1.2106 Back off bug with slaves

[jvalencia]

I recently installed 1.2106 for the back off feature.

I have the Y axis on a master-slave configuration and from what I've seen, the back off only applies to the master.

To get the slave to back off I had to edit its own configuration. I suppose this is wrong since both should be doing back off according to the master.

Apart from this bug (?), I think, a good feature would be disabling the fields that can't be edited when an axis is a slave, just for clarity.

[ger21]

I suppose this is wrong since both should be doing back off according to the master.

No, it's not a bug.
They should back off separate amounts, so this feature can be used to square a gantry during homing, by adjusting one side or the other's backoff amount.

[jvalencia]

ahm, then it's somewhat chaotic right now, isn't it?.

I mean, what options do still affect the slave axis? Fields that won't have an effect on a slave should be greyed out, so if "Back Off Distance" is active, you know you have to configure it. That's an easy fix to this "issue".

I could have damaged the bridge. I expected the slave to do exactly what the master did but it was not the case.

Luckily my back-off distance was just 3mm and nothing happened

[ger21]

I've always assumed that the user should set all settings the same for both the master and slave axis.
I don't know if UCCNC will automatically use the master settings for the slave axis.

[beefy]

Although perhaps not the norm, it is possible that master and slave could be using different drive setups (stepper pulses per revolution, gear ratio, etc).

Having both of them individually configurable can allow for this.

I guess the main lesson here is do not assume anything. Don't know is this is all explained in the user manual but it would be a good amendment if it's not.

[spumco]

At least in my case, UCCNC sets velocity, accel, and backlash settings the same for the slave. Even when I entered different info it was over-written on "save."

The backoff distance can be set different, and I think the homing up/down speed too - for the reasons Gerry mentioned. That way the home switches don't have to be set with any sort of precision, yet the homing process can still force the gantry square.

As Keith mentioned, there are other things that affect the master/slave drive relationships outside of UCCNC's control. In my case the PID settings in the stepper drive were different. Everything else was the same, but the slave was noticeably lagging behind the master. Since the motor feedback isn't sent to UCCNC it didn't matter that everything else was identical.

-Ralph

[jvalencia]

So as I see it, there is a lot of confusion with the master-slave parameters.

I think the UI should be improved as I suggested in this thread already.

Nobody really knows what fields are master-slave and what are slave-only. It should be clear when you configure it IMHO.

[ger21]

I don't see any confusion, but maybe that's because of my famiiarity with Mach3.

You MUST set all of the Slave settings yourself, and these settings need to match the master:
Steps/Unit
Acceleration
Velocity
Homing Speed

If any of these are different, I don't know what would happen.
But as long as they are the same, everything should work fine.

[Robertspark]

Just set them all the same, why add complexity for little gain with requesting the text boxes to be grey'd out and the software copying data across.

Lets face it.... you only set it up once per machine...

There are more important features that users would like and use way more than the setup which is quick, clean and simplistic at present.

[jvalencia]

I don't see any confusion, but maybe that's because of my famiiarity with Mach3.

You MUST set all of the Slave settings yourself, and these settings need to match the master:
Steps/Unit
Acceleration
Velocity
Homing Speed

If any of these are different, I don't know what would happen.
But as long as they are the same, everything should work fine.

That's not how it works right now. Some master settings will ovewrite slave settings. There is a lack of indication on what are those settings though.