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Hello,
I made a custom version of the MESA Electronics 7c81 FPGA Card that I thought some of you might find interesting. 
I've attached images of the progress I've made so far. 





I haven't ordered the PCB yet, as I wanted to ask first, if any of you guys on here can find anything wrong with it. As I'm a student with limit budget I'd like to be a little more reassured that I'm not missing anything.
I used the  7c81 Schematics  found in this forum post and the schematics of the official  RPi CM5 IO-Board  to create my own schematics.





I have a few questions I haven't found a good answer for and I'd be happy to recieve constructive criticism on any part of the design.

• The SPI0 Bus of the RPi (SDA0, SCL0) is shared by the Serial Flash for the FPGA and one of the MIPI DSI/CSI-2 FPC connectors. Will this cause conflicts?
• I wasn't able to avoid routing traces under the FPGA, will this be likely to cause problems or will I be able to get away with it?
• Is it a good idea to ground pour the top and bottom signal layers of the 4 layer stackup, if I'm already using the two inner layers as ground planes?

Thank you in advance!
Niklas
 

Hi All,

I have an old VMC that is based on the Mitsubishi Meldas controller and Mitsubishi motors. The machine is in good mechanical condition but the control has given up the ghost, so I plan to replace all the servo drives and do a new controller based on LinuxCNC. 

A few questions that I'd like some input on:

• The machine has 3 phase 1kW, 3000 RPM motors on it for the X and Y axes and 2kW, 2000 RPM for the Z axis - they are Mitsubishi HA83  and Mitsubishi HA103 and have rotary encoders on them that means the original servo drives keep track of the absolute position. Does anyone have any thoughts on sticking with this motors or replacing them?  If replacing them, any suggestions for a good brand/family?
• If I just replace the drives, then it seems that the Nidec/Control Techniques Unidrive M700 series might be a good choice? Any thoughts. Ideally I would power the drives directly from the 3 phase 415V supply (the machine currently has a transformer which delivers 200V to the drives).
• On the control side, any suggestions as to which Mesa cards are well suited? Previously I have converted machines using the 7C81 and a Raspberry Pi and 5i25 and PC - I think this will need quite a lot of I/O so I'm thinking a PC based card this time.

Thanks,
Greg
 

Hello i have a Feeler Ftc-280 which im currently retrofitting from its fanuc OT controller to a ethercat system. Some specifications so you know what im working with: 11kw fanuc main spindle (i will run it on a regular vfd with modbus ), 1.2kw x axis servo, 1.8kw z axis servo, 2.2kw hydraulic pump (for driving the turret, tailstock, probe arm, parts catcher and chuck). It´s a quite rigid machine weighing 5 tons with some 50mm thk ballscrews. I have purschased most electronis and have gotten the lichuan servo motors and beckhoff devices up and running. I already bought a raspberry pi so i will not be able use probe basic. Is there another nice gui for lathes?

For sale as a group. $500 US shipping included.

MESA 7C81 is FPGA motherboard host for a Raspberry Pi
1.5" RPI GPIO cable for 7C80 and 7C81
DIN Tray 107MM X 102MMFor 7C81

Raspberry Pi 4 Model B (8 GB).
Includes SanDisk Ultra 32GB microSD card with RT PREEMPT 6.6 linux kernel version of Raspberry PI OS. See this thread regarding installation.
Pi heatsinks, power cord, fans.

KBSI-240D (9431) Signal Isolator. DIN tray for this card.

2 DPDT Signal Relay Module Board, DC 24V . DIN tray for this card and PWM card.

Ideal Power's 56YSD15S 24v DC 15W DIN Rail Mount power supply

3.3V PWM to 0 to 10 V Voltage Converter . DIN tray for this card and Relay card.

Three signal isolation cards I designed and fabricated. DIN tray for this card. Ribbon cables from 7C81 to signal isolation board. Connectors and pins for the connectors that mate to the signal isolation board.

Cards are described in detail in the next post.

 
 
 
 
 
 
 
 


 

Yes, RPi suggests that parallel processing 1.5x that number of cores works well. I had also always used the number of cores.

