My 7i76e Connection Sheet

OK, my education continues. I think I'm vaguely starting to get it. I have my inputs configured like the diagram from the OP's Connection Sheet -- with one difference: my sensor is N.O., where his is N.C. Each of my 8 leads go into pins 4-12 on the 7i76e's TB6 connector.

On their way to the input pin, each signal lead gets a T-spliced connection to the +24v side of the power supply through a 2k 1w resistor -- but I'm not sure how this matters, since the sensor itself feeds +24v straight through on it's black wire when it is open. When it detects nearby metal, the +24v toggles to Ground on the black wire. The net is, if I measure voltage on the input pins via their screw heads, that voltage is always +24v while the sensor detects nothing.

Is +24v going into the TB6 input pins OK?

Attached is a photo of the sticker on my sensor. The manufacturer refers to this sticker "the manual" -- yep, that's IT. It appears to show what I believe PCW suggested in his previous post -- that the pullup is built in? The rectangle with the diagonal slash through it is spanning between the signal wire and positive, with "300mA" defined. Does that make the additional resistors unnecessary?


Finally, the difference between the diagram in the OP and my setup: since I'm normally open, the input pin sees "high" until detection, then it sees Ground. Would my configuration just need to invert the signal in linuxcnc to indicate triggering, where this OP's config would show High as a trigger?

Thanks for the patience and shared experience. I've been dabbling at this build for months, and it's so close...yet so far...

I don't think you have a pullup resistor. The "manual" shows a load (whatever you are switching). The NO and NC just says what is the state without the sensor near some metal. So a NC switch will have +24v on the output away from metal and the NC will have +24v on the output while close to metal. Hope I got that the right way round. BEst bet is to hook it up to a power supply and play with a multimeter.

I think you will find that you will get spurious activity on the output without the pull up resistor on an NPN sensor...

This video explains it very well

Sorry for the double post!!! I didn't know where to post my question.

623/5000
My solution is now that I connect the OMRON sensors to 5VDC.

Another question: Beckhoff AX2500 needs differential voltage signals (+ 10V / -10V) for the frequency and direction of rotation. (A servomotor as main spindle drive). Can one now simply connect Spindle + and Spindle - with the drive connections and the should then function? So spindle+ and spindle- means differential output?

And lastly: Why not switch a relay between the inductive proximity switches and the 7I76E connections? 24V switched by the FieldPower connection via a relay? There would be the whole thing with the resistance simply fall away?

Gommiswald wrote: And lastly: Why not switch a relay between the inductive proximity switches and the 7I76E connections? 24V switched by the FieldPower connection via a relay? There would be the whole thing with the resistance simply fall away?

I do that for plasma cutters to limit imterferences, namely every limit switch and float switch has a relay power by 24V, the contacts just short the inputsbto the ground. Normaly closed limit switches, so whatever breaks betveen them, i get an error.
More expencive, more work. Much safer and fully isolated from the machine.

Hi
Now my little selfmade CNC Lathe works fine with the 7i76e Mesa Card. A great card with great functions. The problem with the feedback I solved from one side with the encoder output of the Beckhoff AX servo drive and the Index Signal I take from the Omron photosensor. I didn't need to change the voltage from 24 to 5V. I just connected the signal to an optocoupler relay and then to the encoder part of the 7i76e. First I had some problem, because I didn't get an index signal. This index signal is single ended and the signal A and B are differential. But at the moment, when I took away the connections of A- and B- and installed the jumpers 10-13 in the right order, the index signal runs great, so G76 threading works wonderful.

My experience is the one, that one has to try and change and try, until it works. But it is great, that there is a forum and I used it very often until the lathe worked as it has to work!

Best regards
Daniel

Hi Norbert
Thanks a lot for your wiring diagram. A really great helpful piece of work. Just one question. I want to add an analog in on input 0 for feed override for my Schaublin 128CNC retrofit. Have you maybe a link for a HAL example to configure this analog- in "feed override".
Regards from Switzerland
Daniel