2 pole 6 Position rotary switch for (2x) MPG enable and scale settings

Hello guys,

after i got the both MPGs to work properly, as well as some buttons like Start/Step and Pause/Resume, a potentiometer for controlling Feed and for my Lathe project i am currently stuck with the Scale selector switch. (2 Pole, 6 position: Aliexpress link ).

I have used the exacty same .hal settings as "Rodw" did in his Rods "Spaceship" Scratch built Plasma Cutter buildPlasma build
*I have changed "or2.3" to "or2.1", because i currently have only 2x or2

I connected PIN 3, 4, 6 and 8 together with one wire (please take a look at the picture) and connected PIN 8 to +24V, so all have +24V.
The A and B pin to input 21 and 22 on my Mesa 7i76E.
So, i think its exactly as Rodw did.

I have opened Halmeter, choosed pin "mux4.0.out" which shows "0" when the switch is turned completly to the left side, when moved one click to the right it shows "0,1mm", then next clicks always "0".
I dont understand why, i really tried to find the problem. For example i choosed other pins instead e.g. pin 6 and 8, but what i ones got was that i got 2 times 0.1mm, so i seems like its some kind of .hal config problem.

When i exchange the Pins in the below 2 lines (.input 21 will be on top, 22 on bottom), i get 1,00mm instead of 0.1mm, but all other show "0" on Halmeter.
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

When i play around with the position pins then i get e.g. (switch rotated from left to right/clockwise):
Position 1 : "0"
Position 2 : "1,00 mm"
Position 3 : "0"
Position 4 : "1,00 mm"

No matter how i change the pins i do get no other value than "0" or "1,00mm" (or 0,10 mm, when exchanging the input Pins)

I have replied to Rodw and he wrote that my Rotary switch might be not same as his, so i have to create a Truth table and check which pins are on/off on the 4 positions i need. I have tried to get some informations how to do that on youtube and google and i am pretty sure i understand it correctly and i have of course already tryed the wiring setup i thought its correct, but i still get no other Values than "0" and "1,00 mm".

Here are the table to show which pins are ON when on all 6 positions:
Position 1: A - 1 / B - 7
Position 2: A - 2 / B - 8
Position 3: A - 3 / B - 9
Position 4: A - 4 / B - 10
Position 5: A - 5 / B - 11
Position 6: A - 6 / B - 12
So, e.g. in Position 1, the Pole "A" is connected with "Pin 1" and Pole "B" with "Pin 7".

The Truth table should be as Rodw posted:
00
01
10
11

If i understand it correctly, in Position 1, Pole A and Pole B should be both on "false", so that the result is "00"
On Position 2, Pole A should be "false" and Pole B "true".
Position 3: Pole A should be "true" and Pole B "false"
Position 4: Pole A and B both "true".

If thats correct, then i should wire up those terminal Pins together and then to +24V: 3,4,8 & 10.
Short explation of my thinking :
When the switch is in Position 1, A1 and B7 should not get +24V, to get "00"
When the switch is in Position 2, A2 should not get +24V, but B8 should get +24V, to get "01"
When the switch is in Position 3: A3 should get +24V, but B9 should not get +24V, to get "10"
When the switch is in Position 4: A4 and B10 should get both +24V to get "11"

My explenation might be wrong and difficult to understand, but if so, please ignore it.

With this wiring setup i get this values on Halmeter Pin "mux4.0.out":
Position 1: 0
Position 2: 1 (1,00 mm)
Position 3: 0
Position 4: 1 (1,00 mm)


I somehow do not believe that my thinking is correct, just because its not working as it should, but also i somehow think that the .hal setup is not correct, because i am getting values on Halmeter, but not the correct one.
I checked also those pins "mux4.0.sel0" and "mux4.0.sel1" and found out that sel1 is always "FALSE"
Also i checked pins "or2.1.in0" and "or2.1.in1" and found out that .in1 is always "FALSE.
Thats the reason i am thinking that the hal setup is wrong, but it works for Rodw, so i am currently a bit confused.

Even if everything is wrong what i did, at least you see that i did try to get it done by my self.

I hope you can help me out. I have attached my mpg.HAL and my main .HAL.

Thanks in advance.

i opened it on yesterday, but i will do it now again and post a picture

Please take a look at the 3 pictures which shows the inner workings and on the third picture you see that wiring setup i had before.
(i marked with the black marker the position how the both parts fit together)
I hope those pictures help.

Its working!
Thanks a lot for letting me know that my wiring setup was correct and i should check the inputs.
I am not sure why it has not worked, because the outputs ( A and B ) where wired to the correct input terminals 21 and 22.
What i now did: I took them out of input 21 and 22 and put them in to input 8 and 9 and of course changed in my .hal the inputs to 8 and 9.
I opened Linuxcnc and the switch worked, but the scale order was a bit wrong:
Pos 1: 0
Pos 2: 0.1
Pos 3: 1.00 mm
Pos 4: 0.01 mm
So, i changed in the hal the order of the "setp mux4.0.in" lines and now the order is correct.

Thank you very much tommylight!
I am also very happy, because my thinking was correct when trying to get it done without help, but i just wasnt sure because it has not worked properly.
I learned something and got the motivation to learn more.

I wish you and all others a nice weekend

You are right.
I was something i knew earlier because i ones had this problem already, but please look at this picture from grabcad of the 7i76E on bottom (The inputs seem to be wrong, but when counting from the input 16 from TB6 and continue terminal TB5 to pin 22 then it seems to be the correct inputs)

Because of that picture i choosed Input 21 and 22. I am now a bit angry about my self, because i thought about it to change in the .hal to input 20 and 21 before i wrote the thread, but i dont know why i have not done it.. I could save your and my time, because that was the only reason why the switch/settings did not work properly.


EDIT: i edited the picture and marked the correct Pin names for the .HAL. This might help others in future so that they not get confused by the original picture which was not edited.

Sorry, now it is there.
I have edited the picture in Photoshop so thats it clear. The original picture is from Grabcad, here the link: grabcad.com/library/mesa-7i76e-7i76e-1

EDIT: i just thought about it if the reason for the wrong input pin numbers is because i have it in Serial mode 2 ?
In the standard mode the Pins 21 and 22 might be correct as on the grabcad picture.