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in the near future. The stepper-ninja hal driver run in the servo-thread so the minimum width of one input is 1 servo thread refresh in length, with 1KHz servo-thread its 1mS, something like this: when you see a ruler, all 1mm division represents a servo thread cycle, the signal only starts in the divisions and only end on the divisions. With low spindle speed its probably working, but if you want better threading you use printer port for the lathe spindle encoder.

Hi All,I’d like your input on my planned setup.
As I mentioned in my previous post, the latency on my new machine was so high that I had to switch from the parallel port to a Mesa card. Earlier this week, I received a Mesa 7i76EU board. It looks awesome—if a bit overwhelming at first glance!My plan:

• Motors:
  I’m using 3x Longs DM542A stepper drivers, which I plan to connect to Stepper 0/1/2 outputs on the Mesa board, using what I believe is called a “single-ended” wiring configuration. My plan is to connect +5V to the ENA+, DIR+, and STEP+ on each driver, and wire the ENA (5V), DIR-, and STEP- of each driver directly to the corresponding outputs on the Mesa card.
• Spindle:
  I have a Huanyang VFD 1.5KW for spindle control. For now, I’ll keep my Modbus-over-USB setup, which seems to work well enough. I’ve read that getting Modbus running directly on the Mesa board requires a bit more advanced configuration, so I’ll save that for later.
• Homing Sensors (Capacitive, 3x):
  My plan is to connect the +24V supply to the positive (brown) wire, and field ground to the negative (blue) wire of each sensor. I intend to connect the sensor output (black) wires to Input 1, 2, and 3 on the Mesa card.

Questions:

1. Current-limiting resistor for home sensors:
   For the capacitive homing sensors, do I need to add a resistor between the output pin of the sensor and the Mesa input to protect against overcurrent? In the past, I’ve blown a few sensors and started using resistors to protect them, but those were cheap sensors—the Mesa card isn’t!
2. 2-wire touch probe:
   For my two-wire touch-off probe, I plan to connect one side to +24V field power and the signal wire to Input 4. Here too, should I add a resistor to avoid potential shorts or overcurrent situations?

Bonus questions:

• Any recommendations for best practices when wiring sensors and stepper drivers to the Mesa 7i76EU?
• Are there things I should definitely avoid to protect my Mesa card or improve reliability?
• For those who have set up Modbus on the Mesa board, how steep is the learning curve compared to using Modbus over USB?

Thanks for your advice and experiences!

Hi, I my name is Chrstian and I tend to read more on forums than to write. But as many others I am in some kind of a dead end and could use some advice...

Backstory:
I bought an used self build CNC Router. The controls were build around an USB Smooth Stepper and Mach3. Since the controls are not repair friendly (too much stuff packed in too little space with custom layout boards and same color wires) and I am more a Linux than a Windows guy, I am in the process to upgrade to LinuxCNC.

I use an 7i92 and an 7i76

One of the last steps missing is the spindle control (1,5kw china spindle with ER16). For some reason the person, who built the router went with an "Lenze 822MV" 400V 2,2kw VFD.

After the long introduction, my question:
Where can I get my 10V reference (Spindle +) from this VFD? If someone might take a look and give me a hint, I would appreciate it.

The manual for the "Application IO Module" that is used, can be found here: www.becker-antriebstechnik.org/WebRoot/H...__v6-0__DE_EN_FR.pdf
(page 21 starts the english description)

The manual for the actual VFD (should not matter that much, just in case):https://www.lenze.com/en-de/products/inverters/previous-products-inverters/8200-motec

Currently connections A1, 2x7 (GND), 59, 28 and 2U are connected. I have absolutely no Idea where they go to...

In case the VFD does not have an 10V reference voltage, what are my options? Do the cheap 20€ 4channel 2,5V, 5V, 7.5V, 10V reference voltage things from ebay work?
Am I missing something?

Thanks in advance for the help (and all the help I got from the forum without having to ask).

Christian aka TheRealMable

I wouldn’t mind rewiring everything — my setup is quite simple, and the CNC machine is fairly small. For me, building and tweaking the CNC is part of the fun of the hobby.

I’ve read that many of you use various Mesa cards. I was hoping the 7i76EU alone would be a good starting point to learn how to work with Mesa hardware. Do you know if that’s the case? I saw some brutal shipment costs (like 200 dollar plus, so i will have to search for an European supplier, i'm in the Netherlands)

If the 7i76EU would allow me to completely move away from the parallel port, that would be a big plus — especially since I’m currently limited by base-thread latency.

[EDIT]

I see a seller with reasonable shipping costs, not sure if its a trusted compane EUSurplus?I think i am planning to switch to a Mesa board and wanted to check if the 7i76EU is the right fit for my setup. This is what I’m working with:

• 3x DM542A stepper drivers (they use step/dir signals)
• 3x LJ12A3-4-Z/BY inductive proximity sensors (used for homing)
• 1x Huanyang VFD (spindle, controllable via 0–10V or RS-485 Modbus (I think because i now use it over USB)

From what I’ve researched, the Mesa 7i76EU seems like the best option. Here’s why:

• It supports up to 5 stepper/servo axes via step/dir signals (perfect for my DM542A drivers)
• It has 32 opto-isolated inputs which should work well with the 24V NPN homing sensors
• It has 16 outputs, which are configurable (sourcing/sinking)
• It includes an analog spindle output (0–10V) for VFD speed control
• It supports RS-485 communication if I decide to use Modbus for the Huanyang VFD
• It isolates field I/O power from logic power, which helps protect the system

Important to note:

• The sensors might need a pull-down resistor to give clean logic signals when connected to 24V. I already solderd a pc to convert the 30V signal back to a 5V system with opto's
• I will need to supply 24V field power to the board 
• I understand the 7i76EU requires a second Ethernet interface on my PC (either a second NIC or a USB↔Ethernet adapter)
• I still need a PREEMPT-RT kernel, but I won't have to worry about tight base-thread latency anymore

Does this sound correct to those of you with experience using this board?Thanks in advance!