[richjones]

The axis limits are fairly easy to work with - each is a normally closed switch which opens when the axis -'ve limit is reached (they don't limit on the +'ve limit).

[I say easy to work with but somehow I thought they were normally open when I got my circuit made up, so I had to use a screw terminal block to get the limits working, rather than just plug them in - bit annoying!).

The easiest way to work with them is to connect them all up in series, connect one side to ground and the other to the 'all limits' line on the linuxCNC computer, along with a resistor to the +5v line (it is just a pull up resistor, so value not crucial. I used about 2Kohm, but it was just the one that came out of the box first. Probably 1Kohm -> 10kohm would be fine (TTL style pull up), and I assume most parallel ports are MOS, so even 200Kohm would presumably work fine as well)

The big problem I had with the limit lines is the impact of noise - I don't think the lines are shielded as they snake around the machine. I had to use a capacitor across the lines and a ferrite ring to remove the impact of the noise.

(I think Emco use 24V on the switch lines, and I only used 5V - this brought the noise problem to the fore - It is completely under control using 5V and the capacitor/ferrite, but I might go to 12V if I was doing it again)

I think that Mach allows software debouncing of the limit switches which would probably solve the problem as well. I don't think LinuxCNC does this, though.

[richjones]

This is what my circuit ends up looking like Attachment 255890

(bit of a mess as I thought I had enough header connectors, but fell short when I looked!)

Two 16 way connectors to connect to the axis (middle) and spindle (left) boards on the Emco. The 26 way connector (right) connects to the computer parallel port. 3x 25ls31s and a 26ls32. There should be decoupling capacitors, but the signals are sufficiently slow that I've just got a largish capacitor on the power input (pins on the far left).

The connector on the top left is for the limit switches connected in series (the other holes are for three NO limit switches - got it the wrong way round!). Under that connector is the pull-up resistor for the limit line.

The empty pin array on the bottom left is for a connector to connect to the Emco power bus - bit of an unknown quantity, so I just connected to the computer 5v line.

Lots of mounting holes with the 1PIN label that I forgot to remove!

I'll pop it back in in a minute to show it all connected.

There are a couple of additional connection points dotted about - most particularly two connections to the parallel port for axis A if I ever wanted one, and a few inputs left spare.

[Fastest1]

The attachment is a dead end on my side.

[richjones]

Couple of pics of it all together...

The board installed in the spare slot (presumably for a tool changer, but not sure):
Attachment 255976
If you look carefully you can see a couple of capacitors across the limit switch input - you can't see the ferrite ring on the wire.

And the whole back:
Attachment 255978
Work in progress and I've not tidied things up at all, but got the computer at the far left, board installed on far right.
I've got the computer hard wired in, so it turns on with the mill.

The computer connects to the outside world by the power connector:
Attachment 255980
I've replaced the RS485 with the computer video-out, and put in a bulkhead usb for keyboard/mouse and usb memory.

As I say, not yet tidied up, but all works fine (I had been worried about noise, but there doesn't seem to be any noise issues on the inputs or outputs.).

[Arjand]

Wow, really impressive Rich. You can make some money with this circuits als many people would like to have them I suppose! Unfortunately the mill 55 is a bit different, but I'll see what needs to be don on that on that one.

[richjones]

Well, if anyone wants to give it a go, feel free to PM me - I've got some boards left over (minimum order quantity!), the components are all standard, and I'd set out the construction steps (all simple). As I said before, I wouldn't mind recouping the board printing costs - but that shouldn't get beyond about £7/$10 or so. Anyway, I'm mainly interested in helping out, not making money on this.

Willywonka - I've only just seen your request - I've responded - PM me... The boards weigh 20g each, so to post them would be about $4 standard post - you'd have to be able to solder, or know someone with the skills (but it is all simple 'big' components, so no hard work). The components are all really easy to get hold of, and it would probably be easier for you to source them locally. The circuit works for me with the mill, but I don't know about the lathe - presumably it is similar but how similar - I'd imagine it has the same spindle controller, but would it have the same stepper driver (or cable pinout). Hmm.

[thunderbt3]

I currently have a fully operational PC Mill 50 setup with PC, controller card and software. It has WinNC but not WinCAM which I believe was only compatible with the 55 series mills. Since I rather make chips than program gcode, I decide to retrofit it with a Gecko G540, new power supply, new steppers, and a VFD to drive the original spindle motor. Would the CNC kit from CNCRouterParts be enough? not enough? over kill? Any suggestions for a VFD?

