Gecko with motor question

[DESERT RAT]

Hello Everyone

Great news. It is allive. I now have cumputer control on all axis'. I drug the whole family out to show them it moving at my command. They think I am nuts.
However, I can only ramp up to about 70% of my max speed before it misses steps, even when the motors are turning free. I am pretty sure this is because I only have a 30v power supply instead of the 48v planned.
My motors do not have a max rmp rating on them but on their power curve chart it shows that they have 125oz/in at 4 thousand full steps a second. I am using Gecko 201's so I have 10 micro steps.
Does anyone know if the motors counting counting 4K full steps means it will turn 40k micro-steps? Or, does this mean it is actually counting each micr-step as a full step and therefore it has 125oz/in at 4k micro -steps/sec and may not even turn my required 20k micro-steps/sec to reach my max speed?
My motors are IH34110's from MCG and my max speed is defined by the amount of unsupported length of my ball-screw.

Thanks for any input
Rich

[Evodyne]

Each pulse you output equals one microstep. So your overall pulse rate needs to be ten times faster to get the same speed you would achieve if you were not microstepping. Without the microstepping you'd be faster, but less smooth.

I don't remember exactly, but the power supply voltage can range from 24 to 80 volts and should be 5 to 20 times the motors rated voltage (so long as it stays below 80 v). The higher the voltage, the better the high speed performance when microstepping. I believe these are the correct numbers. So yes, I would agree with you that you high end performance will be better when you go to your higher voltage supply.

[freak_brain]

I don't know the answers to your questions but your comments in the first three sentences was funny.

[Torsten]

Originally Posted by DESERT RAT My motors do not have a max rmp rating on them but on their power curve chart it shows that they have 125oz/in at 4 thousand full steps a second. I am using Gecko 201's so I have 10 micro steps.

If these are 200 steps per rev motor's than
4000/200=20 rev per second
20 x 60 = 1200 RPM

Microstepping would not change the torque much at this speed
but you would have to send out 40K pulses to drive it
at this speed.

[DESERT RAT]

Torsten
Thank you, you are right on but what I was wondering is when they say 4000 full steps per sec, they do not know that I am using micro-steps and maybe my microsteps might be counted as a full step.

2000 micro-steps= 1 rev

4000 steps per sec/2000=2 revs per sec

2 x 60 sec = 120 rpm

I am shooting for about 600 rpm and am just wondering if I am trying to exceed the max rpm of the motor. I am going to contact the manufacturer to find the max rpm. It is all for curiosity, to try and understand what they are really saying. 70 percent of the 600 rpm seems ok for now.

You should have the celebration afterwords. Good thing I couldn't find fireworks.

Thanks All
Rich

[arvidb]

Ten micro steps count as one full step. So you get the 125 oz-in at 4000 full steps/s or at 40000 microsteps/s.

"4000 steps per sec/2000=2 revs per sec"
The error here is you divide full steps by micro steps. It should read: 4000 steps per s / 200 steps [=2000 microsteps] = 20 rev/s.

Arvid

[DESERT RAT]

Thank You Arvid. That is what I assumed but I figured I better not assume. Time to upgrade the power supplies.


Thanks
Rich