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Message |
    
Gerald_D
Registered
Username: Gerald_d
Post Number: 202
Registered: 11-2005
| | Posted on Wednesday, August 23, 2006 - 07:03 am: | 
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Open source http://www.linuxcnc.org/ runs under Linux. Works via the parallel port and is apparently a viable option for the MechMate (alternative to Mach series) - no hardware changes needed. |
Mike Richards
Registered
Username: Richards
Post Number: 25
Registered: 05-2006
| | Posted on Wednesday, August 23, 2006 - 04:15 pm: |
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Switching to EMC might require some heavy lifting (software wise). It requires a real-time operating system - not just the plain vanilla Fedora or SUSE Linux that most of us geeks use.
When I downloaded the source onto my Fedora Core 4 system, I moved it to the customary /usr/local directory and then gave the standard tar -zxvf command to unzip everything. It created the proper directories. However, when I ran the .configure --enable-run-in-place command it carashed when it couldn't find the rt directory. After a little sniffing around, I realized that rt = real-time. Since EMC runs through the parallel port, it has to have extremely tight control over the interrupts to generate step pulses at the correct interval. Normally Linux runs a lot of tasks concurrently, giving each a slice of time depending on their priority. That works very well for most things, since waiting a few milliseconds for the computer to get back to the spreadsheet or word processing document would be transparent to the computer operator, but that same delay would not work when you're controlling stepper motors.
Perhaps the easiest way to get started is to follow the basic installation directions:
Basic Installation
The best way to get started is to install Ubuntu (5.10 Breezy Badger or the newer 6.06 Dapper Drake LTS), and then follow these instructions to install EMC2 on it. This procedure will automatically install a realtime kernel, and will allow you to easily and automatically keep up with future EMC2 releases using the Ubuntu update manager.
I haven't done that because I have issues with Ubuntu - but that's a personal vendetta which has nothing to do with EMC. |
Mike John
Registered
Username: Mikejohn
Post Number: 52
Registered: 12-2005
| | Posted on Wednesday, August 23, 2006 - 04:24 pm: |
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I once heard a conversation where somebody asked "Is there any difference between the CPL and ATPL with ILS VOR for the IR?"
Everyone in the room, except one, understood perfectly.
The one who didn't understand was not a pilot.
The above makes just the same sense to me as that sentence made to the non-pilot.
In fact, I'm not certain your not taking the micky.
It's not April 1st, is it?
...............Mike |
Mike Richards
Registered
Username: Richards
Post Number: 26
Registered: 05-2006
| | Posted on Wednesday, August 23, 2006 - 06:11 pm: |
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Mike J.
Linux is Linux - meaning that, although it's the world's greatest operating system, it is NOT friendly if you're a new Linux user. It requires significant knowledge on your part before it will do its magic. Ubuntu was written for those who just want to pop in a CD and go, which is the main reason that I don't use Ubuntu. (To me a Linux system requires tuning - lots of tuning - before it plays sweet melodies.)
Linux is also a multi-tasking, multi-user operating system. That means that more than one task (program) can be run at one time. It also means that more than one person can be logged onto the computer at one time - which is how I control other Linux computers, anywhere around the world, from my home office. Because Linux is a multi-tasking, multi-user operating system, it can't be relied on to do anything at exactly the precise millisecond. The way around that problem is to use a Real-Time operating system. Basically Real-Time means that if something is supposed to happen every 0.5 milliseconds, it will.
For us non-pilots, I Googled the following:
CPL:
Commercial Pilot License
ATPL:
The Airline Transport Pilot License (ATPL or ATP) is the highest level of aircraft pilot certification. Those certified as Airline Transport Pilots are authorized to act as pilot-in-command of an aircraft in air carrier service.
ILS:
The Instrument Landing System adds glide-slope, or elevation information. Commonly called the ILS, it is the granddaddy of them all when it comes to getting down close to the ground. In every sense it is a precision approach system and with the most sophisticated equipment it can guide you right down to the runway—zero Decision-Height and zero visibility.
VOR:
VOR, short for VHF Omni-directional Range, is a type of radio navigation system for aircraft. VORs broadcast a VHF radio signal encoding both the identity of the station and the angle to it, telling the pilot in what direction he lies from the VOR station, referred to as the radial. Comparing two such measures on a chart allows for a fix. In many cases the VOR stations have a colocated DME to provide distance measurement allowing for a one-station fix.
IR:
Instrument Rating refers to the qualifications that a pilot must have in order to fly under Instrument Flight Rules (IFR). It requires additional training and instruction beyond what is required for a Private Pilot certificate or Commercial Pilot certificate, including rules and procedures specific to instrument flying, additional instruction in meteorology and more intensive training in flight solely by reference to instruments. Testing consists of a written exam and a practical test (known more commonly as the check ride). The check ride is divided into an oral part and a flight part.
For most private pilots, the most significant value of flying under IFR is the ability to fly in instrument meteorological conditions (such as inside clouds). Additionally, all flights operating in Class A airspace must be conducted under IFR. In the United States, an instrument rating is required when operating under Special visual flight rules (SVFR) at night.
The VHF Omnidirectional Range navigation system, VOR, was probably the most significant aviation invention other than the jet engine. With it, a pilot can simply, accurately, and without ambiguity navigate from Point A to Point B.
The widespread introduction of VORs began in the early 1950s and 50 years later it remains the primary navigation system in the overwhelming majority of aircraft. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 203
Registered: 11-2005
| | Posted on Wednesday, August 23, 2006 - 07:38 pm: |
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The only word I understand is ubuntu |
Evan Curtis
Registered
Username: Evan
Post Number: 8
Registered: 12-2005
| | Posted on Wednesday, August 23, 2006 - 10:44 pm: |
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I like that word. This forum (and those participating) reflects that ideology to a great degree.
Thank you one and all. |
Dick van Randen
Registered
Username: Dvanr
Post Number: 7
Registered: 03-2006
| | Posted on Thursday, August 24, 2006 - 01:09 am: |
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ubotu:
A botter is a botter because of other botters
 |
Gerald_D
Registered
Username: Gerald_d
Post Number: 204
Registered: 11-2005
| | Posted on Thursday, August 24, 2006 - 08:10 am: |
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You_got_a_bot_too?
(The u's in ubuntu are pronounced the same as you and too) |
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CNC - motion control software