3-Axis DIY Nema 23 Electronics Kit | CNCRouterParts

The kit seems pretty much bolt on, plug and play. According to the spec sheets for the stepper motors should bolt up to the existing mounting holes without problem. I purchased a defunct control box on ebay from Maxton and gut the electronics out of it for the retrofit. I plan on removing the whole OEM control box and steppers and mothballing them along with the PC the mill came with just in case I would want to sell the setup and keep all the new electronics in the future.

I've been trying to source new stepper motor pullies and belts. The belts I remove have "Optibelt-VR" and "057AG" printed on them. They are 12.7mm wide and I believe 2mm pitch which should make them MXL style. The problem is I haven't been able to find a replacement belt in Optibelt's catalog. I'm guessing they may have switched their product labeling convention. Sourcing pullies has also been difficult and I would prefer not removing and modifying the OEM pullies. Any suggestions?

[cwalker1960]

might give rich's solution a try. other wise just buy some 280 ounce motors , and drivers and a 1 hp vfd ,, the 50 s that i have seen use a 5 phase motor and I couldn't find any reasonably priced drives.. and why wouldn't you use the pulleys that are already there? just drill them out and tap a set screw hole.actually if i had to do it over i would just direct drive the 280 ounce motors as they are plenty strong enough
.. will require making a few brackets , but no more belts or pulleys

I currently have a fully operational PC Mill 50 setup with PC, controller card and software. It has WinNC but not WinCAM which I believe was only compatible with the 55 series mills. Since I rather make chips than program gcode, I decide to retrofit it with a Gecko G540, new power supply, new steppers, and a VFD to drive the original spindle motor. Would the CNC kit from CNCRouterParts be enough? not enough? over kill? Any suggestions for a VFD?

3-Axis DIY Nema 23 Electronics Kit | CNCRouterParts

The kit seems pretty much bolt on, plug and play. According to the spec sheets for the stepper motors should bolt up to the existing mounting holes without problem. I purchased a defunct control box on ebay from Maxton and gut the electronics out of it for the retrofit. I plan on removing the whole OEM control box and steppers and mothballing them along with the PC the mill came with just in case I would want to sell the setup and keep all the new electronics in the future.

I've been trying to source new stepper motor pullies and belts. The belts I remove have "Optibelt-VR" and "057AG" printed on them. They are 12.7mm wide and I believe 2mm pitch which should make them MXL style. The problem is I haven't been able to find a replacement belt in Optibelt's catalog. I'm guessing they may have switched their product labeling convention. Sourcing pullies has also been difficult and I would prefer not removing and modifying the OEM pullies. Any suggestions?

[thunderbt3]

I'd rather not modify the OEM stuff just in case I want to sell it in the future. I would like to create a simple bolt on kit so I can pull all the modern electronics off to save it and just bolt on all the OEM stuff and sell it with the PC it came with.

Direct drive would be good. All that would have to be done is remove the ball screw pulley, install a coupler, and bolt on the bracket and stepper correct?

might give rich's solution a try. other wise just buy some 280 ounce motors , and drivers and a 1 hp vfd ,, the 50 s that i have seen use a 5 phase motor and I couldn't find any reasonably priced drives.. and why wouldn't you use the pulleys that are already there? just drill them out and tap a set screw hole.actually if i had to do it over i would just direct drive the 280 ounce motors as they are plenty strong enough
.. will require making a few brackets , but no more belts or pulleys

[cwalker1960]

[
well that sounds simple enough ,, but it's going to require you making the brackets and probably the couplings ,, and no nema 23 steppers are not a bolt in replacement for the originals . if you want to keep it original . i would suggest talking to rich ,, if you want to get the most out of it ,, convert it



QUOTE=thunderbt3;1606128]I'd rather not modify the OEM stuff just in case I want to sell it in the future. I would like to create a simple bolt on kit so I can pull all the modern electronics off to save it and just bolt on all the OEM stuff and sell it with the PC it came with.

Direct drive would be good. All that would have to be done is remove the ball screw pulley, install a coupler, and bolt on the bracket and stepper correct?[/QUOTE]

[thunderbt3]

My original intent was to convert, but not modify the any of the original parts so I can swap them back in if I sell it. I'm currently pulling all the original stepper and throwing them in the electronics box. I have an entirely separate gutted electronics box from eBay I'll be using for the conversion along with a spare set of x & y stepper mounting plates from eBay so I'll be starting with a clean state. The steppers from cncrouterprats I'm using are 47mm between mounting holes and I thought I measured the same on the original mounting plate. Are originals not 47mm?

