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

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25 Dec 2017 09:39 #103586 by tecno
Hi Rod, thanks.
a new output pin "gearbox2.speedratio" you can use to set the pid FF0 as per Andy's suggestions. = I am lost how this works.

I hope you will have a nice Christmas day.

Cheers
Bengt

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25 Dec 2017 12:27 #103588 by rodw

Hi Rod, thanks.
a new output pin "gearbox2.speedratio" you can use to set the pid FF0 as per Andy's suggestions. = I am lost how this works.

I hope you will have a nice Christmas day.

Cheers
Bengt


All I've done is extend the component to incorporate the maths Andy has suggested to keep your hal file tidy.
Use the gearbox2 component instead of the earlier one I provided.

Your max RPM seems to be 2500 rpm from your spreadsheet so I think it would look like this in addition to the hal code I published.
setp gearbox2.maxrpm 2500
net gbox-ratio <= gearbox2.speedratio
net gbox-ratio => <your-spindle-ff0-pin>
Substitute the correct hal pin for ff0 as discussed in Andy's last thread. This is what he said

PID output is partly made up of FF0 * input. So just setting FF0 of the PID for each gear might have the desired effect.

I would be tempted to scale the spindle control voltage to motor speed. Assuming a 1500 rpm motor then the parameter you want out of the component is 1500/max_speed for each gear (rather than the actual top speed) then link that to the PID FF0 pin.


If this works, it could be quite a handy template for a machine with a gearbox

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25 Dec 2017 12:52 #103589 by tecno
Hi Rod,
Nameplate says 2500rpm but in reality just now ~2400rpm (still needs some tweaking obviously)

net gbox-ratio => <your-spindle-ff0-pin> sorry but I do not know what pin that is.

I think we will get there with Andys help.

Cheers

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25 Dec 2017 20:59 #103599 by rodw
In your hal file you have
#*******************
#  SPINDLE S
#*******************

setp   pid.s.Pgain     [SPINDLE_9]P
setp   pid.s.Igain     [SPINDLE_9]I
setp   pid.s.Dgain     [SPINDLE_9]D
setp   pid.s.bias      [SPINDLE_9]BIAS
setp   pid.s.FF0       [SPINDLE_9]FF0
setp   pid.s.FF1       [SPINDLE_9]FF1
setp   pid.s.FF2       [SPINDLE_9]FF2
setp   pid.s.deadband  [SPINDLE_9]DEADBAND
setp   pid.s.maxoutput [SPINDLE_9]MAX_OUTPUT
setp   pid.s.error-previous-target true

net spindle-index-enable  <=> pid.s.index-enable
net spindle-enable        =>  pid.s.enable
net spindle-vel-cmd-rpm     => pid.s.command
net spindle-vel-fb-rpm      => pid.s.feedback
net spindle-output        <=  pid.s.output

I think again you are going to be caught here as pid.s.FF0 is a parameter so it can't be changed. Maybe Andy will have a solution.

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25 Dec 2017 22:15 #103600 by PCW
All PID tuning parameters are pins so can be connected to signals and updated dynamically

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25 Dec 2017 22:23 #103601 by rodw

All PID tuning parameters are pins so can be connected to signals and updated dynamically


Peter, thats not what the 2.7 docs say
linuxcnc.org/docs/2.7/html/hal/rtcomps.html#_pid
"The PID gains, limits, and other tunable features of the loop are implemented as parameters."

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25 Dec 2017 22:30 - 25 Dec 2017 22:42 #103603 by PCW
Take a look at the PID manpage, the html documentation is out of date.
Last edit: 25 Dec 2017 22:42 by PCW.

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25 Dec 2017 23:55 #103611 by rodw

Take a look at the PID manpage, the html documentation is out of date.


In that case Bengt needs to change
setp   pid.s.FF0       [SPINDLE_9]FF0
to
setp gearbox2.maxrpm 2500
net gbox-ratio <= gearbox2.speedratio
net gbox-ratio =>  pid.s.FF0

where 2500 is the correct top speed for his device

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04 Aug 2018 10:17 #115597 by tecno
Time flies and a lot of water has flown under the bridges :)

I have been looking at this to simplify S commanded speed to settings needed. VFD to control min to max in each gear setting
This VFD range is 40% of max and as I see it will not affect the torque very much so this is the way to get this mill going.

So in short it should be like this.

GearShift Hi
Gear A 1501 to 2500 rpm
Gear B 1251 to 1500 rpm

GearShift Lo
Gear A 751 to 1250
Gear B 451 to 750
Gear C 271 to 450
Gear D 161 to 270
Gear E 80 to 160


To be honest I have not tried the comp files due to my health reasons etc.. but would like to get back on the horse again and get this rpm control to work.

Is the comp still valid or any other solution?

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08 Aug 2018 07:28 #115793 by tecno
Can anybody give me a hint on what to do next?

I think that above new *table* of gear handling may need changes in gearcomp2 ?

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