Hi. I am retrofiting a flatbed (around 5' x 3') plotter into a cnc router. I bought 4 gecko 340 and i intend to use the Mach software.
My DC motors are 24V 140w. They have 125 steps/rev encoders, but i plan to change with US Digital 500 steps/rev encoders.
The gear boxes are 1:20 reduction and at the end i use rails. 20 revs of the motor corespond to around 4 inches of travel.
Can anyone tell me what can be the max linear speed that can be achieved with Gecko/mach combination ?
Also what is the maximal (if there is a limit....?!) rev/min of the motor for the correct reading of the encoders (500 steps, 2 inch diameter) ?

Any help is appreciated. Thanks.

Lucas

You are limited to a 45Khz Step rate and that works out to about 1300RPM of the servo motor. You say there is a 2" Dia pulley driving so that works out to about 408IPM if you have a 20 to one reduction and the resolution is about .000157 per step... I would think about getting 250 count encoders and you will not have to stress the software and computer as much That will give you more IPM and the resolution will be about .000314 ish...

That was a nice break form the code Hope it is a help!
Brian

Brian, thanks for reply !

Can u explain this more: "You are limited to a 45Khz Step rate and that works out to about 1300RPM of the servo motor. "

I made my calculations as follow:
45Khz means 45.000 pulses/ second.

An encoder with 250cpr will give 1000 pulses/rev in quadruature.

45kz/1000=45 rev/ sec = 2700 rev/minute (rpm)

Next question: 45Khz of the Mach (called "Kernel"....don't know why...?) is for one axis or for alll axis

Sorry the calcs that I did at first were all based on the 500 line encoder

The 45KHz is per axis so you are okay...

Thanks a lot !