Now that my control panel actually look like one :) I need to figure out the BOB.
I am using the PMDX-122 BOB & Leadshine M860 Microstepping driver. This is what I came out with...
Attachment 7304
Please comment freely & correction is mandatory as I know I still hasn't got it right yet...

I am trying to achieve the followings
1) charge-pump feature,
2) fault feature,
3) BOB respond to the E-stop circuit,
4) Bob to turn on/off turning on the spindle c/w manual override
5) bob to turn on/off the steper motor power c/w manual override
6) Future PWM spindle speed controller

Ken,

since you have J4 free, it might be a good idea to use that to drive the stepper?

Did you check if the BOB can drive two stepper at the same time?

PS: Glad to see you have EMC running, I tried yesterday the whole evening on my laptop but the latency-test doesn't give me good results. EMC people say it's a hardware issue, but I am seriously wondering if MACH3 will also not work then.

Ries

Ries,
2 reasons to leave J4 free,
1) EMC2 doesn't have master/slave drive option as in Mech3. I learn from here that PMDX-122 can source ~35ma and my driver only sink 15ma nominal as stated in the manual, so I guess they one pot for 2 drivers should work.
2) future A-axis? maybe.... :D

I have problem with Live-CD with my notebook as well, but once I disable the power management, the WIFI, the LAN, the sound card, connect an external LCD monitor then it works just fine. Didn't give time to find which works as I'm more interested in dedicated mobo for EMC2. Have a go, should be fun.;)

Guys,
I did more manual digging and found out I made a complete mess out of the earlier layout, I came up with a hopefully "less wrong" schematic for the BOB & drivers

Attachment 7307

I really need help with this one, electronics & computers are really not my forte... so are a lot other stuff :o

Please comment freely and laugh at my mistake, I know I still has a lot to learn.

Thanks in advance.

Cheers

Ken

Ken, I haven't bothered to strip my EMC systems down, because they're fast enough to support the 500 IPM or so rapids on my MM. So I still have the network running, etc.

I could probably reduce the jitter, but it doesn't seem worth it to me. If I were going to do it, I'd remove or disable the network and sound cards, run the display with a 2D, BIOS based driver (a VGA, or frame-buffer mode that doesn't use any of the acceleration features of the GPU), and then shut down any extra background processes (daemons / services) in the system.

My MM is out in a garage shop about 30 feet behind my house. I generally develop my cut files on a computer in the house, and then squirt it down the (wired) network to the MM computer. I then walk out, set up, and cut.

Hey Ken,

could you please post a picture in a higher res. Some parts of it are not readable.
Thanks a lot
Claus

Here is the higher res.
Attachment 7322

Normally the power gets connected to the top 2 points on J8. That bottom point is marked as an output.

Do you seriously want nine limit/home switches?

Sounds like I'm over doing?? I blame it on overly safety conscious as I read of 500ipm travel...
The limit switches are USD0.90 a piece, good Japanese made Omron. When compare to proximity switch (US$15++), they are less accurate but I question the need for extreme accuracy. IMHO, for MM's application, the machine (0,0,0) position is set using zeroing technique for every single job, the sensor zero position is for parking purpose hence even a few mm off the mark won't hurt anything. BUT I can be wrong about this & I'm all ears.
Attachment 7325
I have yet to buy all but 6 mechanical micro switch for now... 9 is for minimum academic consideration, each axis have an end limit at each end of the travel & a zero(parking) position. BUT if its not necessary, the surplus can go elsewhere such as door alarm, mouse traps... etc :D

Thanks for the heads up, I'd edited the power input. Will post a fresh revision once the following are cleared.

1) will the E-Stop & limit switches scheme (J5 & J6) work correct?
2) I am not sure of JP1, JP2, JP3, JP5 & JP6.
3) Is it safer to let the PC to switch on the stepper motor power supply rather then having them power up all the time?
4) Is there anything else I missed out?

Thanks in advance.

You are overdoing the limit switches. For example, how do you detect when a cutter has gone too far in the z-direction? Suggest that you get a better understanding of Limit Switches - optical / mechanical / proximity and see that all switches easily go on one series circuit (similar to e-stop).

Thanks for the lead, I did spend a considerable effort trying to understand that thread but still cloudy. Have to consider 5V (4.2V after the PMDX), debouncing. Therre are schemes to use relays, logics or even micro processor...

This limit switch thingy is holding up progress of my build, since the MM can operate without them, I would have to leave it out until I know what to do.

Now I need to find out more about Zero-plate, apparently this is essential.

The PMDX discussion has been copied into one thread here

I have finally done it! I fried my PMDX-122 & the Mobo!!!

I tried to finish off the control panel this year if I want to get a number below #100.

I wired up the relay & E-stop circuituit + the E-stop, everthing went nicely.
Tested the Stepper motor PSU & got No load ~54Vac on the secondary & ~75Vdc at the capacitor. Loaded with a light bulb & I got ~48Vac and ~65VDC loaded.
then I wired up the tranny to the Power relay circuit & when I pressed the push buttons & the contactor made that familiar "thub!" sound when press the ON button &" tuck!" sound when pressing "OFF" & the E-Stop switch.

So far so good.

