AX58100

I already understood how to do that conversion.

That sdodataraw input field to sdoconfig isn't the easiest to use, unfortunately.
After using an online ieee float to hex converter one ends up with 0x43480000 for 200.0
Swap the byte order, the number becomes SdoDataRaw="00 00 48 43".

An alternative is to set the value outside of linuxcnc
ethercat -p 0 download 0x2001 0 200.0
and check the value with 
ethercat -p 0 upload 0x2001 0
The value needs to be set at every power cycle of the board, it isn't saved.

I gave MacAcceleration a default value of 1000000.0, you might want to give it a reasonable value.
 

It work now.

Good the hear, thanks for update.
The firmware needed an overhaul to get all info in and out anyways.

I found the limit in the software but it wasn't just to increase 16 PDOs to say 32 PDOs.
For the time being I consider 16 PDOs in and 16 PDOs out to be the max the number of PDOs the Ax58100 can handle.
It can be more, but my tests doesn't show that and I find no info in the pretty useless datasheet of the Ax58100.

Thanks for your support. One thing I'm still unsure about is the speed of each axis. On my PC, it's limited to a maximum of 30. If I set it higher in the INI, it causes a following error, and that's a limitation when using servomotors that can operate at higher speeds.

I could repeat that.
It was MaxAcceleration that had a too low value 1e6, now 1e8.
This only matters if one gets gravel sound from the motors.
Setting MaxAcceleration slightly above real max acceleration reduces that significantly.
Otherwise, there is no harm to set it very high. Set too low and it can't accelerate up to speed fast enough.
Pushed a commit, please update the eeprom. Firmware is the same.

I also added an axis_mm.ini config for metric units for testing.