Troubles to get started with SD240 Retrofit

Ahh, looks like the index is single ended, maybe that's the issue.

Unfortunately the 7I33, each encoder input is all differential or all single ended

So one thing to try would be to select single ended instead of differential
encoder mode one the 7I33. This is not ideal as it less resistant to noise
but may be OK.

If setting the 7I33 to single ended encode mode works, there is also
the possibility of using custom firmware that puts all the index inputs
on one 7I33 encoder connector  so you could have differential for A,B
but TTL mode for the Index signals.

Another possibility is to add a TTL to differential converter for the index signals
Mesa has such a thing, but its really just 1 chip on a board

(26ls31 or one of the many equivalents)

Ok- so the first thing you suggest to try would be single ended.  Is just setting the jumper DOWN really all I need to do in this case and the axis should (ideally) behave like before? Or will there be more to it?
Well, I will simply try to jumper it to TTL and see if I can run the axis single ended properly or not.

Years ago I remember such "differential converters" on Uhu´s (DC-drives) - these where small and pretty inexpensive parts. But I just knew them for converting A+B channels to A/A* and B/B* , did not need the index in this times....
If I could use such converters to get a differential Index signal out of a single one and so solve the issue I would be fine with it.
Unfortunately I can not simply exchange the encoders as these Fanuc encoders seem to be part of the servo motor and the rear end bearing of the motor.

So I will first try to run the axis with the 7i33 jumpered to TTL, see how it behaves with the single A/B signals and if I can use the index signal then.

Thank you
Sigi

 

So I set the jumpers on the 7i33 for X- and Z-axis to TTL (DOWN) and entered the USE INDEX- YES in the INI. Both axes behave normal and I think they home with using the index now.
Sequence:
Homing movement
Home switch trips- "home sw. X" gets yellow, "enable index" lights up yellow and the axis moves forward a bit further.Then the "hm2_7i80.0.encoder.00.input-index" flashes yellow very short, the axis frees the home switch and moves on to home-pos, stops and "x-axis homed" lights up yellow and the DRO says 0/0.

Z homes the same way. 

I think thats exactly what I wanted to achieve- correct? 
The spindle I guess can be indexed also, otherwise threading would be impossible...but the spindle likely just needs the index, A/B will not be necessary on a lathe- or am I wrong?
Well lets see how the next step can be solved.

The important hint was that the 7i33 just can process ALL inputs as TTL or ALL inputs as differential!
Thank you all so much
Sigi

Yes, sounds like its working now, sorry I missed that the index was single ended.

The 7I33 can just change the input mode of each encoder interface (A,B,IDX), not pin-by-pin
as most newer Mesa cards can do.
 

PCW wrote:

The 7I33 can just ..., not pin-by-pin as most newer Mesa cards can do.

 

Is there a better alternative to the 7i33- just in case?

How can I get the spindle indexed?  Setup at the spindle is different- the motor encoder (G5) is just wired to the amplifier and not accessible for me, but a second encoder for threading (G2) is driven by the spindle via a toothed belt (1:1)
Signals for G2 are similar to the axes encoder signals, Ua1/Ua1*, Ua2/Ua2* and the index Ua0 single (non differential)

Mechanical Setup:

 

Wiring of G2:

 

I have the spindle running with G2 as a feedback- this works fine but I will need the index for threading.
How can I manage this?   I tried to make the index visible in HAL Scope, but can not set the "index enable" (get an error message)

The encoder G2 is connected to the 7i33 as ENC02, as said works fine for spindle feedback so far.

Sigi

I think I found most settings in  linuxcnc.org/docs/html/examples/spindle.html
Lets see how far I get.
Only thing is that my encoder is a 2000 pulse encoder and in the example its a 100pulse per rev. encoder. We wills see...