Using 7c81 with 5v encoder on bob3 config

Hi, 

Please can you share a bit file where i can use 5v encoder inputs on my bob P7 for my 7c81 board. I donot want to use 24v but 5v as a quad encoder fast inputs. Rest pins are fine for a normal 5axis bob3 pins.

thanks

You should be able to use single ended encoder pins directly with a 5V encoder.
The 5abobx3d configuration has encoders on all connectors and the 5abobx2
configuration has encoders on both connectors.

For more input protection, I  would add a say 100 ohm series resistor
to the encoder signal lines.
 

Thanks for your reply. But the cheap Chinese boards require 24v power supply to energize its inputs. So inputs are all not responding to 5v input of the encoder. Kindly help as how to wire the 5v inputs with 7c81.

I was suggesting wiring the encoder directly to the 7C81 pins
on a different 7C81 connector than the BOB.

(with series 100 Ohm resistors for protection from negative voltage spikes)

As suggested ,have linked pin to my 7c81 input. Its a single phase encoder. I have set the counter mode to 1. But the values are coming between 1.8v and 5v on my meter. The rawcounts are changing to 1 and then 0. Please help as the encoder is not reading any counts and not changing at all.

A 1.8V low level is not valid for a 5V single ended encoder output
Maximum low level for TTL signals is 0.8V

This may be a wiring error or similar.

Hi
Wiring looks ok to me. Please guide for the below points if they can help
a. Should I decrease the input voltage to 3 V. Will that help?
b. Should I decrease the output voltage of the encoder using a divider?
c. Perhaps changing the below values?
setp    hm2_7c81.0.encoder.00.counter-mode 1
setp    hm2_7c81.0.encoder.00.filter 0
setp    hm2_7c81.0.encoder.00.index-invert 0
setp    hm2_7c81.0.encoder.00.index-mask 0
setp    hm2_7c81.0.encoder.00.index-mask-invert 0

That looks OK but unless the low level signal is < 0.8V it cannot work.

That is, this is a hardware/interfacing issue.

The 7C81 inputs are fine with 5V signals but 1.8V is an indeterminate level
for the TTL level signals that the 7C81 expects

Do you have a data sheet for the encoder?