Aufschaukeln mit JMC iHSS60-36-30-21-38 in Verbindung mit Linear Encodern

tommylight wrote:

Jensner wrote:

Zur Signalverarbeitung kam eine 7i85s dazu und die 7i96s wurde mit der entsprechenden Firmware geflasht.
Nach etwas testen und Jumper setzen, erhalte ich nun auf allen 3 Achsen saubere Signale über die ersten 3 Encoder-Eingänge der 7i85s.

   
Are the encoders wired to Mesa 7i85S?
Or are the encoders wired to JMC ?
Or, i really hope not, did you remove the encoders from JMC and wired to Mesa? This will not work without changing the drive config so the JMC are set to work with no encoders.
I assume this is the case as you mention the motor moves slowly when enabled, and this is exactly what will happen when encoders are detached from JMC.

Yes, the 3 Linear-encoders are wired to the Encoder-Ports at the MESA 7i95s.
But the iHSS60 itself are Closed Loop and i thought, that the internal controller maybe tries to correct the position.
Than the linear-Encoder gets the signal to the PID to correct and this leads to the growing shaking. 
Do you know what i mean?

Has someone maybe a similar config? Closed Loop Stepper together with Linear-Encoder on Mesa?

tommylight wrote:

This will not work without changing the drive config so the JMC are set to work with no encoders.

Do you know how to config this in the JMC?
I did some investigation, but could not find how to do this...

If the scaling is correct, FF1 must be 1.0

I would lower the P term (till it no longer oscillates), raise the ferror limits
 And the plot the following error (and commanded velocity) to get an idea of
what is happening.

Another guess is that the drive responds too slowly to step commands
(this may be a tunable feature)

The link i posted, explicitly mentions making the machine work without encoder feedback to LinuxCNC first, so enable the stepgen feedback in the hal file and omit the encoder feedback, test the machine, set the scaling correctly, and only after getting this done activate the encoder feedback and omit the stepgen feedback.
Closed loop stepers when loop is closed on the drives are viewed as normal open loop steppers from LinuxCNC.
So yes, it should work with your drives, just make sure they work properly in open loop mode to LinuxCNC.

Added this to the link i posted here to better explain what can be used : Thank you for reminding me.
Danke schon.

tommylight wrote:

The link i posted, explicitly mentions making the machine work without encoder feedback to LinuxCNC first, so enable the stepgen feedback in the hal file and omit the encoder feedback, test the machine, set the scaling correctly, and only after getting this done activate the encoder feedback and omit the stepgen feedback.
Closed loop stepers when loop is closed on the drives are viewed as normal open loop steppers from LinuxCNC.
So yes, it should work with your drives, just make sure they work properly in open loop mode to LinuxCNC.

Thanks tommy,
so i will test it today.
hopefully this will work.
This was a lot of work adapting these linear-encoders and make all work, but it would be an extreme optimization of my machine to get it to the level of accuracy I always wanted. Not least to finally get a handle on the occasional step losses on the X-axis.

But with you all, i am sure. At the end this will work! ;o)