Digital readout from magnetic or glass scales

The super charged power feed is just about exactly how I would describe how I want my manual converted equipment to be. Having the manual ability but the power assist when wanted. Then I can have the higher consistency, be able to handle the radius and other automated functions better, but not loose the manual abilities. I'll get after the CNC controls one of these days. This is one of the reasons I was looking into what Linux CNC hardware I could use now as a DRO then expand later to full control. I didn't think about using a pi, that may be another route. I do have a extra PC that I could get going with Linux and setup. To many ways to work it out!! I'm teetering on the Shumatech DRO or just getting the Linux parts and getting after it. There was another post with a vendor other than mesa that had some excellent solutions also. Four port serial board that plugged into a mother board with a serial output. It appears that I may have enough room with that solution that I could setup both the lathe and the mill and toggle between machines. (As they share a vfd anyways)


Thanks again!

andypugh wrote:

An Arduino and LCD shield ought to work, or you could look at using a Raspberry Pi or BeagleBone running LinuxCNC .
In those cases you would be using general purpose IO, and there is a chance that you might run out of count-rate at high axis speeds. But then how fast can you move an axis on a manual lathe?

FWIW I think having a lathe converted to CNC is massively useful. I rarely use actual G-code, I use pre-written routines like a sort of super-charged power feed.
(Face off to this length at this surface speed, feed and cut, turn to this diameter stopping at that point).

There is a (boring) video here of me making a part that way. I can't imagine going back to manual handle-twiddling.
It is especially useful for threads, you can cut any thread at any pitch at all. My macros are even set up so that I can type "19 tpi" and the box changes to "1.3368" as the lathe is set up in metric.

Well I am still leaning to the linux cnc as I may be planning some CNC integration in the future. The beaglebone looks like a good solution. Now to figure out how to connect the serial RS422 to the BB and start getting setup.

I may order one today just to give it a shot.

Any places to go for BB support or people that have had experience with it?

Thanks!

Jake

Get a couple of board like this one: www.ebay.com/itm/RS485-Board-3-3V-SP3485...&hash=item3cd2da4ccc
Or solder a couple of RS422/485 transceivers on a piece of breadboard. Make sure you use 3.3V types or use a regular 5V part like the humble 75176 and a resistive divider to scale the output voltage of the transceiver to 3.3V

Well I have finally come around to getting closer to this.

For now I bought a TI launchpad, and will use the TouchPad android app for my DRO

I still want to try to connect the scales to the PC to try out that route, but I have searched to the end of the internet and still have not gotten a firm grasp on how to connect the TTL glass scales to my PC.

Thanks again for all the help!

So having 4 scales, I need to get either a 4 port serial to pci card or a parallel port card then build a box with the serial ports in it. How do I need to connect the serials to parallel? They are TTL scales.

I have a CNC mill in sights I just need to get them knocked down to what I am willing to pay.

Thanks for the links Andy, I think viewing at work has blocked some of the pages as I had never run across those pages before. I have some reading and hopefully comprehending to do!

ok I think I have made some headway on wrapping my head around the parallel port.

So the data pins 0-7 I would need to configure 4 of them as outputs with the clock signal, and four of them as inputs. The first 4 with the A scale connected and the four inputs with the B connected. The zero to the grounds, and the grounds to the chassis ground. The only thing left is the 5volt source which seems like there is a big variety of options there.

Is this closer to correct now?

Thanks guys!