Can I control my Gecko 201 drives with an automation direct (Koyo) DL05 or DL06 PLC?

Yes you can,

You have two options, if you use the native counter outputs (see pulse output settings), the output is maxed at 6k I think.

Option two is you can buy a HCTRIO (high speed counter module). This will output and input pulse streams at much higher rates.

Currently, I run an Independant ATC function from the PLC, so it dosesnt tie up any of machs movement axis.

Scott

I didn't think you could control your axis pulse stream through modbus,  this is a serial interface that has a limited throughput time. 

I thought mach would only control the axis pulse stream through the parallel port , ncpod, galil, or grex.

Your question was: "Can I control my Gecko 201 drives with an automation direct (Koyo) DL05 or DL06 PLC?" The answer to that question is yes.

Now if you want to control a stepper through a PLC that is controlled by Mach thourgh the mod-bus that is a different question.

You can't practically send a Machining axis through the mod bus. BUT, you can send movements for positional steppers/servos through the mod bus to the plc for positioning things like ATC's, bar pullers, spindle speed or other moter controls.

Scott