Time to setup my lathe with 7i76e

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26 Dec 2017 19:19 #103705 by tecno
Yes I do have some laying around, always good to practice on.

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26 Dec 2017 19:20 #103706 by RotarySMP
What type of lathe is that?
Mark

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26 Dec 2017 19:25 #103708 by tecno
Mark, this an old Swedish CNC school lathe from late 90's

www.93x57r.se/tecno-cnc/images/CNC3000/O...NC3000%20images.html


Here the new gear to be installed when I am fit enough to do it.
www.93x57r.se/tecno-cnc/CNC3000.html

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26 Dec 2017 20:15 #103710 by RotarySMP
Lovely lathe. You are doing a great retrofit on it.
Mark

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26 Dec 2017 20:16 #103711 by tecno
Thanks

Happy Holidays

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27 Dec 2017 14:49 #103750 by tecno
Got some mail today from China, 2x 100ppr encoders.

Directly to 7i76e
Want to use 1 analog input for selection of steps/detent so is following resitor values OK 1K 10K 100K?

What if using a 100K potentiometer = usable or not?

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27 Dec 2017 15:47 #103753 by PCW
if you want to use a potentiometer for 7I76E analog inputs, 5K is a good choice

100K will work but will be quite non-linear. it will be correct at 0 and 100% but droop
significantly in the middle, that is at a 50% pot setting the analog reading will be around 15%.
This is because of the 22K load resistance of the 7I76E inputs

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27 Dec 2017 16:10 - 27 Dec 2017 16:10 #103755 by tecno
OK then 5K it is.

What is the pros and cons using pot versus selector switch?
Last edit: 27 Dec 2017 16:10 by tecno.

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27 Dec 2017 21:13 - 27 Dec 2017 21:13 #103764 by rodw
I think that the selector switch is a better option as thats what LinuxCNC expects. If you use a 4 position binary coded switch, you can do it with just 2 inputs. That gives you 3 scales plus an off position
# Metric units used
loadrt hm2_eth board_ip="10.10.10.10" config="firmware=hm2/7i76/7i76e.BIT num_encoders=1 num_pwmgens=0 num_stepgens=5  sserial_port_0=2xxxx" 

loadrt mux4 count=1
addf mux4.0 servo-thread
loadrt or2 count=4
addf or2.3  servo-thread

setp axis.x.jog-vel-mode 0
net x-jog-counter <=  hm2_7i76e.0.7i76.0.0.enc0.count
net x-jog-counter => axis.x.jog-counts
net mux-in1 or2.3.in0 <= hm2_7i76e.0.7i76.0.0.input-22 => mux4.0.sel0
net mux-in2 or2.3.in1 <= hm2_7i76e.0.7i76.0.0.input-21 => mux4.0.sel1
net x-jog-enable <= or2.3.out
net x-jog-enable => axis.x.jog-enable
setp mux4.0.in0 0.0
setp mux4.0.in1 1.0
setp mux4.0.in2 0.1
setp mux4.0.in3 0.01
net x-jog-scale mux4.0.out => axis.x.jog-scale
Last edit: 27 Dec 2017 21:13 by rodw.

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27 Dec 2017 21:57 #103765 by andypugh

I think that the selector switch is a better option as thats what LinuxCNC expects.


I think using a wafer switch and fixed resistors into an analogue input is fairly cunning. You can have several positions into a single IO pin.
The HAL side can be a set of wcomp components or a lincurve component with the output converted to integer.

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