Rotary Selector Switches & Resistors

PCW wrote:

As an aside, I am also a little confused why PCW suggested 00, 11, 01, 10, instead of 00, 01, 10, 11. It seems more logical to me to order it like legit binary, and it's not like it's harder to connect it this way.

The 4  --> 2 diode encoder circuit I posted is in binary order but you need to consider
that the 7I73 inputs have pullup resistors so are high when unconnected and low when
grounded through a diode so:

SWITCH POSITION
0  Grounds inputs 0,1 with CR1 and CR2 = 00b = 0d
1  Grounds input 1 with CR3 = 01b = 1d
2  Grounds input 0 with CR4 = 10b = 2d
3 No connect so = 11b = 3d
 

Can you recommend a source of information that can decode what you just said?

fully_defined wrote:

rodw wrote:

Not quite what I was looking for but something like this. SOme have stops that let you limit the number of positions
au.element14.com/lorlin/bcks1004/rotary-...MA-RECO-PDP-STM72189
 
In the US, this is all Digikey has that's coded for hexadecimal. My own personal lack of vocabulary for searching is also something I hope to improve as part of this conversation.

www.digikey.com/en/products/filter/rotar...AMqcAnAJYA7AOYgAvtKA

Me too! so I am hesitant to make a recommendation for that reason but I think that a 3 pole or 4 pole 12 position rotary switch also does what we want. eg decodes a position to a bit map on the poles.

I have seen those, but I have until now dismissed them as something weird that I don't understand the purpose of.

According to the C&K switches datasheet: www.ckswitches.com/media/1349/arotary.pdf, the increase in the number of poles corresponds to a decrease in the number of positions by a factor of the number of poles, with no further explanation. The schematic just looks like three or four separate switches with three or four positions each, and I don't know the use case for that. I was hoping to get a better explanation here, and it looks like we might be on to something.

Is it possible that this is the exact same thing as hexadecimal coded, just without using those words? And that I don't even need diodes?

rodw wrote:

fully_defined wrote:

rodw wrote:

Not quite what I was looking for but something like this. SOme have stops that let you limit the number of positions
au.element14.com/lorlin/bcks1004/rotary-...MA-RECO-PDP-STM72189
 
In the US, this is all Digikey has that's coded for hexadecimal. My own personal lack of vocabulary for searching is also something I hope to improve as part of this conversation.

www.digikey.com/en/products/filter/rotar...AMqcAnAJYA7AOYgAvtKA

Me too! so I am hesitant to make a recommendation for that reason but I think that a 3 pole or 4 pole 12 position rotary switch also does what we want. eg decodes a position to a bit map on the poles.
 

I found the datasheet for Lorlin switches, and I like what I see: lorlinelectronics.co.uk/wp-content/uploa...-ROTARY-April-24.pdf.

This seems to be what's available at Mouser here in the US: www.mouser.com/c/?q=Lorlin%20BCK, and I think that based on what limited information I see, I want BCK1006. I am assuming I can cut down the shaft.

I ordered 5.

 

looks perfect. Also seems terminal E is common to all of the positions. If so, connect 24v there. 

For example

0  Grounds inputs 0,1 with CR1 and CR2 = 00b = 0d

Means in the schematic i provided, switch position 0 grounds 7I73
inputs for bits 0 and 1 resulting in a binary code of 00 (00b) which is decimal 0 (0d)

The 7I73 input best suited to this use have pullup resistors
which means they will read high when unconnected. This is important
as it determines the switch connections.

And please please do not connect 24V anywhere near the 7I73...



 

PCW wrote:

For example

0  Grounds inputs 0,1 with CR1 and CR2 = 00b = 0d

Means in the schematic i provided, switch position 0 grounds 7I73
inputs for bits 0 and 1 resulting in a binary code of 00 (00b) which is decimal 0 (0d)

The 7I73 input best suited to this use have pullup resistors
which means the will read high when unconnected. This is important
as it determines the switch connections.

And please please do not connect 24V anywhere near the 7I73...
 

Thank you! I learn something new in every single line of this thread. In case it's not already obvious, I know what I want the end product (the control panel) to look like, but I know next to nothing about how to get there in LinuxCNC. Just wait until I start talking UI!

Roger that about the 24v - the 7i73 outputs 5v. I was mixing up two different concepts when I said 24v. I will correct that in the graphic, too, but more importantly I am going to use purpose-built binary switches, instead of building a binary switch from scratch.

Finally! you decide to follow the solution from the first reply you received in this thread!

 

rodw wrote:

Finally! you decide to follow the solution from the first reply you received in this thread!
 

Take better pictures.

I received the binary switches from Mouser today: www.mouser.com/ProductDetail/10BCK1006

Initially, I thought BCK1019 "code 042" was the right version, as it is true hexadecimal: 0-9, A-F; switch position 1 with all four bits as open circuits and position F as four closed circuits. Instead, I chose BCK1006 "code 033", which is 1-9, A-F + 0, and the bits are a mirror image. This means that all switch positions have at least one closed circuit, except switch position 16, which is four open circuits. No diodes necessary! Just +5v in to E (common), and out from ABCD.

Pos. 1: ABCD 1000
Pos. 2: ABCD 0100
Pos. 3: ABCD 1100
Pos. 4: ABCD 0010

My only concern (as of this writing) is the 0.26mm by 0.81mm pins. They are super delicate!