as mills and lathes), but as always it comes with the other side of the medal; complexity. 

OTOH: LinuxCNC is available as a boot-from-CD distro too, might be an easy way to try it.  It uses Ubuntu, which is AFAIK one of the friendlier (maybe not friendliest) distros around.  Since it's built over the LTS (long-term support) version of the distro, this means security patches should be available for a long time.  Using a prebuilt distro is far easier than having to build emc2 from source (belive me, building from source can be a very nasty thing when you hit package dependency and versioning issues)

I guess I'll have next winter to thinker with EMC2, perhaps as a dual-boot to Windows/Mach3 on the machine I plan to use.

What do you mean by

I'd like to trigger the tach reverse relay off of the KBCC somehow without hacking into it.

?

The way I used to control the relay looks like - to my own surprise - the "Run-Brake and Forward-Reverse Switches" in KB's "KBPB & KBCC-R SUPPLEMENTAL INFORMATION" doc, if that's what you mean (page 1, 1st column, 2nd row).  I don't know how well it could integrate to Mach3/EMC2 though; needs an "on/off" and a "direction" signal.  I used 5V relays (they switch on with a 5V "TTL" signal that the C11 will output, but they can handle up to 250VAC/220VDC@3Amps on the other side; since the KBCC should put out 28VDC@ a few milliamps, the relays should be more than tough enough, I guess).  Bought them at Digikey, along with DIP sockets (16 pin) and block terminals, so I solder the sockets to the proto-board and plug-in the relays, if I blow a relay the repairs will be easier.  All components are 0,1" pin spacing so they're standard and pre-drilled proto-boards are easy to find.

Thanks again for your comments!

[DICKEYBIRD]

I bought the generic C11 board (no G or T suffix)  It comes equipped with 2 mech. relays.

I have the LinuxCNC auto-boot CD and played with it for quite a while.  Didn't have much trouble with running it but when I got down to the point of setting up a dedicated PC and actually making it run the lathe my head exploded.  After spending a lot of time on the support site & realizing the high level of computer smarts that are needed, I tossed it and went back to Mach for good.  It's plenty hard enough for my skill level but the support site guys are fabulous as long as you're using the demo version or have purchased a proper license.

I control the KBCC using both C11 relays' NO contacts using the "Foward-Brake-Reverse Switch" hookup (3rd column, 1st row)  That made sense to me and works great with the C11 & Mach.

The problem came when I tried to figure out how to hook up the tach polarity relay.  I have it wired up & working with a manual feed to the DPDT relay coil for testing but where/how to source & switch the coil control signal has eluded me so far.  It'll come eventually though if I leave it alone for a while.

[krakenatwork]

The problem came when I tried to figure out how to hook up the tach polarity relay.  I have it wired up & working with a manual feed to the DPDT relay coil for testing but where/how to source & switch the coil control signal has eluded me so far.  It'll come eventually though if I leave it alone for a while.

I've done a small sub-diagram showing what I understand from your setup:



I think you can simply take pin17 output (set up your C11 to enable the relay signal to be fed through the outputs as I read somewhere the C11 can be configured to duplex the parallel port's pins 1 and 17 so you get 2 different outputs on 1 pin; one for the relay, one for the output pin of the C11 board).  I guess it's pin 17, but I'm going from memory for the C11G board, on the C11 it might be a different pin.

If you're set-up this way, the pin 17 is the "reverse" signal you need to feed to the DC tach's DPDT relay.  Connect the pins as per my complete diagram, so when the mill is ran in the forward direction, the NC contacts are used (eg: the relay defaults to forward), and the polarity is reversed when the C11 activates the "reverse" relay.  Quick and easy fix.

If I didn't understand your setup, please feel free to correct me, I'll be more than happy to help.

Good luck!

[krakenatwork]

Read on the C11's description page:

All pins can be used in a concurrent manner. You can use all the input or output pins in a concurrent manner. For example, if you are using output pin #1 to control the Built-in Solid State Relay Board, you can also access that signal from the output pin on the board or from the DB25 connector for output. Each connection will not affect the other current from the other connection.

