CNC router AKA "Chippy CNC Workbench" - Yaskawa based PLC

I have been working on this CNC router for the past 4 years or so and finally have it working reasonably well.
It acts as my woodworking workbench as well as a CNC router.

The wood plaque in the picture was the first real part made. The text is pocketed with a 1/16" router bit. The program for the text was 10,026 lines of code, and completed in 12.9 minutes or ~ 13 Gcode lines / sec on average.
I did the program in Fusion 360 and posted with HAAS Gcode output which then ran on the machine with a little added code to adjust for not having an ATC.

The Hardware is:
3 axis Gantry (X axis ~70" travel, Y axis ~ 49", Z axis ~ 12", but can go lower off the end of the table.) - hoping to be 4 axis some day
25mm Ball screws + Linear guides

Steel tube frame (Blanchard ground flat table frame)
Frame is 3"X 6" 1/8" wall steel tubing for the gantry. Table frame is 3"X3" tubing with extra 1/4" thickness for the linear rails.
Bed is a glued up douglas fir table with Maple edging. (3" X 37" X 104") - sacrificial MDF sheet on top.
Machine stiffness appears to be ~ 5lb / 0.0001 inches of deflection at the router tool in all three directions.
Machined aluminum for the Z axis and ball nut connections.

Yaskawa MP3300 PLC with 400W Sigma 7 servos
5:1 gear reducers on each axis (3arc min of backlash - China)

Spindle: currently just a porter cable router
Just purchased : 4.2KW 24K water cooled ATC spindle +E550VFD from china - BT30
Working on figuring out how to interface from the Yaskawa IO card to the spindle.

PLC Software:
Wrote PLC software from scratch in Motionworks IEC - Structured Text.
Separate POUs for Axis state machines, Network connectivity, and program execution.
Accepts Gcode over Ethernet (unlimited length programs)
Streams the machine execution log back to the PC
State machine operation for both Manual (Jog) and Auto (Program) modes
Implemented Gcode interpreter for HAAS Gcode
Several moves are buffered allowing for blended motion
Implemented Incremental and absolute movements for linear and circular motion using PLCopen group movements
Have not yet implemented:Helical milling, Drill cycle. On the to do list
Unit tests and functional tests implemented to exercise functionality in a parallel project

PC software: Wrote PLC software in python
Displays current position, velocity and machine status
Load and run Gcode programs
Implements Manual jog, home, and power for each axis.
Tool length offsets + Fixture offsets
Preprocesses Gcode files and adjust feed rate to ensure maximum acceleration for each axis is not exceeded, and minimum Gcode command time is not exceeded (~20 ms). This ensures smooth motion during the program for collinear movements. This effectively provides an infinite look ahead buffer.

Interface is a laptop running the PC software on the same wifi network as the CNC router.

I drew up the system diagram for the ATC spindle along with the VFD and a micro controller to act as an interface. This is after a large number of questions from the spindle manufacturer.
I have a digital IO card with the MP3300 and I am thinking of using 8 bits to generate the speed control on the VFD.
Adding the ATC is a bit larger of a project than I was expecting. There are a couple of key requirements that are driving the use of the micro controller (Arduino mega).
- 10V analog output
- Thermistor monitoring (shut down at 60C)
- The location of the VFD is supposed to be within 2m of the spindle.. which will not be near the PLC. So by placing the Micro controller near the VFD and Pneumatics I can keep that functionality separate from the PLC box.
I am now debating whether I should spin a shield board for the interface circuitry on the micro controller. Or perhaps just had solder a protoboard / shield. OSH seems to do boards pretty cheap and reliably, and they always look nicer than a mess of wires.
I am also waiting for info on the breaker required for the VFD. It is a 5.5KW on 4.2KW spindle.. I am thinking it might be 50A 240V.

I was also thinking about trying to control the VFD over RS485 (Modbus). I would need to get a Modbus TCP gateway, and programming the VFD over Modbus seems a bit iffy given that I have never tried using Modbus over TCP -> Gateway -> RS485 .
I could also create a RS485 interface for the Micro-controller to control the tool change and other IO. Doing all that work for 485 control just doesn't seem worth it.

The spindle arrived, and was well packaged.
Here is what was in the box:
Jianken 4.2KW 220V 24,00rpm 1000Hz BT30 AT spindle with ceramic bearings.
5.5KW VFD
water pump
BT 30 tool holder
A clamp used to hold the spindle

Here is what it looks like.
https://www.youtube.com/watch?v=p3b6k8myuq0

I completed the ATC spindle design and integrated it. The interface between the Yaskawa PLC and the Jianken Spindle uses the Yaskawa LIO card and some voltage translation. Here is a video going over the details of the design as well as the configuration for the VFD.
https://www.youtube.com/watch?v=D1YdmcnDXec&t=415s