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I wrote this up in chat gpt pretty quickly I think it just about covers all of the bases here of the project.

CNC Plasma Table – Electrical & Wiring Requirements

Project: Remote design of electrical system + wiring documentation for LinuxCNC plasma table
Client: TCB Metal Works

1. Project Overview

You will remotely design the complete electrical and control system for a custom CNC plasma cutting table powered by LinuxCNC.

You will create:

Complete wiring diagram set (schematic + physical routing)

Full Bill of Materials (BOM) with real part numbers

Wire gauge, shielding, grounding, and EMI mitigation plan

Bulkhead connector list + panel layout

Mesa board selection + full LinuxCNC I/O map

Integration notes for all components

Testing & commissioning checklist

This is a 100% remote engineering job — no physical inspection of hardware is required.

2. Available Power Sources

Near the machine:

220 VAC available

460 VAC available

No dedicated 110/120 VAC, which must be generated using a control transformer if needed

Engineer must design the incoming power strategy and transformer selection.

3. Motion Hardware
3.1 X & Y Axis – AC Servos (Provided)

3× A6 Series 1000W RS485 AC Servo Motor Kits

3000 rpm

3.18 Nm

17-bit absolute encoder

IP67 motors

Axis layout:

Y axis: 2 servos (dual-drive gantry)

X axis: 1 servo

Notes:

Motor-to-drive cables are already supplied by the manufacturer.

You do not need to design or evaluate those cables.

Engineer must:

Design AC mains wiring to each servo drive

Design control, enable, alarm, and ESTOP signal wiring between drives and Mesa

Include needed fuses, breakers, filters, and terminals

Provide cabinet layout and routing plan

Include proper grounding and shielding recommendations

3.2 Z Axis – Stepper Motor (Needs Driver + Cable)

PV267-D2.8AA stepper motor — Oriental Motor

Stepper driver not provided

Stepper motor cable not provided

Engineer must:

Select a compatible stepper driver suitable for PV267-D2.8AA + LinuxCNC step/dir

Define driver voltage supply requirements

Design:

Step/Dir wiring from Mesa

Motor wiring from driver to Z motor

Required cable shielding, gauge, and insulation

Connector type and strain relief

4. Control Electronics (Mesa + Power)

Engineer must select Mesa hardware capable of supporting:

3× servo axes

1× stepper axis

THC-AD

Ohmic sensing

All limit/floating switches

Plasma start / Arc OK

E-stop & safety I/O

Deliverables:

Recommended Mesa board combination (e.g., 7i76E, 7i96S, 7i85, THCAD, etc.)

Justification for chosen hardware

Complete LinuxCNC I/O mapping

Required DC power supplies (24V / 5V / others)

Proper AC distribution, fuses, breakers, and protection devices

5. Torch Height & Ohmic Sensing
5.1 THC-AD Integration

Engineer must design:

Raw arc voltage wiring from Hypertherm HT2000 to THC-AD

THC-AD signal wiring to Mesa

Required shielding and filtering

Scaling notes for LinuxCNC

5.2 Ohmic Sensing (Planned)

Engineer must:

Recommend a compatible ohmic board

Provide wiring diagram for torch → ohmic board → Mesa

Specify cable type and shielding

Document signal polarity & behavior

6. Hypertherm HT2000 Integration

Engineer must design wiring for:

Required signals

Torch start / trigger

Arc OK

Raw arc voltage (+/–) into THC-AD

Required protection

Isolation (if needed)

Surge suppression

Filtering

EMI protection

Routing rules

Arc voltage wiring must be kept separate from low-voltage control wiring

7. Limit Switches & Floating Head
X Axis

2 limit switches:

X-min

X-max

Y Axis (Dual Gantry Drive)

2 limit switches:

Y-min

Y-max

Engineer must propose a reliable gantry squaring / homing method for the two Y motors.

Z Axis

2 end-of-travel limit switches:

Z-min

Z-max

1 floating-head switch (touch-off)

Engineer must:

Select appropriate switch type (mechanical or prox)

Provide wiring diagrams to Mesa

Specify wire gauge, shielding, and cable routing

Provide LinuxCNC input mapping

Include any debouncing/filtering requirements

8. Wiring, Shielding, & EMI

Engineer must specify:

Wire gauges for:

AC mains

Servo drive feeds

Stepper driver feeds

Stepper motor wiring

Limit/floating/ohmic wires

Plasma signals

DC supply lines

Shielding requirements for:

Step/dir

Limits/floating/ohmic

Arc voltage

THC-AD lines

EMI considerations

Cable separation

Ferrite locations

Filtering recommendations

9. Grounding & Bonding

The engineer must design the grounding/bonding approach.

Important physical detail:

The water table, gantry, and control cabinet are three separate physical assemblies.

The engineer must account for this when designing:

Grounding/bonding layout

EMC/EMI mitigation

Plasma return path considerations

Ohmic sensing grounding

No grounding method (star, bus, single-point, etc.) is mandated — the engineer chooses the correct approach.