I read (diagonally) the C11's manual and couldn't find any info about duplexing pins 1/16... I might have dreamt it...    Anyway it's one less thing to worry about; simply use pin1 or pin16's output to control your relay and you should be good to go.

[DICKEYBIRD]

See, I knew the solution would come to me eventually. Thanks a lot!:beer:

How much power do you think the pin output can handle?  The relay I'm using (had it on hand) has a coil that needs 75mA @12V.  I probably need to get a much smaller one like you have.

[krakenatwork]

Hi!

  I prefer port wine over beer, but thanks (I know a good LBV - a Colheita - ~12 years old that's from out of this world!)

  From the manual, it says: max output voltage = 0,55V (the 5V psu's voltage + 0.5V), typical output 44mA.  Tou'll definitely need something like the ones I bought (URLs are from digikey.ca, but you can buy them from their US counterpart or somewhere else, you'll have the part numbers):

    http://www.digikey.ca/product-search/en?x=0&y=0&lang=en&site=ca&KeyWords=v23105a5001a201

    5V/30mA on the coil, 220VDC/3A on the load side

    something like that to hold the relay:

    http://www.digikey.ca/product-detail/en/1-390261-4/A100206-ND/1125624

    and something like that to wire them on the proto-board (16-30AWG so 20AWG will be just fine):

    http://www.digikey.ca/product-detail/en/282834-4/A98335-ND/1153265
   
    I bought my proto-board locally:

    http://www.circuittest.com/pc-171-1215-pads-215x39mm.html

   I took some pictures of it besides the KBCC to give you a sense of scale (I installed one extra socket; I'll buy one extra relay sometime, along with a pair of terminal blocks):

Top-side:


Bottom-side:


Bye!

[DICKEYBIRD]

Awesome, thanks for the schooling!    These are areas I've never worked with before.  I'll do some ebaying this week and get some stuff on the way.

[krakenatwork]

Hi!

BTW here's a small schematic of my relay board, out of laziness I made it so there was not much to solder (only where there are big colored dots, 24 dots per relay.  Afterwards I also soldered the remaining DIP socket's other pins to the board, for strength):



Fun thing, using the "Circuittest PC-171" "split-in-the-middle" pc-board, I had no copper trace cutting to do.  Total lazy job 

Keep me in tune when you'll have more experience with your DC tach, a video on Youtube might be fun, to see a dead-stop and a fwd-stop-rev in action 

[DICKEYBIRD]

Keep me in tune when you'll have more experience with your DC tach, a video on Youtube might be fun, to see a dead-stop and a fwd-stop-rev in action 

Good idea and I'll do m'best to do that.  There's at least you, me & 1 other guy that'll get excited watching a KB do it's magic.

Prolly be a little while as work & home life ratcheted up a couple notches in the past few days.

[DICKEYBIRD]

I ran into this http://www.ebay.com/itm/5V-4-Channel-Relay-Module-Switch-Board-For-Arduino-PIC-ARM-AVR-DSP-PLC-/290896116684?pt=LH_DefaultDomain_0&hash=item43bac27bcc

Will this work from the C11 outputs?  Heck I can't buy the relays for that money!

[krakenatwork]

Hi!

   I thing it should work just fine:

This is a 5V 4-Channel Relay interface board, Be able to control  various appliances, and other equipments with large current.

  The board seems controlled by the 6 pins on the board connector.  The presence of transistors and resistors seems to indicate there must be 2 pins used for power (+5V and GND), and 4 for the signals.

  The relays are SPDT though; you can put 2 in parallel to emulate a DPDT relay (useful for the tach reversal).  An SPDT (single pole, dual throw) can switch one signal between 2 output pins, like an on-off-on switch, simply without the middle "off".  A DPDT can switch 2 independent signals between 2 sets of output pins.  It's like 2 parallel "on-off-on" switches taped together.  (or 2 three-way light switches).

   So by feeding 2 relays with the same input signal, you're building a DPDT out of 2 SPDT.

