Weird. I was right all along. !!!

After powering the IO board on and off, the SDO's are set to zero.
Restarting Linuxcnc again in this state linuxcnc opens without reporting any errors.
But if you close Linuxcnc and restart it, it reports errors on all of the SDO's.
I've never seen that before.
 

Thanks for the help. At least I can proceed to actually test on the spindle now!

I also set them in xml. But troubleshoot and experiment on the command line.

answer no they don't

I've always set the SDOs in the xml
So I had a play when I worked out I needed to use 0x3000 and despite all of linuxcnc's complaining, the entries were set correctly.
Do SDO's persist on power cycles?
 

Solved.

Short answer(s) for anybody in the future reading this:

1. No, do not need to change (INI_FILE_NAME)
2. Yes, yes, and I no longer care what "catch" does.
3. Yes.  You can just write each hal command line out in a readable form.
4. Yes, the way it's written permits changing "x y z" at the top and everything below gets sorted out.  Clever, but miserable for us Luddites to unravel.

Strange. If it's in the sdos listing I have always been able to read the value with
ethercat upload -p 0 0x3000 2
for example.

yeh, I tried 0x3000 and had no more luck (it is a hex value)

0x3000 perhaps? Try upload to read the register.

Apparently not. Looks like I have to lug a spindle into my office. Is the syntax right?

Does it work when you set the values with ethercat download/ethercat upload?

I'm trying to set the catio-a I/O module to talk to a VFD via Modbus but I am at a bit of a loss.
Excerpt from Ethercat sdos
I got this for the xml file but I get errors reported but eventually axis opens without any syntax issues with 
Failed to Execute SDO download size 1, byte0=0 error -5, abort code 06010000
subIdx 0 = read only
subIdx 1 is a PDO so no need to set in SDOs, PDO definition works
SubIdx 7 is a error count

If you have ideas, please have a go.

Would the VFD need to be connected via rs485? I have not done that yet.
 

I have this pendant and would like to test out your firmware. Where do I find it/install it from? I'm tired of this device working and then just deciding to quit working in the middle of operations.

Firmware for a 7I95T with 2 RC PWMgens replacing the last (05) step/dir pins:

 
 

I'm going to make a list of components grouped by:
Power (From source to when it get's used)
Inputs (Not much here, keyboard and the handheld)
Motion (From the controller to drives to servos, incl encoders)
Feedback(All other sensors)
Spindle(VFD and everything downstream of it)
Other shit (ATC, grease, beer bottle opener etc)

Lot's of great feedback here. I'll try to understand everything said before committing to a plan. I've been labelling wires. Also decided to simply move to fuse out from the main junction box into its own separate box and just add another half-in conduit just for carrying power to the main box. This frees up all the room I need in the main junction box to work. I think I will be adding an additional 1in conduit to carry the extra conductors needed for the swivel head and rotaries.