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You would need a stiffer pullup so you get more than 12V at the 7I76E input

I would suggest 2.2K 1/2W

You could also use two separate inputs and an OR or MUX component
(the MUX component has the advantage of ignoring the other input
when not in use, but requires a signal to select which input shouls be active)

Hello again!
My next problem to get my machine running (it's running but not as precise as I want it) has to do with two switches.
My tool length sensor is a quite normal mechanical switch, that is NC and put +24V into input-08-not. That's working perfectly.
If I put my 3d Sensor (NPN-NO) into the line as the picture shows, nothing works. The 10k resistor (R1) before the Tool length switch puts the voltage down to 12.xVolts, the Input-08-not is set to "probing" permanently.
The 3D Sensor does nothing at all, not even the LEDs are active (the output is an open collector, I presume). What about diodes?
 

So, my next thought is to disconnect the two sensors from each other and use another Input of my MEsa 7i76e just for the 3D Sensor. This input should not be inverted for correct funktion. How can I do this with or without using an OR2 funktion?
My lines for the tool length are as follows

#---PROBE-IN ---
net probe-in     <=  hm2_7i76e.0.7i76.0.0.input-08-not    
net probe-in     =>  motion.probe-input

AFAIK, I cannot just net another input to motion.probe-input. But how could a OR2 look like?

Thanks for your help, again!
Hanno
 

If Step/Dir resistor networks or driver chips are being damaged
it means a voltage considerably outside the 0 to 5V range is being
applied to the Step/Dir pins.

First thing I would check is drive grounding and Step/Dir wiring
Routing step/dir lines parallel to servo motor wiring might also
cause enough EMI to damage the drivers.

An intermittent short to 24V wiring is another possibility.

A while ago, my MESA 7i76E broke; one channel just stopped working. I wrote about that here . I then found someone who repaired the card, after which the machine ran fine for half a year. He said he "replaced the resistor network" of the channel.

Today, the exact same issue appeared again. Joint 2 stopped working and after a restart it worked for a minute and went away again. This is exactly the behavior I saw last time.

This time though I was better prepared and had a spare 7i76E ready to replace the other one. After replacing it the machine ran fine - but after an hour the new card displays the same behavior, too! Clearly something is going on that breaks this channel... sometimes.

What would you do to diagnose this? Replace the JMC servo (with the built in controller) and hope for the best?

Hi Todd,

Thanks for your response — I’ll definitely give that a try, as it feels like my last resort with this current setup.

I've already disabled everything I possibly could in the BIOS. The only things I haven't touched yet are the memory timings and voltages. If this doesn’t work either, I’m honestly not sure what else is left to tweak.

I'm also considering switching to a Mesa card, possibly the 7i76EU, but I have zero experience with Mesa hardware. I’ll need to figure out whether it will work with my three DM542A stepper drivers, and also with my VFD, which is currently controlled over USB using: `loadusr -Wn vfd hy_vfd -n vfd -d /dev/ttyUSB0 -p none -r 9600`

Things i disabled next to the obvious, like settings for fixed clock speeds (fclock 1066, bclock 1000) disabling power management and disabling hardware that is not being used (BT, Wireless, serial, audio, fancontrol (disabled fixed on 100%)):

BIOS Settings (set to Disabled):

SMT / Hyperthreading
→ Disables logical cores to reduce cache sharing and latency spikes

C1E, C6, and other C-States
→ Prevents the CPU from entering sleep states, ensuring consistent timing

Streaming Stores Control
→ Avoids aggressive memory write optimizations that can disrupt real-time behavior

DRAM Scrub Time
→ Turns off background memory error checking to avoid unexpected memory bus usage

GMI Encryption Control
→ Disables inter-chiplet encryption on Infinity Fabric to reduce overhead and latency

XGMI TXEQ Mode
→ Prevents signal equalization tuning that could introduce instability or variability

DRAM Map Intervention
→ Disables memory remapping logic that can introduce unpredictable latency

DF Sync Flood Propagation
→ Prevents error broadcasts across chiplets, reducing the chance of system-wide stalls

Good day,
Adding a voice here as I think I saw another user having this issue: RPI5 with a 7i96, and after some time I get a solid red INIT light on the mesa card, and obviously at that point have to reset the card to continue. I cant make heads or tails of this just yet, but it might be related to idle. It may be specific to the 7i96 given the other poster also commented on that. I have 7i76EU on its way so will be able to test this and post back whether I experience anything similar. Currently the Mesa is on a 5v3A wall plug, and the RPI5 uses a somewhat official USBC RPI wall plug.