   It would definitely be interesting to find the pinout of the board before placing an order.  (did you also see the 8-relay board that sells for 12$? I'm jealous!  )

   All in all it should draw very low amps from the C11, and it will probably need to be powered from the same 5V power-supply (easy wiring job).  It handles 10 amps, so it should be good to handle the KBCC's few milliamps@28VDC

  Last-minute add: I saw this: http://www.amazon.com/SainSmart-4-Channel-Relay-Module-Arduino/dp/B0057OC5O8, it has the same 6-pin connector, on the board it's written "GND IN1 IN2 IN3 IN4 VDC", so I think we have our answer.

   I was having a serious project-rash, so I downloaded LinuxCNC's last CD and installed it on my old 'puter (that I kept precisely for this purpose), and I also bought a B4CPM-077T treadmill motor I intend to use on the mill someday (direct-drive spindle mod + high-speed bearings to bring the 2500RPM max spindle to something like 5000RPM).  It's specs are: 6600RPM@130VDC, 2HP, 15A max

   I figured out some interesting figures; it should still pull-out 1 3/4HP at least at 90VDC, and it should spin at a little above 4500RPM.  I used specs from another motor and did some interpolation/extrapolation math to figure out the HP, and since the motors are linear, the RPM computation was a single rule-of-three.  I'll fetch the C11G in the next weeks, and I'll be able to start experimenting too. 

[DICKEYBIRD]

Hey "Krak", (I feel like I know ya but don't know yer name)

A fellow on another forum where we were discussing the generator polarity issue suggested tapping into the RY1 coil connections on the A.P.R.M.'s main relay and use that to switch the tach reversing relay.  That would certainly prevent any temporary wrong polarity issues.  He said it's a 110vdc coil so I guess a dropping resistor to match the voltage to the relay coil would work?

I say this because yours is still "on the bench" and the module could be easily removed to access the back side to see if there's an easy way to tap in.  Mine is stuffed into an enclosure with all the wiring tied down and I don't want to rip everything back out.

Also, I guess you never heard anything from KB?

Happy Memorial Day!

[krakenatwork]

Hi!

    It might be an interesting idea; do you mean tapping into the on-board relay's coil contacts?  I searched for RY1 on my APRM (APRM-3 A57099 rev-A02), there's a transformer coil on the other board.

    I'll try snapping a pair of alligator leads to the relay and i'll buy a 90-120V relay to try this.

    The treadmill motor is on it's way

Bye!

[DICKEYBIRD]

...do you mean tapping into the on-board relay's coil contacts?  I searched for RY1 on my APRM (APRM-3 A57099 rev-A02), there's a transformer coil on the other board.

Yes, RY1 on the diagram in the manual is the coil that pulls in the relay contacts for motor reversal.  Should be a perfect source of power for the generator polarity reversing relay coil.

Someone else recommended adding a bridge rectifier to the generator output to eliminate polarity issues.  Sounds good other than the voltage drop across the bridge.  That'd prolly screw up the low end of the speed range.

[krakenatwork]

Someone else recommended adding a bridge rectifier to the generator output to eliminate polarity issues.  Sounds good other than the voltage drop across the bridge.  That'd prolly screw up the low end of the speed range.

Yea, I thought about something like that, and I dumped the idea exactly for the reason you mention.

I think the relay idea is probably the best one.  The motor I bought has been shipped, hopefully I'll get it somewhere next week.  I'll start experimenting ASAP, probably after a quick trip to one of the local electronics shop (120VAC relay).  I'll try to locate the pin under the relay (mine's tis one http://www.newark.com/te-connectivity-potter-brumfield/t92s11d12-110/power-relay-dpdt-110vdc-30a-pc/dp/04F1206).

According to the PDF, it's the 2 ones that are at 90degres from the 6 others.  It should be easy to solder a wire under here from one side, the other side though is another story...

[DICKEYBIRD]

Hi, me again with an elec. question.

