Re: [CAD_CAM_EDM_DRO] Re: Bridgport clone Retrofit

Bill Vance wrote:

>On Mon Nov 18 23:41:07 2002, marc_e_davis, <marc.davis@...> wrote:
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>>Jon
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>[snip]
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>>The encoders are already mounted to the back of the servos. I do
>>have some concerns here. There are 9 total wires coming from the
>>servos. I'm guessing 2 for motor power, two for encoder power, and
>>the rest for encoder signals. But it seems like a quad encoder would
>>only need 2 wires. I know come servos have tachs or something called
>>a resolver.
>>
>>
>
>Hi Marc;
>
>For encoders, as I understand it, there are 4, possibly 5 lines; An index
>signal, (not used on all systems), +V, ground, and a pair of quadrature signal
>lines. Unless, of course, you're talking about, "Phantom Power", (not normally
>used for CNC), in which case the number of lines would drop by one.
>
>

There are also differential encoders, which use 2 wires for each signal,
usually labeled
A and A- or A with bar over it
and
B and B-.

If it has an index channel, that would also have X and X-.

So, these encoders could have 6 or 8 wires, and may have a shield added,
for 7 or 9 wires
just on the encoder.

Jon