RPi 4B w/LinuxCNC 2.9.3, Mesa 7C81, Isolation Card, PWM Card, Relay Card, More

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.

 
 
 
 
 
 
 
 


 

I was planning to use this controller setup for a Precision Matthews 728v-t mill using Teknic ClearPath SD servos. I was not keen on interfacing to the servos and mill spindle directly from the FPGA card, so I designed a 3v - 5v level shifting buffer / isolation card. I did the design in KiCad and all KiCad schematic and PCB files are included on the microSD card. Here is the schematic of the card.

 

Here is how the card was going to be used in this controller setup. The 7C81 had been flashed as a 5ABOBX3D.  There are three cards because the minimum board order was three. I decided to build out all three in case there was an issue with one, and to have spares. The boards have been powered up and tested. They are fully functional.

Obviously given HAL you don't have to use the board exactly as I intended.

 

Here is the how the controller power was planned.

 

As noted the MicroSD card has the OS and LinuxCNC. It has the KiCad files. It also has the data sheets and documents for boards and components used on the boards I made.
 

Here is a screenshot of the system running. The Pi is mounted on the 7C81.
 

Here are screen shots of the directories with the included files mentioned above.
 
 

If you have any questions you can email me directly at gene_weber@yahoo.com

Best

Depending on the way you jumper the 7c81, 3v - 5v translation isn't required as the 7c81 provides level shifting, hence the reason $5 chinese BoBs can plug directly into the 7c81, the 7i92 series are the same as well.

I am aware that the default jumper is for 5v tolerant. My preference was for setting it to native 3.3v and adding level shifting drivers between the 7C81 and the other components.

Out of interest, apart from the speed increase on the 7c81 side that would be mitigated by the off board level shifting, what was the the thoughts in that decision. I just went with on board level shifting on my "roll my own" 7c81 board, tho it can run other configs and not just hostmot2 firmware.