I put together a little board with 2 reed relays (5v 20 mA coil) to trigger the generator reverse relay and a cutting oil pump relay switched on & off by the C-11's pin 16 & pin 9 terminals.  You think I should add a suppressor diode across the relay coil or does the C-11 already have enough protection?

[krakenatwork]

Hi!

IMHO I don't think a diode is required for this use, the only current flowing through the coil will be provided by the C11 (@5VDC), and this should be minimal.  The current going through the reed switch won't interfere with the coil's voltage (relays and reed-switches are an isolation method based on magnetism, another isolation method being opto-isolation).

Just make certain your coil doesn't pull more amps than the C11 can output, and my guess is you're good to go.

Bye!

[krakenatwork]

Good news: I got my DC motor!

I did connect the minimum stuff and it ran great; I was able to make fwd/brk and fwd/rev moves with the small relays connected into a 5VDC power source (they switch the signal for fwd/rev/brk on pins S1, S2 and S3)

I had to take care; the pulley is screwed to the shaft using a left-thread, so when I put the motor in reverse the (cast-iron) pulley unscrews itself out; nothing a little bit of thread-lock couldn't take care of (for tests) or a keyway (in the future).  The motor has a small shaft that protrudes in the reat (1/4"), tht'll come handy to connect the tach to it.

The bad news: I blew up the KBCC...

Since it ran great in open-loop (but it was making the motor overspin then freewheel for some time), I wanted to go the next step; connecting the blue wires I thought were the field coil out of the motor.  Big error; the mains fuse blew up.  (read afterwards the wires are for a thermal switch to protect the motor)

I then removed the "field wires" from the KBCC, but a blown mains fuse happened again.  I saw/smelled nothing burning, but since the motor still seems OK (it still has a bit of "notchiness" in it when spun by hand, and it produces voltage when I spin it).

The KBCC was "off" (pins S1-S3 opened; brake mode) when I connected it the second time, so I guess something grounded itself.  There's no troubleshooting manual for these drives, so I guess I'm stuck and I have to buy another one. 

Morale of the story; never short out pins F+/F- on a KBCC...

[DICKEYBIRD]

Ouch!  Man, I'm sorry to hear that.  Sounds like some of my exploits with electrical stuff.  You should be able to fix it though or get just the KBMM-125 speed control by itself without the A.P.R.M.

I have a treadmill motor on my little lathe and almost made the same mistake.  Fortunately someone educated me about the extra 2 wires & thermal switch. AFAIK all the inexpensive treadmill motors are permanent magnet types without wound fields.

I discarded the flywheel/fan, cut off the threaded section, turned a small pulley to fit and milled a flat on the shaft for setscrews.  I also made a plastic duct and mounted an 80mm server fan for cooling.

[krakenatwork]

Well, I just purchased another one on ebay.  My wallet hurts.

I'll try to debug the old one, or sell it for parts, but I am thinking about keeping the beefy heat sink for the stepper drivers...  They'll remain cool 

Since both boards are mostly made of simple components (discrete transistors, a few op-amps), it might be not-too-tough to locate the blown parts; the manual lists the replacement parts required; I even have an old toaster-oven I could hack as a SMT soldering oven... (google "homemade reflow soldering oven toaster arduino" just for the heck of it  ) It would be a project in itself.

Looks like more delays 'till the working CNC mill...

[krakenatwork]

Okay, new KBCC came home this week, plugged-it in, worked better than the previous one, even though the KBMM is of the earlier model (with through-board ICs rather than SMT ones (smt = surface mount).

I tested it on the same motor; motor's really fine and runs very smooth.

Next step: do not blow it... 

I machined a coupler to join the servo-tek DC tach to the motor; mounted the tach and gave it a spin (without connecting it to the KBCC).  Not only does the motor runs smooth, with the KBCC's help it runs steady (without load).

I hooked the tach's wires to my multimeter, and gave the motor a go; at full speed I get 35.6V from the DC tach; this in turn leads to a nice 5085RPMs 

Following the math on the KBCC manual, I get a value of 28906 ohms for the tach resistor; in the 5% resistors world, this leads to a 30000 ohms.

