AASD chinese ac servo's step/dir Oscilations

Maybe I'm way off track here: I have no experience with step/dir drives, nor stepgen.

But I have EtherCAT drives where the position is sent directly to the drives. Step/dir should be equivalent in that you're basically modifying a position register in the drive? If so, why run the positon data through a pid regulator in the HAL file? Shouldn't the steps be sent directly to the drives? Maybe I'm interpreting the HAL file wrong, or it has something to do with how stepgen works?

This is not related to anything on the LinuxCNC side. The drives position mode needs tuning.

Chapter 9 in the aasd manual has an example of setting up position mode and shows the registers that may need adjustments.

Yes, I have tried everything. I cannot get it to bypass the internal pid. I think there is some settings missing or these drives are defective.
I have a 7i77 now installed.

I have done this before with these drives and they were a bitch to setup but I did get them setup with velocity control. The exact same drives, but these are not working. Probably going to have to fork out 3,000 and get some DYN4's from DMM-tech. I have used these before and they are a piece of cake to setup. the Chinese company is not responding to my emails. I'll have to take a hit on these. Its a hard hit.

PCW wrote:

Its not clear to me which parameters are which (and LinuxCNC doesnt need any PID changes,
this is all in the drive)

Does the drive come with any tuning software?

No it doesn't. The connector for connecting comm software is not on these drives.

I installed a 7i77 now and programmed the drives for velocity(speed) mode. Whatever I do with the pid it doesn't effect the motors.

I have a feeling I got duked........

The weird part is I can jog with the controls on the front panel of the drives and it works great.

I can run through the test of the initial inertia settings and it works perfectly and gives me the setting I should use for inertia,

Something is missing in the settings that I don't see in the manual to get it tp stop oscillating so violently. it does it in step/dir and velocity mode.

I cranked the P up to 2500 from 50 and it doesn't change like it should. It does have a very minor effect. So I am at a loss.

I cranked the P up to 2500 from 50 and it doesn't change like it should. It does have a very minor effect. So I am at a loss.

What term is P and what is D? I could not figure that out from the manual

Note that the tuning issue could be in their Velocity loop also so that
likely has to be tuned as well

Have you checked that "Automatic gain adjustment mode" isn't enabled (Pn258=1)?

According to page 196 in the manual, "8.3.2 Automatic gain adjustment", if you have Pn258 = 1 then "gain parameters such as Pn115, Pn116, Pn153~P156, Pn196, and Pn197 are not valid".

These seem to be the relevant parameters:

Pn045 - Gain switching selection (0-5, set to 0 for "Fixed first gain")
Pn257 - Load inertia ratio (0-100)
Pn258 - Gain adjustment mode (0-1, set to 0 for manual gain adjustment)
Pn196 - Torque filtering time constant (1-5000, unit 0.01 ms)
Pn153 - Speed loop gain (1-2000, unit 1 Hz)
Pn154 - Speed loop integral time constant (1-5000, unit 0.1 ms)
Pn115 - Position loop gain (1-2000, unit 1 Hz)
Pn184 - Speed feedback compensation

(There is no D component, but the manual suggests ways to combat jitter/vibration in section 8.3.4.)

What are these set to in your drives?