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Rotary switch - how to draw properly in chematic?

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Grossel

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Hi forum.

Have an switch with 12 connections, and there is 7 possible positions. It is taken from a small substation and had being used on the analog voltmeter to switch between meassuring L1-L2, L2-L3, L3-L1, L1-N, L2-N, L3-N and 0 (no connections between any poles).
It is pretty much the same as image of the rotary switch described on this page.

Using an ohm meter, I have made a simple table showing connected poles for different positions.

In left section, all numbers enclosed into a rectangle is what I hve defined as poles that are connected. So for example if the position of the switch is "L1-L2", then there are three groups of poles that are connected: pole 2 and 4, pole 3-7-9-11, and pole 1-5-9-10.
The three sub tables to the right is just me trying to see if that appears more easy to read - probably not.

My challenge is that I want to draw the switch into a chematic, but in a way so that it show the connections between the poles.

I do find a lot of images when google for "rotary switch symbol" but none of those drawings cover rotary switches that have groups of connections. If possible, I want to avoid using multi-color schematic, but only if possible.
 

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alec_t

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Ganging of switches is usually shown by dotted-line links between poles.
A test link
 
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Grossel

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Thank you. After reading a PDF as found in link I see I probably have missed the definition of a pole in rotary switch context - so what I ment to say in first post is that the switch mentioned have 12 terminals, not sure of the definition of a pole of a switch.

Ok, after reading some more figures, I think I've figured it out: one pole seems to be a common connection point, so that several terminals in turn will be connected to the pole, but not simoultaeous as the one I described in first post.

I'll try to draft and see if I can do one that actually make sense.
 

Grossel

Well-Known Member
No - I just doesn't get a working idea. The prblem I face is indeed that there is poles that - as oposed to the switches described in link above:
- Include 2 or more terminals
- has overlapping - since cluster of other terminals can be arranged/defined as poles.
So it may not be possible to make a simple (2D) schematic drawing that will also fit into a schematic, so that it reveals all possible internal connections of the switch.
 

JonSea

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Look for BCD (binary coded decimal) or Gray encoded rotary switches. They connect a number of terminals together in a particular pattern.

A BCD switch has one common termimal and 4 output terminals. Imagine the 4 output terminals pulled to ground with a resistor, and the common terminal connected to 5 volts.

At position 0, all output terminals are disconnected and you'd measure 0 on all terminals. You'd measure 0 0 0 0 on the terminals

At position 1, terminal 1 is connected to the common terminal and the others open. You'd measure 0 0 0 1 on the terminals.

Skip ahead to position 3. Terminals 1 and 2 are connected to the common, and you'd measure 0 0 1 1.

This type of switch is usually shown in a table.
 

Grossel

Well-Known Member
Thanks for input Jon Sea. I did think about making a logic table, but it comes to a stop (brain overload) because there is no such thing as multiple inputs and one output - in fact there is none terminals that I can say for sure (or pretend) being the input. But the approach was not a bad idea, just I not know yet how to set up the table - I doesn't want cell (ref. libre office calc) that contains a list of multiple terminal numbers - that job is done in the pdf attached to first post.
 

Grossel

Well-Known Member
So far this is how I'm getting so far:
So I figured - it must be all about grouping so most connections can be draw as an arc without having "jumpers". Also I diskovered an error in the original meassurement - for the switch position "L1-L2" terminal 9 occur two times, which is impossible.

Anyway - seems that I need to have one whole sector for each switch position (pretending there is no error - need to correct that before I draw further).

If you look at the pdf files, You can see how I have grouped the terminals according to what other terminals they are most likely to connect to at any given switch position.

The thing I have some doubt about if this will make it possible to read for anyone that haven't see the switch before. And also if the drawing eventually will be too complex to getting an overview of.

[edit]
The label for switch position is of course wrong - I just figure it take less time to just write a note (edit post) rather than fix the drawing.


Any thaughts ?
 

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