Wednesday, November 18, 2009

The Atom Mobo is Alive!

The motion constrol system requires a PC to work.... obvious isn't it...

For EMC2, we can use Pentium 4 with 512Mb or more. I had a free P3 donated. but it Ubuntu didn't like it... An used P4 of the correct spec will set me back ~RM400, It is the most economical choice but I have a soft spot for the Intel Atom chip...

Purchased a D945GLF box. Its contained  mobo + the N240 processor at RM215. I need to have a ATX PSU, a 2Mb DDRII RAM, and use salvaged LCD monitor, keyboard mouse,  HDD, CD drive.

Plug in all the necessary connectors, slot in the RAM, power up... then all hell broke loose for the next 3 day trying to figure out what went wrong.... after swapping a new DDRII RAM, IDE cable, BIOS battery, keyboard, mouse, CD drive and even another HDD. Eventually, it was concluded that the mobo is faulty and while waiting for replacement, (warranty claim), I got hold of the Dual core Atom board D945GLF2 as they only have this in stock...

Back to me workbench, slot in the RAM, plug in all neccessary connector, set the bios, insert the EMC live-CD & we have this

Ran the latency Test, 15,801ns max jitter is  just what I hope for.

Here is the screenshot (literally) of EMC2

Lessons learnt? Yes, Murphy Law never fails!!! ....

Apart from that, check your PSU pinout!!!

The D945GLF requires  2x10 +2x2 power connectors.

The D945GLF2 requires  2x12 + 2x2 power connectors

Getting the right PSU at the right price burnt up 2~3weeks of my time....

So you are warned.

Thursday, November 12, 2009

Featuring EMC2

While settling back in my home town, I found time to evaluate the CNC Controller bits.

After pain staking search and review; I end up PC based CNC software controller
1) Mach3 which runs on Window
2) EMC2 on Linux OS

As I wish to have the flexibility to have the last say on the hardware specifications

I eventually ended with EMC2 which is free open source program. Not that I'm cheap, Mach3 is affordable ~USD100, & you can have a trial version for unlimited period for free, it has all the bell and whistles that any top rank controller programs would have. Moreover, help forums and supporting community are strong too.

It is the believed that Open source Linux OS is practically immune to hackers & deathly viruses which I fear most.

About the software

  • EMC (the Enhanced Machine Control) is a software system for computer control of machine tools such as milling machines and lathes.
  • EMC is free software with open source code. Current versions of EMC are entirely licensed under the GNU General Public License and Lesser GNU General Public License (GPL and LGPL)
  • EMC provides:
    • a graphical user interface (actually several interfaces to chose from)
    • an interpreter for "G-code" (the RS-274 machine tool programming language)
    • a realtime motion planning system with look-ahead
    • operation of low-level machine electronics such as sensors and motor drives
    • an easy to use "breadboard" layer for quickly creating a unique configuration for your machine
    • a software PLC programmable with ladder diagrams
    • easy installation with .deb packages or a Live-CD
It does not provide drawing (CAD - Computer Aided Design) or G-code generation from the drawing (CAM - Computer Automated Manufacturing) functions.
  • It can simultaneously move up to 9 axes and supports a variety of interfaces.
  • The control can operate true servos (analog or PWM) with the feedback loop closed by the EMC software at the computer, or open loop with "step-servos" or stepper motors.
  • Motion control features include: cutter radius and length compensation, path deviation limited to a specified tolerance, lathe threading, synchronized axis motion, adaptive feedrate, operator feed override, and constant velocity control.
  • Support for non-Cartesian motion systems is provided via custom kinematics modules. Available architectures include hexapods (Stewart platforms and similar concepts) and systems with rotary joints to provide motion such as PUMA or SCARA robots.
  • EMC runs on Linux using real time extensions. Support currently exists for version 2.4 and 2.6 Linux kernels with real time extensions applied by RT-Linux or RTAI patches.

EMC2 is precompiled with Ubuntu 8.04 LTS (long term support) versions for ease of installation and longevity.

EMC2 has a few GUIS, Namely, AXIS, TkEmc, HALUI. They even has a Ladder Logic program call CLASSICLADDER. For now, I'll concentrate mainly on AXIS which is an ongoing development.

Screen shoots