Need help with Rotary position switch

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grossm5000
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08 Apr 2024 15:45 - 08 Apr 2024 17:51 #297819 by grossm5000

Need help with Rotary position switch was created by grossm5000

Good morning everyone.
I have a Fry ET18 lathe I am in the process of updating. I am using a Mesa 7i77 and 6i25 board. The lathe has rotary switches for both feed and speed overrides, which I would like to use. The problem is that I cannot find any documentation on the switches, and therefore dont know how to wire them into the Mesa
I attached the factory wiring diagram, and a few pictures of the switches. They are 15 position switches, have 5 wires coming out of them, and appear to be '4 deck' switches from what I can tell. The numbers on the back of the switches are C4D0115N-4471 and I think they are made by Electroswitch. The only documentation I was able to find is from Mouser (here is the link: www.mouser.com/datasheet/2/128/c4-2309149.pdf) but I still could make sense of how the wiring would work...with only 5 wires, how is it possible to make 15 different unique positions??? I am assuming at least one of the wires must be DC power?

Thanks folks!

EDIT:
I now believe it is possible to have 15 combinations with one pole and 4 outputs. I have attached that image as well.

Last edit: 08 Apr 2024 17:51 by grossm5000. Reason: Added rotary switch combination sheet

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PCW
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08 Apr 2024 16:11 #297821 by PCW

Replied by PCW on topic Need help with Rotary position switch

The switch is possibly binary encoded so there may be one common
connection and 4 outputs. Unless you have further details on the
switch, you will likely need to determine its operation with an
ohmmeter.

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andypugh
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08 Apr 2024 16:34 #297823 by andypugh

Replied by andypugh on topic Need help with Rotary position switch

The switches seem to be generic wafer switches, so as PCW says, you might need to figure out the wiring/encoding with a multimeter.

15 positions and 5 wires hints at binary encoding but it could be straight binary or gray-coded.

One wire will be common, and then others will be connected to that (probably through diodes) . If this is the case then you would need to set your multimeter to diode-check mode as the ususal voltage used to measure continuity is too low to overcome the forward voltage drop in diodes.

All you really need to do is figure out whether the common wire is a ground or a voltage. With the multimeter in voltage mode look for a wire that stays at a constant voltage WRT ground regardless of the position of the knob.

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andypugh
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08 Apr 2024 17:18 #297824 by andypugh

Replied by andypugh on topic Need help with Rotary position switch

andypugh wrote:
All you really need to do is figure out whether the common wire is a ground or a voltage. With the multimeter in voltage mode look for a wire that stays at a constant voltage WRT ground regardless of the position of the knob.

I meant to go on to say that, once the inputs are connected to inputs in LinuxCNC we can work out the encoding then.

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grossm5000
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08 Apr 2024 17:57 #297826 by grossm5000

Replied by grossm5000 on topic Need help with Rotary position switch

Sounds good. Ill start poking around with a multimeter this evening.

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rodw
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08 Apr 2024 23:44 #297835 by rodw

Replied by rodw on topic Need help with Rotary position switch

This may help
forum.linuxcnc.org/show-your-stuff/32029...build?start=20#85279

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grossm5000
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11 Apr 2024 01:05 #297978 by grossm5000

Replied by grossm5000 on topic Need help with Rotary position switch

Thanks rodw - I actually read that very post earlier.

I have not been able to do anything with a mulitmeter yet (kids) but I did notice a hint on the OEM wiring diagram - both the speed and the feed rotary switches are fed by (or connected to) 'TB1-9' on the original wiring. It would also appear that TB1-9 is a DC COM, which would lead me to think that the other wires on the rotary switch are NOT DC COMs.

Multimeter tomorrow.

The following user(s) said Thank You: rodw

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grossm5000
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11 Apr 2024 18:38 #298019 by grossm5000

Replied by grossm5000 on topic Need help with Rotary position switch

Ok guys, I've got it mapped out as shown in the attached picture. The common wires are in fact the grey and white wires. My plan is to supply 24VDC to the common wires and then plug in the other wires as inputs on the 7i77 board.