CNClinux+motion controler+Servo-Any advice Please?

Hi
My name is Vagelis and i am from Greece.
These days I am going to make some decisions about my cnc router electronic part

The machine that I am building will have
2.2 KW Water cooled spindle
1500mmX800mm working area
4 yaskawa servo motors (step-direction mode)
2 X SGMPH 400 Watt for x (the long) axis. That means Slaved axis, as two motors will move the gantry.
1X SMAH-400 Watt for y ( that moves z axis)
1XSGMAH-200 Watt for z

All these motors with yaskawa servo drivers
All motors have 2048 cpr with quadrature encoders and are rated at 3000 rpm. That means I will need 4*2048*3000/60=409600 pulses in order to keep using the accuracy that the motors offer. In other words I will need a motion controller that can produce at least 410mhz pulses. I have been told that the parallel port of a pc (even under linux or windows) can’t produce such high rate pulses in a reliable way. I have read that linux ( as a real time operating system) is far more better against windows but not as good to use parallel port in such high pulse rates( 400mhz+). Also I don’t want to use electronic gearing. The decision that I have to make is even go with

Solution A
Windows+ Mach3( or Mach 4) with motion controllers like
IP-CSmio-p
Ethenrnet smooth stepper ESS

OR

Solution B
CNClinux
With mesa motion controllers.

I have already made an internet search about solution A as the helpful people of www.mycncuk.com forum help me. The truth is that so far I didn’t find too much information about the linuxcnc solution for my machine. While looking the MESA electronics site I couldn’t understand what kind of controllers I will need.

Before I write down any question, I think that you must have in mind
1. I can install any version of linux in a pc but I am not an experienced user. That means I I am not familiar with console command line but if it will be necessary I will try and do the best I can
2. Last years I am a windows based system user
3. When I come against the electronics connection I will need support

Question 1
Is there any one who can tell me what mesa motion controller I will need for my machine?

Question 2
Is it easy with linux cnc and mesa motion controllers to have slaved motors ( for my x axis)?

Question 3
What will be the cost for the above solution


Question 4
Except the mesa motion controllers will I need some other equipments (BOB, Spindle speed controllers etc)

Question 5
Is there any other solution with linuxcnc, other than Mesa motion controllers

Thanks for your time

Hello. I sell Mesa in Europe so my advice can be suspicious.

I would recommend that you use a 7i76 + 5i25 or 6i25.
With this set up you will be able to step dir the drives (that you have) + output a analog signal to the spindle.

I think that there is a "gantry" configuration that deals exactly with the problem of controlling both X motors (I am not sure!).
If there is no "pre made" solution then the simplest way is to send the same step/direction to both X drives and in case that one enters in error (or with a very low following error) the system should completely stop.

There are other solutions, like Pico boards or the plain parallel port.

I forgot to mention that 409600 is "just" 0.4096 MHz
The 7i76 is able to reach about 8 MHZ = 8 000 000 Hz

the biggest problem with linuxcnc and 'slaved' axis motors is the homing/unracking problem.
If you need the homing process to 'unrack' the axis ( home each side ) there is no easy, direct way.
There are workarounds. or maybe this is not a problem with your machine.

Chris M

I have made several machines "gantry style" but I always try to place the motor on the middle of the gantry. I normally use a larger motor mechanical attached to the gantry ends with a stiff shaft. This removes all the problems related with controlling two motors.
In your case the machine only have 800mm, so it should be very easy.