Working like a charm.
Thank you very much Peter!

P.S.
Damn self-made DB25 cables. Firmware initially didn't make any difference. Apparently cables on P1 and P2 were backward. Reversed both DB25 connectors and now I see both 7I76 and 7I89 and encoders are working. These Mesa cards seem to be very robust, even all wrong signals on all the wrong pins didn't make them go dead.

7I76EU firmware with 7I76 on P1 and 7I89 on P2

 

Each connector is independent, though module channels may differ between firmwares
Note on the 7I89, you may need to turn on Encoder power (depending on jumpering) and it
also requires  both cable  _and_ external 5V supply to P1.

PCW wrote:

Wrong firmware, 7i76eu_7i76x1_7i88_7i89d.bin is for a 7I76EU +7I88 (P1) + 7I89 (P2)

I'll take a look at making a config for a 7I76 (P1) and 7I89 (P2), but probably tommorow...
 

Would it be 7I76U (with sink/source I/O option and spindle/encoder interface) on P1 and 7I89 on P2?
Also, 7i76eu_7i76x1_7i88_7i89d.bin has 7I89 on P2. Should 7I89 on P2 work even if 7I76 on P1 doesn't? Or P1 and P2 handling is interdependent?

Wrong firmware, 7i76eu_7i76x1_7i88_7i89d.bin is for a 7I76EU +7I88 (P1) + 7I89 (P2)

I'll take a look at making a config for a 7I76 (P1) and 7I89 (P2), but probably tommorow...
 

That may be, but I have 7I76U and its manual says (www.mesanet.com/pdf/parallel/7i76uman.pdf page 5) that sserial should be on DB25 pins 7-10 (two of them in fact), while 7i76eu_7i76x1_7i88_7i89d.pin file has just one sserial on pins 11-13 and no spindle encoder. It instead has 2 additional stepgens which my 7I76U doesn't have.

Might want to wait for confirmation from PCW, but to me it seems all good, and yes sserial's must be there as 7i76 has a sserial port and uses another sserial channel for IO.

Here it is. 
As I see it, pinout for P1 connector (where 7I76U is connected) is wrong for pins 7-13 (Sserial and spindle encoder)
 

koch777 wrote:

That one has all the right pinouts, but seem to be for older generation of 7I76 (Spartan FPGA?), not sure it will work for my 7I76EU (Efinix FPGA)

It does not work and might brick the card, well i am sure it will brick it, but being Mesa there might be ways to save it, so do not flash that.
Post the result of mesaflash readhmid here se we can have a look.

Hello everyone,

So, I have this configuration:

• Main board is Mesa 7I76EU
• 7I76U connected to main board expansion header P1
• 7I89 connected to main board expansion header P2

Main board's +5V is connected to P5; +24V field power - to TB1.
Actually, never mind, main 7I76EU is not a problem, it works, everything's detected, steppers are moving, spindle/spindle encoder are working, MPG is working.

Now, expansion 7I76U (on P1 header) is indicating communication failure (red led in the middle of te board). It doesn't show up in halconfig (should it?). Field power is there, cable power from main board is there.

For 7I89 I see all 8 encoders, but encoder inputs do not react to signals from encoders. None of the encoder input-a/input-b/rawcounts change despite the fact that physical signals from encoders are. Encoders are TTL and so 7I89 is jumpered accordingly.
+5V power to 7I89 is connected to its P1 and cable power from 7I76EU is activated as well (per 7I89 manual). Encoders are powered and working just fine (checked with oscilloscope).

Firmware I load is from mesa website: 7i76eu_7i76x1_7i88_7i89d.bin
It is somewhat strange as its 7i76eu_7i76x1_7i88_7i89d.pin file has stepgens 10/11 where 7I76U (P1) should have Sserial and it also has Sserial where should be MuxedQCount (spindle encoder). Basically I/O for DB25 pins 7-13 is all wrong for 7I76U.
Probably that's why my 7I76 doesn't work.

I'm afraid to load firmware from post www.forum.linuxcnc.org/27-driver-boards/...7i89-firmware#240149
That one has all the right pinouts, but seem to be for older generation of 7I76 (Spartan FPGA?), not sure it will work for my 7I76EU (Efinix FPGA)
It also has clock high frequency set at 200MHz, while 7i76eu_7i76x1_7i88_7i89d.pin shows 160MHz.

How can I get out of this predicaments?
Can anybody help?