My former KBMM board didn't have a J1 jumper wire (there was a set of holes where standard jumper pins could be installed on the board, but nothing connected to them).  My new one does have a 20-ga (or so) wire.  Did you have to cut a wire on your board to enable the DC tach?

On the other hand, I used alligator clips to connect to the APRM relay's coil pins.  The relay has around 110VDC between coil pins and activates my 2 SPDT relays (couldn't find DPDT 110VDC relays locally so I "created" a DPDT from 2 parallel SPDT relays...)  I'll use these to reverse the relay's polarity.

I'll try to locate some terminals that could be used instead of alligator clips, else I'll build terminals myself out of thin brass sheet.  There are 2 designs I'm thinking about; either "j" shaped terminals that'll slip over the flat pins on the relay (and hopefully lock in place) , or spring-clamp style.  I'll let you know about these when I'll get there.

[krakenatwork]

woopsie!  double-post...

[DICKEYBIRD]

Mine has a simple jumper you move to set it up for tach use...nothing to cut.  Not sure if yours has the jumper??

Here's the manual http://www.kbelectronics.com/manuals/kbmm_smt_manual.pdf

[krakenatwork]

My new KBMM is this model: kbelectronics.com/manuals/kbmm_manual.pdf

My former one didn't have a jumper, it was an SMT like yours, with a twist; it had the place to solder a jumper base but nothing soldered there.  My new one (older model) has a jumper wire ("J1" being a loop of ~20ga wire to and from the board.)  It's old technology for jumpers, first Commodore 64's "1541" floppy drives had these to set the device number, you had to cut a wire to change it, or get your soldering iron to set it back.  Many people soldered a block of 2 dip switches instead of the jumper wires.

I'll probably solder a small switch to the loop; old ideas have a long life

[DICKEYBIRD]

Finally pieced together enough shop time to get the tach-generator & relays setup working.  I really gotta thank Kraken for educating me on the proto board & DIP sockets stuff.  I had never really done that sort of thing before and it made wiring up this project a breeze.  I got a few boards, a bag of DIP sockets, terminals and some relays from Electronic Goldmine very reasonable.  http://www.goldmine-elec-products.com/  The relays came with built in suppression diodes.

Here’s a few pics of what I cobbled up.  The larger board mounts inside my lathe’s base unit.  The 2 small 5V relays are switched by Mach via pins 9 and 16 on my C11 B.O.B.  Pin 16 pulls in one of the relays & switches on the 12V DPDT relay in the tach output when M4 spindle reverse command is called.

The other (pin 9) relay pulls in the big onboard relay when M8 is called and sends 12V to the cutting oil pump on the back side of the enclosure.



The back of the boards ain’t real pretty but hey, they work great!





Here’s a pic of the tach polarity reversing board mounted in an auxiliary box on the back which houses the KBCC-125R speed control.  Initial tests showed that the reverse polarity spike that occurs during spindle deceleration after powering down from a reverse spindle run did give the control a big jolt.  Never did pinpoint what happens exactly but it sure didn’t like it based on the short ”ka-whiz” noise it made every time.  Fortunately no smoke was lost.  I added a couple diodes in the wires between the relay & the KB terminals T & I2 and the problem was solved completely.  There was a .6V drop across the diodes but a simple adjustment of the min/max speed pots had it working perfectly.



Here’s the tach-gen mounted on the back of the Baldor ¾ hp motor.  Crude but effective mount system.  I used a short bit of rubber tubing as a coupler.



 

Here’s the acetal plastic motor shaft adapter I made using a Mach3 wizard…one of the first items I made on the CNC lathe.



Here’s the cutting oil pump.  It’s an old Suzuki 250 dirt bike oil injection pump mounted on a homemade housing & coupler driven by a 12V auto sunroof motor I had lying around.  It pumps just enough cutting oil to keep the work shiny with oil but not so much that it makes a huge mess.  The output is easily adjustable via the bellcrank that used to be hooked up to the throttle cable.  The Denford ORAC lathe sits on top of it’s controls cabinet and wouldn’t do well with flood cooling.