10. Control Cabinet & Bulkheads

Engineer must design:

Cabinet Layout

AC distribution, transformers, PSUs

Mesa boards

Servo drives

Stepper driver

Fuses, breakers, contactors

DIN rail layout

Ventilation/fans

Bulkhead Connectors

Used wherever practical for:

Servo cables (using glands or pass-throughs)

Z stepper cable

Limit/floating switches

Ohmic sensing

Plasma start / Arc OK

E-stop / operator controls

Ethernet access

Engineer must specify:

Connector type

Pinout

Panel cutout style

Labeling

11. Documentation Package

Engineer must deliver:

11.1 Wiring Diagram Set

Full schematic

Cabinet wiring

Field wiring

Power distribution

Grounding/bonding

Bulkhead connector pinouts

11.2 BOM

Complete list of:

Mesa hardware

Stepper driver

Transformers / PSUs

Switches

Connectors

Wire/cable

Protection devices

Cabinet hardware

11.3 I/O Map

All LinuxCNC inputs/outputs

Axis definitions

THC/ohmic mappings

E-stop & safety signals

11.4 Commissioning Checklist

Power-up verification

Servo enable/jog

Stepper test

Homing / gantry squaring

Z floating-head test

Plasma start / Arc OK

THC test

Ohmic test

EMI/noise checks

What material is being milled?
You wont like this, but that can very easily be mechanical flex from aluminium parts, there is reason why cast metal is used for mills.
Still, a quick test for that is to make the same part much slower and check if the error is smaller.

About the following error, there is no real position feedback, only position feedback from stepgen.
That P=500 is ok for your 2 ms servo-period?
 

Mwchanical issue maybe or backlash of your acis settings are correct.

Your approved, the move to private was not my doing, FB forced group chats to private chats last month i think.

Thanks for the info. I sent a request to join the probe basic facebook group. It appears to have gone private in a new group that is members only.

Give this a try
forum.linuxcnc.org/9-installing-linuxcnc...an-edition-6?start=0
or if you are OK with 2.10 version dating nearly a year back, try this
forum.linuxcnc.org/9-installing-linuxcnc...-1-linuxcnc-2-10-iso

thank you I decided to take a few days brake on this reinstall.. "note to myself dont touch things that work lol"

Tried first reinstall 2.9.4, that did not help. then i installed "linuxcnc_2.9.3-amd64.hybrid" same problems as before+ expkey signature not valid due to age, but that's ok ish.. . I think there are a "update" being loaded on install or right after that bugs it. .
one thing i don't get also is when i installed 2.9.7 first time it showed Debian 13 with "red theme" ??
...... i think i will put the install on pause for some days because i am going insane lol .. thx for helping

Now added to my mirror.

The offical download site should really have the md5 or at least some checksum for all the files.

The files on my mirror are identical to those on linuxcnc.org/iso though only 2.9.4 (Bookworm), 2.7.14 (Wheezy), and an rPi version are available from my mirror.

I'd be tempted to try setting C007 to 14, but it will spin the motor opposite.

Hello community!
I have a Mesa 7i76e running, the wiring is correct except for the alarm loop. Using a Lenovo ThinkCentre M910q with i7 4-core, 256/GB NVMe SSD, i7 16GB RAM WLAN Intel Core i7-6700T 4x 2.80 - 3.60GHz with Linuxcnc 2.9.4, Probe Basic V.5 on Debian 12. No latency problems.

Once again, I'm here with a big problem. My DIY milling machine (1000x500x220 with aluminum profile frame, 20mm HGR, 1605 ball screws, 3 axes, 2x OMC Stpperonline 400W integrated servo, 1x JMC CL Stepper 3.5Nm, set 2000 steps/rev) is now mechanically finally assembled. I also got a lot of help from this forum in setting up LinuxCNC, eliminating latency problems and spindle control problems, but now I have a milling problem that I can't solve.

I have milled several test parts with drill holes, 2 circular pockets, and a rectangular outer contour, and have noticed that my circular pockets are becoming elliptical. The deviations in Y are approximately +0.35 mm at 45° and approximately -0.38 mm at 135°. The X values for the rectangular contour are perfect to within 0.01 mm in X and 0.09 mm in Y, X I consider to be acceptable, but Y is over tolerance. However, the circular movements contain deviations I cannot tolerate. I will show you a photo of the last test piece. After each individual test part, I made changes to rule out certain things.
The first change was to replace a simple Chinese C7 ball screw with a ground C5 spindle with double nuts. This reduced the originally even higher values by almost half. However, the deviations described above remained. After the next test part, I replaced the 400 W servo with a 3.5 Nm JMC CL stepper motor. The results remained almost the same. As a final attempt, a few days ago I replaced the spindle's fixed bearing with a new one, with 7002AC angular contact bearings in an O-arrangement with a 1 mm spacer ring between the outer rings. I inspected the previous fixed bearing and found no faults. There was a 1mm spacer also and the O arrangement was the same.  I had also taken measurements at the spindle end earlier and actually and found no backlash.

Yesterday, moving away from mechanical faults, I noticed a difference in the motor definitions for the X and Y axes in the .ini file. The Ferror and min_Ferror points differed by one decimal place. X was set to 0.1 and 0.01, while the Y axis was set to 1.0 and 0.1. After I corrected this difference, the motor on the Y axis went into alarm mode after a few position changes.

What could be the reason for this? How can it be that one motor runs perfectly with much lower tolerance values, while the other quickly goes into alarm mode with less load? The motor in question has the same power supply and is certainly less demanding in terms of starting currents than the servo on the X-axis. With the higher tolerance values, the Y motor runs without alarm, but has these deviations. Are these tolerance values in the .ini file responsible for these deviations?
The mechanics of the Y and Z axes are flawless, as checked with a dial gauge, and the repeat accuracy is also very good, less than one hundredth. 
Do you have any ideas about this? Where can I look further?
Thanks for your time and hints    

 

I tried
C07 --> 2. The VFD no longer started the motor.
C07 --> 1. Same behavior as CO7 - 0.

Terminal E3 and E2 are unpopulated, but always have been. In the video link above, it was ramping down when I first tested it, and I am pretty sure I found a way to turn that off.
C007 is assigned option 0.

Sorry, meant C007. QSB is not selected by default. Default is DC braking. Page 7-78.