7i77 and single ended MPG-Wheel encod er - read-out problem

Yeah, those are not valid levels, the LM393 should have outputs
very close to ground (< 0.5V) when low.

You might try cleaning the LEDs and sensors or adjusting
the threshold if there's a potentiometer on board.

Hello Together,

I tried to clean the LEDs and Sensor, but no real success. The peak levels are slightly higher now.
If I meassure with the scope between A and B (S0 and S90), I have pretty nice quaddrature peaks (with at least 5V peak-peak) - so its maybe a 2-wire differential encoder?
I tried to wire both to "A" and jumpered as differential encoder on 7i77, but still no success.

Now I rewired the other Inputs of the 7i77 and can use Input 16-19 for the MPG encoder. I rewired A and B (S0 and S90) to these connections allready.

Also, I changed the software- mode to mode 3 by [...] sserial_port_0=003xxx[...].

But I'm not sure, how to wire Input 16 and 17 in HAL.
I found another thread " How to wire MPG on 7i77 " but I'm not really sure, how to use the file there.
I use the PNCconfig- generated MPG-file right now and it seems to work well (according to HALshow) except the encoder.
So maybe you can help me to wire Input 16 and 17 to the PNCconfig  generated MPG section.

Thank you very much in advance and best regards,
Simon


 

Unfortunately if you don't have full A and B signal swings
the MPG inputs will not work either. There is something
wrong with your MPG dial if it does not output at least
TTL compatible signal levels (less than 0.8V for low and
greater than 2.4V for high)

... and I meassured again:

"normal position":
GND - S0: ca. 200mV
GND - S90: 4.06V

"Between normal" (between slots):
GND - S0: 4.06V
GND - S90: ca. 200mV

So S90 is 90° before/ after S0.

But then it should be a single ended encoder with S0=A and S90=B , isn't it ?
I don't know, what I meassured with my scope... maybe, I shouln't believe in its voltage-values
The above mentioned Voltages are meassured with an "normal" multimeter.

OK those are good values on S0 ( A )
the next question is does S90 ( B ) go low
at some position?
( This would be expected to happen about
1/2 way between the "normal" and "between normal"
positions )

hm... you mean B (S90) shoud behave like: 200mV - 0V - 4.06V while turning ?
I'll try to figure it out tomorrow. Right now, it seems to me, that it just "jumps" from200mV to 4.06V - the same for A (S0) just in opposite way

Edit: I just saw my stupid typo in my last post!
It should be:

"Between normal" (between slots):
GND - S0: 4.06V
GND - S90: ca. 200 mV

I'll try to edit my last post...