I need your experience for my new setup. Mesa, Beckhoff or Raspberry pi?

Hello to all.

I'm using LinuxCNC about 10 years with parallel port PC on several machine. They were succesfull setups.

But now I have a new project and I think that something needs to be change...

Let me explain my new project;

• 5 axis, step/dir driven motor drivers
• 1 home switch for each axes, totaly 5
• 1 end switch for all axes, totaly 1
• 1 e-stop
• 4 extra digital outputs
• 2 extra digital inputs
• Sum up;
  • OUTPUTS: 5 step, 5 dir, 4 digital output
  • INPUTS: 9 digital inputs

 

• The LinuxCNC is going to run on Raspberry pi ( not decided whether 4 or 5)
• There is a teach pendant with touch screen( there will be no screen more), everything is going to be controlled by this screen
• The distance between screen and machine will be min. 2 meters.
• The machine is going to be used for welding in industrial environment.

Here is what I couldnt decide or have a reservations...

• If I will place Raspberry pi inside the teach pendant, there will be a 3 meters distance between I/Os and pi. So I have to use MESA board or Ethercat I/O board (I have never used any of them before) to combat with electronical parasits.
  • Negative side of using MESA board is there is no domestic dealers in Turkiye and if I wanted to buy externally there may be some problems with customs. If I overcome this problem, this card is ideal for me...
  • Negative side of using Ethercat I have no information in this world. In Turkiye I can easily find Beckhoff products and I think I have to use EK1100, EL1008 and EL2008 for my setups. But there is a big question for me, Can I drive stepper drivers with EL2008(digital output module) or Do I have to buy a EL7031 (motor controller) ?
    And as a similar question, Can I read an encoder with EL1008 or Do I have to buy EL5101 (encoder reader) ?
• If I will place Raspberry pi outside the teach pendant, there will be a 3 meters distance between the screen and pi. So I will use 3mt HDMI cable. On the I/O side I will use raspberry pi's GPIO pins. Do you think will this be a problem with 5 axis movement?

I know it is a little confusing but its same here ....
Can you offer me an another solution or Is my path correct?

A ethercat digital output card can not drive a stepper motor, it is too slow.
Best is to use an ethercat-integrated stepper motor driver, such as rtelligent ect60.
A really slow encoder (a few Hz) can possible be read with the EL1008. The EL510x is otherwise needed, especially for the arc voltage reading.

If you already have stepper motors and drivers, mesa is the best way. There is one card that has all functions needed.

I gave up working with ethercat because my setup needs to be cheap.
It gets expensive when the step driving involved...

I'm going to work with other two options...

Do you have any opinion about raspberry pi's gpio pins? Will I have any problems while working with 5 stepper motors?