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Member
supersputnikk
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Accepted Solution

change encoder output from single end to be differential output

i have single-end encoder .how can do it ? change from single-end to be differential output .

thank you

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Buechsenschuetz
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Re: change encoder output from single end to be differential output

You have to add some circuitry. The IC AM26LS31 has TTL compatible inputs and RS485 compatible differential outputs which will be compatible with the UMI box. 

 

Using differential signals is recommended when you have long signal lines, the differential signal transmission is much less sensitive to environment noise. You should use twisted pair cables if possible. Of course the TTL-to-differential-signal-converter should be located as close as possible to the encoder.  

Member
supersputnikk
Posts: 16
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Re: change encoder output from single end to be differential output

Did i make it correct?

Do i have to connect resistor pull up ?

When I have to connect pull up resistor ?

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Buechsenschuetz
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Re: change encoder output from single end to be differential output

1. You have to connect the /G input to GND.

2. You mention the A channel only. The NI boards will accept signals from incremental encoders only, so there should be a B channel output on your encoder as well?? You can use the second half of the AM26LS31 to convert the B output signals.  

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supersputnikk
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Re: change encoder output from single end to be differential output

please explain principles of  brush servo control . How to control voltage at analog output(DAC CHANNEL) when i choose servo external commutation on axis configuration on MAX.

 

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Buechsenschuetz
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Re: change encoder output from single end to be differential output

oops ... should read "one more converter circuit contained in the AM26LS31" instead of "the second half". The AM26LS31 contains four converter circuits for TTL to RS485 signal conversion. 

 

There is no need for connecting unused inputs via pull-up resistors to +5VDC or directly to GND, the AM26LS31 has pull-up resistors on all inputs.  

Member
supersputnikk
Posts: 16
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Re: change encoder output from single end to be differential output

thank you very much