Hey Guys,

If you have a moment. This video as well as the code is super rough, but I wanted to raise a bit of attention for those that are interested:
I have a modified Ender3 3d printer with two rotational axes. It is controlled by a raspberry pi and an cotopus board 1.1 with remora linuxcnc.

github.com/bbo-git/5AxisSlicerBlenderAddon # indexed slicer with cura engine backend
github.com/bbo-git/5AxisKinSlicerBlenderAddon # spiral toolpath creator and Gcode generation



with kind regards,
Jairo

Hi all. I am trying to figure out the last step of configuring my machine. For background, I am using a Raspberry Pi 4b with the current LinuxCNC image from the downloads section. The RPi is connected to a Byte2Bot parallel hat which is in turn connected to a parallel port breakout board. I have managed to figure out all of the step, direction, and limit switch stuff and now have a machine that moves, homes, etc.

The final thing I want to do is define an input to LinuxCNC to stop motion if one of my closed loop stepper motors throws a fault. Essentially like hitting the E-stop. The stepper drivers each have a fault output pin and all of these fault outputs from the drives are wired to parallel port pin 10 of the BOB. This should be GPIO 25 (GPIO connector pin 22). For everything else I have done I have used templates and just been able to change pin numbers. I believe the hal entries would look something like this:

net driver-fault <= hal_gpio.GPIO25-in
net driver-fault => iocontrol.0.emc-enable-in

I believe this would result in a stepper driver fault essentially tripping the emergency stop.  I don't have a way to test this right at the moment and was wondering if someone could take a look and see if my thinking is correct?

Thanks,

John B 

If you are using the byte to bot supplied files they won't work .
The images you supplied aren't really readable.
What I would suggest is read the docs for the hal_gpio driver and modify your files to suit.
Then loudly complain to byte2bot their files are useless for the raspberry pi .
Also when asking for help attaching your hal & ini files is most helpful.
Also attaching the error files rather than photos of the screen helps as well.

No, it has nothing to do with the kernel module, disabling the kernel module won't stop the service running. The messages are coming from the service systemd is attempting to start.
One option is to mask the service and have no swap available.
The second option is as I've described and have a little swap if needed.
But it's not the kernel modules that are issue.
Not to be unkind but I didn't pull the solution out of my backside, I spent some time researching the issue, as to what was causing the issue, how to fix the issue and what was supposed to be happening.
The service is for setting up swap in compressed ram. Whilst there is a little overhead in compressing and decompressing the speed for accessing ram is far far quicker than accessing a drive of any sort. If no swapping occurs it will have no affect on latency.
And even before I offered up my solution I ran a few tests to make sure I had the method correct and there were no issues with latency or anything else.
And yes I should have been more vigilant when initially putting everything together.

PLEASE NOTE
all references to zram.service should be zramswap.service

That would work if network manager was the method used to manage the interfaces and network-manager-gnome was installed. But that's not the way the images are built.
And honestly if you don't setup a firewall as well.....

Question should be
How to set a hotspot on Linux?
Any Linux distro that uses network manager = easy, it goe something like:
-right click on the network icon located up or down on the right side close to the clock
-choose "edit connections"
-double click on the wifi connection
-go to "Wi-Fi" tab
-select "hotspot" from the drop down menu and add info as neede like BSSID etc
-click save
-close
left click on network manager and select the wifi network to reconnect
done.

zram is a kernel option which can be disabled by adding zram.enabled=0 to boot.txt
Do you guys want to try that?
The Debian tools are not really necessary. The kernel docs explain how to configure it manually.
www.kernel.org/doc/html/latest/admin-guide/blockdev/zram.html

No and if you want to you're on your own. Totally beyond the scope of this forum.
And not a good idea for too many reasons.

Hello did anyone tried to set up a hotspot on raspberry pi to connect remotely? 

Actually it's my issue for not checking the boot logs, the scripts setup the zram.service. Whether Raspberry OS uses zram is not related to our images, as we use Debian.....as of course you know.
The zram.service is part of the image builder, I've modified the process so the service shouldn't be enabled and later on install systemd-zram-generator and create a config that will use 1GB on a 4GB system, this can be modified if required.
As you can see zram tools are installed, this is whether or not systemd-zram-tools are installed.
The issue is because Bookworm uses systemd the package systemd-zram-generator is required, this is the missing piece of the puzzle. During the build the a different script is used to zram0 which fails.

As you can see from below zram0 is used for swap.
Without the mods I've describe above there is no swap. Whether it's need or not, but on a typical debian x86_64 install usually a 1GB swap partition is created.

As you can see it really doesn't affect the total free memory when it's not in use.And BTW it not caching memory nor mamory glands, but is creating a swap partition that is compressed in memory.

The simplest option is just to mark zram.service as masked and have no swap.

So at the moment I'm building an image with the mods.....and make sure I've done it right.

Rob