Technical Tinkering

Technical Tinkering

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In this blog I'll try to keep you posted on the progress of my current projects. They are mainly of a technical nature like Electronics, CNC machining, Amateur Radio etc. Come in and look around!
I welcome your comment, which you can insert by clicking on 'Comments(.)' at the bottom of the page.

Aciera F450 Conversion

CNC stuffPosted by michael Jul 13, 2014 01:08:25
Back after a long period of silence. I started rebuilding the control system of an Aciera F450 milling machine. Originally the machine was fitted out with a Fanuc CNC controller. After someone pulled some boards for cleaning, the controller went dead. Why would anyone store the firmware in battery backed-up memory and put the battery on the backplane?
Anyway, the decision was made to rebuild the machine with Linuxcnc and Mesa boards.
For the motor drives, Granite Argon drives were obtained. Really great drives, with the ability to find the commutation points by wiggling the motors at startup. That feature comes in very handy as the Aciera has Fanuc motors which do have rather odd commutation signals. On the Web you can find boards that use these signals for initial commutation and switch over to encoder position after one revolution. Quite nice, but that solution would have added another $500 to the project cost. So we decided to let the Argon drives sort it out themselves.
The actual rebuild started with taking out the original Fanuc controller parts. Patiently we traced all the external wiring, plugs and terminals and drew up diagrams of that part in order to facilitate the wiring of the MESA cards later. Then we wired up one of the motor drives and started testing the lot. Disappointment was our reward. The first axis moved rather strange. It turned out that the signals from the encoder were erratic. Closer examination learned that the line driver had gone bad (accidental supply line reversal?). Replacing the line driver chip in the encoder (Fanuc Pulsecoder) cured the problem. The next test with the Argon Granity tool went successfully. We succeeded in tuning the x-axis so there was virtually no overshoot or following error. So far I am very happy with the Argon drives. Configuration of the drives could be documented a bit better though. However, in practice, it turns out to be easy: check the right boxes and the drive 'knows' how to behave. (the z-axis will present a challenge since the motor also has to support the weight of the table and I haven't found a torque offset parameter yet)
Next came tsetting up of the computer and MESA cards and doing some preliminary testing. We will discuss this in the next posting. I'll also will make put in some pictures.

  • Comments(2)

Posted by Stepan Apr 01, 2015 16:45:04

Ups, I forgot my email adress =).. zaruba@banksys.cz

Posted by Stepan Apr 01, 2015 16:31:58

hello Dear PE1ROK.

Really sorry for my bad English but I really need your help with your older NAVTEX receiver, that I want to build. But I have some problems with:

1) how you did oscilator part for 516,5 kHz? I saw that you used 9,814 MHz
oscilator and two 74HC161 dividers, but how? =).
I am not able to calculate dividers ratio / procedure you used for the 516.5 KHz.

2) I don`t know why, but band-pass filter (first part) still oscilating at cca 1.4kHz without signal on input

3) Please, I need to know how you modified PIC software for 1.5 kHz.

Would It be possible to send some schematics of other parts ?
(I try to "merge" your schematic with instructions and schematic from Mikael Nordman`s NAVTEX, because he used very simple input section and 6/18 kHz IF)

Really thank you for you time and have a nice day
Stepan Zaruba
Czech Republic
(26 feet long sail boat sometimes sail on Baltic sea=)