Freqmod.o vs Stepper.o

["antonio_ximenez" <antonio_ximenez-at-hotmail.com>]

I get the system working (Thanks again Ray) with MAX_VELOCITY = 66 mm/s ( in user units).

Let say:

I want to make rapids in range 2500mm/min.

My Hard:

I have a 5mm pitch leadscrew, and my motor give up in half step mode 360 steps = 1 rev. 

Computer is a PII 233 , 32 Mgas


My Soft:

EMC 2.2.16, kernel 2.2.18 patched with rtlinux 3.0

My Reasoning.

Let suppose

Parallel port is able to give up 12000 Hz/s or 12000 steps/s, if my machine has 3 axis

12000 Hz/s / 3 = 4000 Hz/s per axis. 

Rev/s

4000Hz/s / 360 = 11,11 rev/s

Travel in 1 second

11,11rev/s * 5 mm = 55mm/s 

Time in order to get the long travel (2500mm)

2500mm/55mm/s= 45,45 s . Much better than above asumption.

OK, I know, it would be a little bit more due at accel parameter.

1 ) Is it possible dont get ragged pulses at this feed rate ?

2) I have read that a 486/66 MHZ is able to give up 28800Hz/s 

3) Is there any parameter in order to define the spacing between pulses ? For example 50 microseconds.

4)Could I get the same rate than above with a microstep drive. For example a G201 in resolution mode = 10.

I think no. We will need a hardware step pulse generator or an advanced driver as G210.

5) How may steps is stepper.o able to give in order to donīt get ragged pulses ?

Freq.o

I am trying freqmod.o, but the MAX_VELOCITY that I am getting is 8 mm/s. I have tried in a PII 333 Mhz but the MAX_VELOCITY=12 mm/s. Is possible such different between stepper.o and freqmod.o. 

Is possible in a PII 233 get MAX_VELOCITY = 44 mm/s.

When we might use freq.o vs stepper.o ?





Thank in advance