[
well that sounds simple enough ,, but it's going to require you making the brackets and probably the couplings ,, and no nema 23 steppers are not a bolt in replacement for the originals . if you want to keep it original . i would suggest talking to rich ,, if you want to get the most out of it ,, convert it



QUOTE=thunderbt3;1606128]I'd rather not modify the OEM stuff just in case I want to sell it in the future. I would like to create a simple bolt on kit so I can pull all the modern electronics off to save it and just bolt on all the OEM stuff and sell it with the PC it came with.

Direct drive would be good. All that would have to be done is remove the ball screw pulley, install a coupler, and bolt on the bracket and stepper correct?

[/QUOTE]

[cwalker1960]

it's been quite some time since i converted one ,, i don't have any original motors to measure but i do remember the bolt pattern was different as was the shaft size,, i turned the motors just slightly and drilled and tapped new holes, but all of that will be different if you go direct drive ,, seems i remember the original motors being around 60 ounce i put 280 ounce back on the one i done .. as well as i can remember i got around 120 IPM after finishing and i believe the belt drive is 2 to 1 so if you direct drive it you should be able to easily get 200 IPM rapids.. i know i could literally ,, and did stand on the z axis and it wouldn't stall after the conversion..
we never had the computer for it so I don't know what the speeds or torque is from the original

[cornmander]

Hi all, I just bought one of these machines and wanted to collect all the documentation on it (besides this extremely helpful thread!) before I started my linux CNC conversion of it. Could someone please pass along the manual to [email protected] ? Thanks in advance.

[1190CNL]

Hey Rich very cool how you got everything to work. I also have a pc50mill. I am interested in trying out your setup if you still have boards for sale.

[gtlegs]

Well, if anyone wants to give it a go, feel free to PM me - I've got some boards left over (minimum order quantity!), the components are all standard, and I'd set out the construction steps (all simple). As I said before, I wouldn't mind recouping the board printing costs - but that shouldn't get beyond about £7/$10 or so. Anyway, I'm mainly interested in helping out, not making money on this.

Willywonka - I've only just seen your request - I've responded - PM me... The boards weigh 20g each, so to post them would be about $4 standard post - you'd have to be able to solder, or know someone with the skills (but it is all simple 'big' components, so no hard work). The components are all really easy to get hold of, and it would probably be easier for you to source them locally. The circuit works for me with the mill, but I don't know about the lathe - presumably it is similar but how similar - I'd imagine it has the same spindle controller, but would it have the same stepper driver (or cable pinout). Hmm.

I am very interested in trying out one of your boards, please PM me your contact information so we can talk through this.

[milkcartonkid]

for richjones

Do you still have any of your boards available? I would like to start learning/using Linuxcnc with my mill and would like to purchase one of your circuits. Great work by the way and thank you for sharing your findings.

[gtlegs]

for richjones

Do you still have any of your boards available? I would like to start learning/using Linuxcnc with my mill and would like to purchase one of your circuits. Great work by the way and thank you for sharing your findings.

Milk, I ordered a few of the 26ls31's, 26ls32's, 16 pin idc sockets, and also got a copy of the electrical schematics from Emco. I am actually working on a PC Turn 50, not a mill, but the spindle and axis drives are very similar. Hopefully will have a breadboard put together this weekend to try it out. Will post my results.

[milkcartonkid]

Awesome gt! Good luck and thank you for all of this

[gtlegs]

So I received the parts and tried them out, but never got the lathe working correctly. Initially I had troubles with getting signals out of the parallel port, finally found an incorrect setting in Mach and got that sorted out. Now, I can get the correct signals from Mach into the machine. I setup one 26ls31 to try and get a stepper moving, but it didnt work. Attached is the wiring pinout I used. after a little research this morning I'm hoping it was just because I didn't have the pins 8 and 16 hooked to anything. Checking with my meter I can't see any voltage coming out of the chip. I was using the x direction output from Mach to test. I am a mechanical engineer, but dealing with electrical engineering stuff is difficult for me. I will try jumpering pins 8 and 16 to the enables to get them +5v and Gnd tonight. Any other advice would be greatly appreciated!

[gtlegs]

Good news and bad news. Good news is it works! I tested both axes and they both moved very smoothly. Bad news is I have to go out of town for the rest of the week. Once I get back I'll get everything buttoned up and try it out!