Wire up the Mobo to the BOB & BOB to the stepper driver.
It boot up nicely upon power up & suddenly the monitor went blank. I get thermal overload massage upon reboot... & I lost the keyboard & the mouse.... I check the BOB & it was fried even depriving me of a good smoke show or a tiny "bang!"...

Its almost midnight, I just pack the whole box up & stow it away in the store room until I get another BOB.

I'm jinx when it comes to electronics..... :mad:

I will order my steel tomorrow.

Ken,

this is odd...

Why do you think the BoB is fried?

THis could only happen if:
1) the input voltage on the BoB (7VAC or 12VDC) was way to high.
2) The came some voltage from the driver back into the bob

I don't have your drivers specs at hand, but assuming they are opt isolated, it mist be a power supply that was wrong.

Did you measure the voltage on the BoB's power supply?

Ries

Hi Ries,
I replaced the D945GCLF & confirmed that the mobo is partially fried.
Bob did not power up when I supply power to it.
I'm very sure I supplied 12Vdc from the harddisk power connector to the Bob and a DMM measurement confirms it.
I re-powered the Bob & I don't have any LED lit up.
The driver is opto-isolated & it even wasn't powered at the time of test...
Another abnormal is the parallel cable turn very warm.

Anyway, I ordered the steel & just received them.

The main 178x76 C channel are very straight. They have to! as I paid premium (double) for these imported Japanese channels. Judging from what I read from other build, twisted channel can be huge PITA.

I'll set up the angle grinding rig before I could start making some grind sparks soon.

Ken,

This sounds like if some ground current is running somewhere.

how did you ground the BoB and PC combination? Is the BoB and/or PC in any way connected to the metal of the control box? This is currently the only path I can imagine that could be problematic.

Did you try to connect the BoB on 12VDC without the printer cable?

Sorry to here that components are fried...

Ries

Steel Fabrication
 

Hi guys
Just an update on my progress.
I shelved the control box & ordered a chinese BOB rather then sending the PDMX122 for repair, it will be more costly in shipping in my part of the world.

Had been cutting, drilling and tapping all this while,

Here are the steel stock scattered all over the floor,
Attachment 8086

Steel stock cut to size so far,
Attachment 8085

Drilling with the guide bar,
Attachment 8088

Tapped completed
Attachment 8090

Dry fit the table for motivation.
Attachment 8087

Dry fit the Gantry
Attachment 8089

I can find straight flanged angle iron here so I will use T-bar instead. Will cut one of the short flanges with the grinder skid & work from there.
These are the 60x60x7thk T-bar. Looks like I have quite a bit of sanding to do...
Attachment 8091

Progress is slow, but its moving...

yes, it`s takung shape...:D

I'm in the process of cutting the rails.

The design say its 1.1" ~28mm, I end up with 33~34mm on the shorter flange, after I cut one of the short flange on a 60mm x 60mm x 7mm T-bar flange. Can I stick to 31mm?

I am prepared to use 30mm board rather the 25mm MDF to bridge the difference.

You can stick with 31mm. There is no issue with the MDF. The issue is whether your motor plate will swing down low enough so that the pinion gear goes under the rack. For the Americans with 1/2" square rack it is easier, but the rest of us use 16mm square rack. If you have decided that you are using big pinion diameters, you could modify the motor swing plates a bit.

Garald,
Thanks for the prompt reply. Just to clarify if you meant 33mm rather then 31mm.

If I can omit the chore to reduce the flange height further, I'm happy, will put a note on the motor swing plates, will get there somehow... Its 9pm, I'd been grinding the whole day... need to "play" with the video editing dor a while before I call it a day.

Your question was: "Can I stick to 31mm"

But, the same reply fits 33mm. :)

Thanks, that will save me at least a day of grinding.

I started grinding the rail today, after 5 hours of grinding, I'm only half done on the first rail.... Does it really take that long? or I did something wrong?

The grind is very slow, I set the leading edge of the grinding wheel lower the then the traling edge by a quater of a screw turn.

The contact on the grinding disc is right at the center.
Attachment 8150
It is very to get the rail ground evenly throughout the length, but I'm very please with what I saw till now.
Attachment 8148
Attachment 8149

nice and shiny..:)

A whole day of grinding continues today...

I can't seem to grind any further the 2mm deep, the ground surface is 3mm wide....

I see everyone able to grind a pointed knife edge...

Will mine be enough for the V wheel?

Thanks in advance.

Ken,

The goal is to grind until you have a 1 mm top edge width...not a knife edge.
It can be slightly wider. Just check that the V-wheels are riding on the 45 degree sides, not on the top edge.

Ken: The trick in grinding the angles is to get the leading edge of the wheel to contact the steel first so it will cut with a downward angle. I found this made to job a LOT easier and faster. I just used two fewer washers on the bolt in the front than on the one in the back that rides along the rail. As the cut progresses, I just removed washers to lower the cutter but always with two less in front than behind. Worked like a charm.:) Don't get discouraged, we all go through this phase - It's a rite of passage!

Couldn't had describe it better!

Thanks Joe & John.

I played with the down cutting angle this morning & apparently it works like a charm once it is correctly set.

Will proceed to the last length, hope to have the rail complete by end of the day.

Finally reached the 1st milestone of my MM build...
Finished all the grinding & cutting work on the rails, after... I lost count of the time...

Heres the whole lot
Attachment 8195

& a close up shot.
Attachment 8196
A video will come shortly...