Denford novamill electronics build log

Hello welcome to my build log!

I bought a denford novamill, it didn’t come with the control box so I decided to build my own control box and operator interface. This is my diary!
Attachment 24237

I bought 2 sheet metal enclosures, one is 600x400x300 this will house all of the power and drive components. The other is 600x400x120 and this will be for the operator interface.
I managed to source the correct connector for the machine made by harting and some industrial multi core cable and some screened cable witch I had left over from another project. http://www.mycncuk.com/threads/11102...=Emco+retrofit
Using some aviation type connectors I made up a cable to provide power to the machine and receive limit switch signals from it.

Attachment 24243

I then went eBay shopping for the rest of the components.
Attachment 24240
For the spindle drive I got a Parker 508 dc drive, it will power the dc motor with the 180v dc 8A it requires.
X y and z axis stepper motors will be powered by dm542 digital stepper drives.
I designed my own safety circuit with fuses, contactor, and mcb’s.
I made it all look tidy with some slotted trunking. I did by best to separate the control signal wires from the ac and dc power by routing them around the outside whilst routing the power trough the centre. Any crossovers are at 90 degrees and I utilised shielded cable where applicable.

Attachment 24246

For this build I will be using linuxcnc specifically the 5i25 fpga card and the 7i76 breakout board from Mesa electronics in California.

https://youtu.be/-fzOLPta0xA

The power supply for the stepper drives will be 40 volts or thereabouts, I got a toroidal transformer and a rectifier circuit and made my own power supply.
Attachment 24241
The power supply for switching etc is a 24v 3a switching power supply.
Here’s the control box almost complete:Attachment 24242
I’ve left a space so I can add another drive for a 4th axis later.

That’s it for the control box for now as I have some decisions to make before I finalise the design, I’m not sure if I need a spindle reverse circuit and a spindle encoder I will decide that another day.

I’ve made a start on the operator interface. For this I’ll be using a 17” touch screen monitor and a waterproof keyboard. The aperture at the bottom will house the start/feed hold buttons, a feed override pot, and a spindle load meter.

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Is that a 7i76 Mesa I spot in there?

Quote:

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Originally Posted by Clive S

Is that a 7i76 Mesa I spot in there?

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Yeah:wink::wink::wink:

Today I temporarily plugged in the machine and configured linuxcnc. I needed to cut an i/o plate for the cabinet. Specifically the holes for ac input, cooling fan and plugs for the machine. I had previously machined the outside profile on a machining centre as it was too big to machine on my denford mill.

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I’ve left a couple of locations empty, one will be for the mpg and the other for a 4th axis.

Nice work, keep the pics comming.

Enjoy the Novamill. I got one also without electronics and followed a similar route with DM542 drives etc, but using Mach 3. Have been using it now for 6 years, very pleased with it, a nice machine.

I received my motherboard
Attachment 24340
It’s an Asrock mini ITX with Intel Atom D425 and 4gb ram. Linuxcnc has a program included in the package that lets you test the mb to see if it’s suitable for use with linuxcnc. Although it’s not that important as I will be using the fpga card to generate the stepper steps. This motherboard appears to be more than fit for its intended purpose, it’s tiny size will help with the install I’m sure.
I’ve also salvaged a 250w itx power supply and 120gb SATA hd from an old pc. It took me about an hour to plug it in on the bench, install linuxcnc from a usb and copy the files from the old pc to the new one. So it’s now ready to be installed in the cabinet...somewhere...
Attachment 24341

Anyone considering building an electronics project like this please take my advice, when you see a cabinet you like for your project, buy one that’s 30% bigger��

Here are the pc components ready to be fitted into the enclosure which also houses the operator interface. I made the decision to put them here instead of the other enclosure which houses the electrical components which drive the machine. I hope this will allow me to interface the operator interface directly to the computer hardware, avoiding any unwanted electromagnetic interference.
Attachment 24388
I have a piece of abs to mount the components but I may change this to aluminium plate at some point as this plate will also be a rear mounting plate for the keyboard. Next I need to find a suitable flexible conduit or something simalar to connect the operator interface to the drive control enclosure. I will need it to run a 12v power supply to the screen and computer hardware. It will also be used for the parallel cable which connects the Mesa 7i76 breakout board to the 5i25 fpga card. I still need to decide wether to use a separate breakout board for the control interface or wether to run all of the buttons mpg and feed/spindle override knobs back to the 7i76 in the other enclosure.
I’d be grateful for advice on this.

Awaiting bits and pieces being delivered to complete the computer hardware install and I was bored so I added the speed and feed override encoders. Also labelled all of the connectors and buttons with my labelling machine. I will possibly engrave them later as I believe they will peel off by tomorrow.
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It’s been a while since I made any reportable progress but last week I finally had a chance to make a start on finishing off the build of my denford.
Here’s some pics:


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I’ve now changed the keyboard for a storm interface stainless steel one, and wired in my buttons for the start, pause, feed override and spindle override.
I raised the mounting of the operator interface for better comfort when using the touch scree controls and also to make it better for keyboard input. Not that I’ve used the keyboard for input though, I’ve been using fusion for all my work.

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Hi, Just on the off chance, do you have any details on the transformer you used for the steeper motors, the TXR-0736P05A toroidal power transformer 300VA.

I have the spec, just not a wiring diagram.230V 50Hz input, 27.5v at 10Amps output

It was a long time ago, but I had this saved in my YouTube history, maybe you will find it useful
https://youtu.be/4OoQQg76ar4

Best of luck!

Thank you, very interesting, but different transformer competely :-)

video one is 625VA, made may 2017, one in this thread is 300VA and dated May 2018?

I have looked at your other videos.
230V 50Hz input, 27.5v at 10Amps output.

Designed and manufactured to BS EN60950 and BS EN61558.
Complete with integral 85ᵒC Thermal cutout NC, and thermistor 10kΩ for Temperature Measurement and protection.

Dimensions 115mm OD x 60mm height. Weight 2.55kg

Includes mounting hardware.

Input Connections PVC flexible leads to 7 way JST in line connector

Output Connections PVC flexible leads to 6-32UNC ring crimp

Full specification and drawing available.

http://www.toroid-tech.com/clearance...nsformer-300va
Attachment 29457