5i25 + 7i85s +....

Update:
COMMANDED also as ACTUAL position moves from 0 to 999.97x and 1000 to 0.02x

If it also has something to do with PID i guess ill figure it out.

[edit]
Im just stupid... -> unconected pid.x.feedback accidently. All fine now.

I understand now, why the software PID is needed.

The steps at a MESA setup are not precalculatet from position to position like in a stepper configuration.
Its a totally different way of movement.

I dont know, why i didnt realized that before.

Actually I'm pretty sure all of LinuxCNCs step generators work in a similar fashion, its just that the feedback mechanism
is hidden in the driver when you use position mode.

Thats what i see when i track the signals on my USB Oscylloscope.

It would be the same, if Axis sends Coordinates and MESA calculates the Step/Dir sequence.

The MESA card isnt able to know how many Steps are needed.
Axis just sends velocity and acceleration informations and recalculates it (PID) by the Feedback from the MESA card.

In Steppermode there is a perfeckt stable set of Step/Dir signals for a calculated move.
20 repeats and 20 times the same.

Im in a hard decision now... I compared my Servos in
- steppermode on LPT with 8.000steps/rev.
- and Servomode on MESA

-> Steppermode is way more accurat. And the Hardware PID inside the Drive does the rest.
-> Servomode gives me about 10 times more Speed.

Its like: digital is digital ... analog is analog.

Nope, that is quite false

With properly tuned PID the velocity mode stepgen is more accurate than the LPT system
(partly because its feed back works on fractions of a step in fact 1/65536s of a step)

If you use encoder feedback you will see larger errors (since your drive and its motion are not perfect)

Its easy to get better than 100 nm absolute pulse train accuracy with the Mesa stepgen at 30000 mm/m
this is impossible with the software stepgen

I was just hoping, you tell me something like that, so im able to get back on Track


I hooked up a Linearscale as Step/Dir source sraight to the Step/dir Imput of my Servodrive.
Then i measured the Scale on Chanel 1 and the Servo drives encoder output on Chanel 2.

I almost wasnt able to move the Scale fast enough, to get a difference of more then 0,2 Degree.
And we talk about 1-2m/sec so 60-120m/min.

This tells me, the hardware PID is unbeliveable fast.
But its useless as long as there are no straight "point to point" pulse informations.