[Krenovian]

I'm in the process of converting my NM-145 from the factory VFD and spindle motor to a three phase AC induction motor and appropriate VFD using the Shadowspawn LLC retrofit kit. My NM-145 came with a proprietary BOB which doesn't have 0-10vdc analogue output to connect to the new VFD so I'm replacing it with a C11G BOB from CNC4PC. I have a couple of questions which I've emailed Novakon but haven't heard back from them so I'm asking here to see if anyone can help.

The first question involves the proximity sensors on the NM-145. I have determined that they are NPN, normally, open and that they require 6-36 vdc to operate. I need to know if they have an internal pull up resistor and if so what the value of that resistor is so I can make the appropriate connection to the C11G BOB with the appropriate external resistor. The sensors I have are manufactured by Chuanyue Automation System Co. LTD and are the model LJ12-Z4NKG45. I've looked at an English translation of their website and can't find the info. there.

My second question is about the factory BOB. It is labeled "Novakon.net Rev 1". Does anyone have any documentation or a manual for this BOB? Here is a picture of the BOB. Thanks for any information you can provide.

Attachment 207346


Curtis

[SCzEngrgGroup]

Seems a little nutty to replace the entire BOB, and do so much re-wiring, when you could simply add a spindle control board alongside the Novakon BOB for about $30 and an hours work. The Novakon BOB has optos on all the inputs, which gives you the pull-ups needed for the prox sensors for free. And, it's nicely "connectorized", making it easy to remove/replace should it ever fail.

Regards,
Ray L.

[Krenovian]

Thanks for the input Ray. That hadn't occurred to me.

Curtis

[SCzEngrgGroup]

Take a look at the spindle control boards offered by HomannDesigns.com. They are excellent, easy to setup. You can get the PWM signal from the 6-pin connector on the Novakon BOB to drive it (the mating connector is a Molex "MiniFit" plug, which is available from Digikey and Mouser). +5V and Ground to power a spindle control board should be available on the screw terminals on the Novakon BOB. You won't need to touch any of the existing wiring.

Regards,
Ray L.

[Krenovian]

Looks like the Homann DC-05 DigiSpeed MC board would do the trick. Thanks for pointing me in that direction Ray.

I'm still interested in obtaining the information indicated in my original post. I'm one of those people who wants to know as much as possible about their equipment. I was one of those kids who took his toys apart to see how they worked then couldn't put them back together or broke them in the process.

[SCzEngrgGroup]

The prox sensors do require pullup resistors - they are open collector outputs. AFAIK, there is no publicly available data on the Novakon BOB, but for the most part, it is pretty straight-forward - buffered I/Os to/from the parallel port, and opto-isolators on all other inputs. There is a PIC processor that control the main power relay, and monitors the Mach3 charge pump input.

Actually, I'd be willing to bet populating the missing components on the top-right corner of your photo would give you an isolated analog PWM output on Pin 2 of the 6-pin connector.

Regards,
Ray L.

[t300]

Just curious, is this an early or a late nm145? I believe in the last few months of its production novakon switched to some "updated" components.

[Krenovian]

T300,
It is a late model NM-145. One of the closeout machines purchased in the late winter of 2012.

Ray,
Thanks for your input. That's an interesting possibility, adding the missing pieces to the board. Any thoughts labeled PCI, PCO, and GND are for? They are located just to the right and below the 6 pin connector for the spindle. I'm assuming a jumper would be placed on these? Seeing as my machine didn't come with a user's manual I really didn't expect there would be any documentation for the board, but it never hurts to ask.

Curtis

[Krenovian]

Ray,
Thanks for your input. Interesting idea adding in the missing components on the board. Any idea what the three pins labeled PCI, PCO, GND are for? They are located just to the right and below the 6 pin connector for the spindle in the photo. I'm assuming a jumper would be placed across them in some manner. Seeing as how the mill didn't come with a user manual, I didn't really expect there would be any documentation on the BOB, but it never hurts to ask and you've provided some good info. Thanks.

Curtis