spindle encoder plus mpg 7i76

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03 Sep 2016 17:54 #79981 by calvin.d
on a 7i76
I have an mpg connected to the dedicated encoder input
The mpeg is 5v

I am going to add a spindle encode but I am not sure of what the best approach is
I have either 24v gear tooth sensors which i can use to count the teeth on the timing pulley on the spindle
but I would need to divide this out to get a single revolution pulse

or I can make an optical encoder disk

so i guess my questions are
1. can I use the encoder input section and gpio pins to run separate encoders at the same time
2. if I go the optical route, what is a good ppr for the encoder disk

Thank You for the help
Calvin

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03 Sep 2016 20:32 #79990 by cmorley
By using mode 2 you can have up to three encoders available at the same time.
one hi speed quadrature X4 encoder counter usually used for the spindle,
two hi speed quadrature X1 encoder counters usually used for MPGs

Others have had complete success with using regular GPIO and a software encoder counter for MPGs if needed.

I will say that if you ever want to do ridged tapping you will need quadrature detection with indexing on the spindle.
I'll let others advise about gear tooth detection.

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03 Sep 2016 21:17 #79992 by calvin.d
thanks this is exactly what I was looking for

so mode if i am understanding this, I should use the dedicated encode inputs for the spindle and the gpio for the mpg, the gpio pin options will show up once I switch to mode 2

Thank you for the help
Calvin

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04 Sep 2016 11:44 #80010 by andypugh

I have either 24v gear tooth sensors which i can use to count the teeth on the timing pulley on the spindle
but I would need to divide this out to get a single revolution pulse


I think that the 7i76 spindle encoder inputs might well be safe to 24V, but check the manual.
You probably want a separate index pulse too. That can be from a third sensor looking at any convenient feature on the spindle (such as a bolt head or keyway). On one of my machines I replaced a grub-screw with a headed alternative to provide an index.

NPN prox-switches can be connected to 5V inputs even if powered buy 24V as they basically act as a switch-to-gnd.

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07 Sep 2016 00:10 #80099 by calvin.d
ok can someone tell me how to change the encoder mode from inside of pncconf because I am looking and I am not finding it.

I am sure this will be very obvious once someone shows me it

Thanks for the help

C

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07 Sep 2016 00:48 #80101 by calvin.d
ah ok i found it

but when i made the change it did not actually show up in the config

i had to change
sserial_port_0=000xxx

to

sserial_port_0=200xxx

mpg is not working, not sure why going to attach the machine config in next post

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