Help needed to get my 7i76E + 7i85S + 7i73 on my mill going.

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9 years 2 months ago #96837 by andypugh
Replied by andypugh on topic Help needed to get my 7i76E + 7i85S + 7i73 on my mill going.
This sounds like fun...

You have a system that is like a combination of my lathe and my mill. My mill has a manual 8-speed gearbox and my mill has an electrically-controlled 2-speed gearbox.

During milling operations the spindle speed tends to remain constant (unlike with a lathe in CSS mode).
Also, you should be able to change your motor speed with the spindle running? (I do not do this with my lathe).

On the mill the system uses the ratio of the motor speed to the spindle speed to detect the engaged gear:
forum.linuxcnc.org/47-hal-examples/27071...tection?limitstart=0

My lathe uses a custom HAL component to choose the spindle speed depending on speed command range.
(I don't think I have that on the forum)

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9 years 2 months ago #96838 by tecno
Replied by tecno on topic Help needed to get my 7i76E + 7i85S + 7i73 on my mill going.
Yes it is ;)

One way to get me going is to setp hm2_7i76e.0.7i76.0.0.output-15 TRUE until I get all things solved with the gearbox position readout.

I never change Hi/Lo on the fly. In my earlier Kflop we did read S command and switch Hi/Lo before starting spindle.

So how to do with these numbers?
setp hm2_7i76e.0.7i76.0.0.spinout-scalemax 2500 is the new max in Hi rpm on motor and Shifter Out Geears set to A
What if it will not go to 2500 do I just add untill I am satisfied? Does these added numbers do anything unwanted for future sync motion?

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9 years 2 months ago #96839 by andypugh
Replied by andypugh on topic Help needed to get my 7i76E + 7i85S + 7i73 on my mill going.

tecno wrote: So how to do with these numbers?
setp hm2_7i76e.0.7i76.0.0.spinout-scalemax 2500 is the new max in Hi rpm on motor and Shifter Out Geears set to A
What if it will not go to 2500 do I just add untill I am satisfied? Does these added numbers do anything unwanted for future sync motion?


What you need to do in this case is to consider the spinout number to be a _motor_ speed request and to calculate the motor speed required on the basis of the engaged gear. In fact, as you have a 2-speed motor you might even want to consider it to be a VFD frequency request.

The problem with my gear-detection system is that it can only work with the spindle turning. So automatic motor speed changes would need to happen with the spindle turning too.

However it is probably a _very_ bad idea to switch motor speeds with the VFD powered up. They don't like that.

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9 years 2 months ago #96842 by andypugh
Replied by andypugh on topic Help needed to get my 7i76E + 7i85S + 7i73 on my mill going.
Advice on the internet is to wire a constant-torque 2-speed motor as high-speed only and let the VFD handle all speed changes.

Your motor appears to be a constant-power motor, so it probably is worth keeping the 2-speed operation.

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9 years 2 months ago #96843 by tecno
Replied by tecno on topic Help needed to get my 7i76E + 7i85S + 7i73 on my mill going.
I am all ears on this subject, what I have learned it is called Dahlander type 2-speed motor.

So I assume what you are saying is constant-torque can withstand a wide rpm range as the cooling is good to do so.

My constant-power need to be handled as built to keep cooling etc under control.
Where did you find data saying this is constant-power type?

This is howe the motor is placed inside the Y axis boom

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9 years 2 months ago #96846 by tecno
Replied by tecno on topic Help needed to get my 7i76E + 7i85S + 7i73 on my mill going.
Here my truth table for the gearbox.

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9 years 2 months ago #96852 by andypugh
Replied by andypugh on topic Help needed to get my 7i76E + 7i85S + 7i73 on my mill going.
If you have sensors then it's all rather easier and motor-speed selection can be made before the spindle starts.

This HAL component that I wrote some years ago should be a good start.

It doesn't handle the 2-speed motor case, but that should be a fairly simple modification.

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9 years 2 months ago #96854 by tecno
Replied by tecno on topic Help needed to get my 7i76E + 7i85S + 7i73 on my mill going.
No sensors yet other than good candidates somewhere on a shelf ;) Need to build the mechanics first, may very well be 3D printed in ABS. But that is for later on.

Now that I have spindle more or less sorted out I need to get my axis motor parameters tuned in.

forum.linuxcnc.org/39-pncconf/33069-help...going?start=40#96623

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9 years 2 months ago #96860 by rodw
Replied by rodw on topic Help needed to get my 7i76E + 7i85S + 7i73 on my mill going.
If you are going to use sensors per your truth table, you could use a MUX8 component and a select8 component. I have used this for 6 axis selection on my pendant. (but I only use 3 xes at this stage. Don't forget the loadrt and addf statements
Code:
#Axis Select (0=off, 1=x, 2=z, 3=y, na, 5=6, 6=4, 7=5) setp mux8.0.in0 0 setp mux8.0.in1 1 setp mux8.0.in2 2 setp mux8.0.in3 3 setp mux8.0.in4 4 setp mux8.0.in5 5 setp mux8.0.in6 6 setp mux8.0.in7 7 net mux8-sel0 <= hm2_7i76e.0.7i76.0.0.input-23 net mux8-sel1 <= hm2_7i76e.0.7i76.0.0.input-24 net mux8-sel2 <= hm2_7i76e.0.7i76.0.0.input-25 net mux8-sel0 => mux8.0.sel0 net mux8-sel1 => mux8.0.sel1 net mux8-sel2 => mux8.0.sel2 net mux-float conv-float-s32.1.in <= mux8.0.out net mux-s32 <= conv-float-s32.1.out net mux-s32 => select8.0.sel net axis-select-x <= select8.0.out1 net axis-select-y <= select8.0.out3 net axis-select-z <= select8.0.out2 net axis-select-4 <= select8.0.out6 net axis-select-5 <= select8.0.out7 net axis-select-6 <= select8.0.out5 net axis-select-x => axis.x.jog-enable net axis-select-y => axis.y.jog-enable net axis-select-z => axis.z.jog-enable

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9 years 2 months ago #96861 by tecno
Replied by tecno on topic Help needed to get my 7i76E + 7i85S + 7i73 on my mill going.
Hi Rod,
looks interesting will take a closer look when it is time to implement this.

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