Looking for different communication possibilities.

Hi all, I need to interface LCNC (pre 2. to 4 big winches with non trivial kins (something similar to a spidercam..).
Those winches are moved by big servo motors (between 1,5 and 2,5kW), but they still don't have the driver part. the company who is building those winches is going to buy inverters/plc in these days, and I need to know eventual suggestions to interface with LinuxCNC.
Do you have some advice on what protocol to use?
- is Step/Dir a possibility?
- is it possible using some ModBus/CanBus to drive in realtime such a kinematic?
- maybe ethernet?
- is there any other performing communication usual in Industrial CNC which can be implemented in LinuxCNC?

Thanks for any advice.
Davide.

Yes, step/dir is a posibility.
Yes you can use modbus to control VFD, i doubt it can do any kins and i read that it is a userspace component, not realtime.
Ethernet can be used with Mesa cards or Beckhoff devices, have a look at ethercat.
Parallel port is an option, realtime, can controll machines easily but limited for IO, 12 outputs and 5 inputs per port, adding add on PCI cards is also possible. It can control step/dir drives, do PWM, used for 5 inputs ( 9 inputs in X mode, limiting ouptuts to 8 ). In most cases can do up to 20.000 pulses per second, some computers will do more ( i have an older xeon workstation that does 50.000 easily ).
Usualy winches are not very diferent from CNC machines as they do forward/backward, left/right and up/down. Using Linuxcnc to controll it, it becomes a huge pick and place machine. Hmmm nice idea.

I've spoken with the seller, and the inverter is a Rexroth hcs02. They can put in different modules to communicate. Now there's a simple 0-10v to control position, just to setup the machine.the seller suggest using profibus. Is there already made drivers for this bus? He says profibus is the most performing on this inverter as fast as 500uS per transmission, which i think is enough. The winches are going to move not more than 100cm/s with a 1/25 reduction and 50cm diameter drum. He also spoke about ethercat, but less performing.
The winch is going to have an on-board plc to manipulate a bunch of security sensors (belts, load, brakes, temp, current and 2 couple of endstops) and (i think) the pc is going to communicate with the plc.
I really don't know if its going to work with Lcnc or if I have to code a new software to make them run...
So let's face one step. What about profibus? In case I have to write a new driver, how they are written for lcnc? Python? Is there any example/codelines to follow?

Thanks you for helping..

I think writing a Profibus driver would be too much work.
0-10V _position_ control is also a bad idea, but +/-10V _velocity_ control with encoder feedback and a position loop closed in LinuxCNC would work well.

There is an existing profibus _userspace_ driver for LinuxCNC, but that would not be suitable for motion-control because it is userspace (nothing that uses Python will work in the realtime layer).

Is CAN bus an option? General Mechatronics seem to be well set up for LinuxCNC + CAN

Do Mesa have such a board? I mean -10+10 vel and enc in?

I think CanBus can be a possibility. But for what I know Canbus is not implemented same way from every productor. (I mean different data on different packets) Is the LCNC driver open to be corrected in case? So canbus is not run in userspace?
Thanks for the info.

dab77 wrote: Do Mesa have such a board? I mean -10+10 vel and enc in?

Several of them. From the classic 7i33TA to the 7i77.

I think CanBus can be a possibility. But for what I know Canbus is not implemented same way from every productor. (I mean different data on different packets) Is the LCNC driver open to be corrected in case?

I don't know, I have never tried to use a General Mechatronics card.