Custom pendant connection to LinuxCNC

Hello...

I plan to make custom pendant for my new machine. Now I looking best way to connect to LinuxCnc.
As in pendant is small microcontroller I had few connection types.

Option 1 is to simulate Modbus and to be connected to serial port. The Linuxcxc part should be already written in classicleder.

Option 2 Is to serialy send/recceive data trought I/O pins. I need to write custom HAL hardware driver.

Option 3 is to use USB HID. - As machine is 7 meters long and pendant cable at leas 10 meters long I rule this out as its too long for USB.

Does someone know better way to do this? Or show me if I something miss somewhere?

Thanks...

andypugh wrote:

eslavko wrote:

Does someone know better way to do this?

Mesa 7i73? That is pretty much the task it is designed for.

I miss that.
Now I have my own design almost ready and I will use it. But have similar functions.
Just need to decide connection point to the host.
Serial port at 115200bps is capable to handle required troughput. But doesn't know if Modbus and lader logic works as should..

Actually I miss that userspace components are written in python. And they doesn't need to recompile LinuxCnc.
So I focus on plain RS232 to communicate to pendant. I will use own protocol as it will be quicker than something like modbus.
Actulay I need one way communication from pendant to linuxcnc and userspace py to split data to 5 encoders and 12 other keys that i have left for start/stop/pause.... whatever....
On the other side I can use 232 to show little DRO on pendant.