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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!

 

Spyderbreath wrote:

Warning: Spoiler!

At the risk of the blind leading the blind, to me that is not quite the right question. That chart is for your micro-stepping. Like the 800 is 4 microsteps, if you're using a 1.8 deg. stepper. I have always looked at it this way - What are you doing with the motor? If your opening a door or driving a ram, picking 800 would be fine, but using that on a belt or lead screw may very well end up leaving artifacts in the work due to the rougher movement between points. The downside is the more micro-steps you have the more torque you lose. 3200 (16 micro-steps) seams to be a reasonable middle ground that most use as standard. The controller will put out as many steps as directed by LinuxCNC to make a revolution, just a matter of how fast it can do it. Whatever you chose, that gets figured out when you tell LinuxCNC in your .ini file how many pulses it takes to move one unit. That is set with the SCALE on each axis. Like for me, I have 16 micro-steps (3200) and a 5mm pitch screw, which works out to SCALE = 640 or -640 depending which way you need the motor to move.

 

Thanks for reply,
I have set 12800 and testing some gcode only with Y working.
I don't want to cause problems when all the stepper and spindle are physically working.

1. Normally csp I would say. For a spindle motor csv.
2. I prefer to send position in machine units to cia402 and do the scaling closer to the drive. But that's just me.
3. lcec comes from here github.com/linuxcnc-ethercat/linuxcnc-ethercat and there is a link in there to a reference guide. Unfortunately it doesn't cover sdo uploads. But it's done like this. Example comes from one of my ect60 stepper motor drivers.The sdoDataRaw has some quirks. First you must enter 4 bytes for a 32-bit variable, 2 bytes for 16 bit and 1 for 8 bit.
Note the byte order, 4000 which is hex 0x0fa0 is entered as "a0 0f". 100 (hex 0x64) is entered as "64 00",

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?

Yes, to swap a tool for another tool that is the case, but my spindle was empty.

The carousel needs to move away to give clearance to the Z assembly during probing. Otherwise the probe can't reach X0 without the Z assembly running into the carousel.

If I would place the probe on the left side of the spindle, possibly the carousel wouldn't need to move away, only when it needs to swap for the toolsetter.

But the consequence would be not having full probing range on the end of X axis (without extending the gantry), which maybe isn't really an issue.
But I would need to find a way to block the spindle from going into the carousel work area during 'non-toolchange' events.

For now I'll just accept the situation and carry on with the small delay, until I got the whole toolchange process sorted.

Im at the point now where the carousel extends, gets detected, spindle moves to clearance height, spindle unclamps the tool etc..
All 5 sensors are working, Carousel Home, Carousel Index, Carousel IN position, Carousel OUT position and the Spindle Tool Clamped and Tool Released sensors.

Now its time to program the final movements, placing and removing a tool from a pocket.
Will be a little different probably compared to other carousel toolchangers where the carousel moving in and out takes the tool from the spindle.

When no tool is loaded it has to move down, clamp the tool, moving to the right to take a tool from the pocket, carousel retract, spindle up again and resume.
Or with a loaded tool it has to move in front of the carousel, moving to the left into the pocket, unclamp, up, rotate to new tool, down again etc.

Should be fun, hopefully it won't get fooked. :-D

Anyways, the basic functionality is working.
I still have to wire up and map the ATC spindle PNP sensors to detect clamping / unclamping and the sensors for the out position of the Carousel cylinder, before I can try to run a toolchange. But that should work out fine.
Once everything is working, I'll do a writeup how it's configured.