Multicell fixtures?

Yes.

Most likely multi-LED fixtures that abound in Rock & Roll today like the Robe Spiider.

but also film lights like Spacelights.

In the theatre, you're most likely to encounter multi-cells in LED batons like the Colorforce series from Chroma Q or similar.

 

Check out ETC's Youtube video on v2.7 for programming details.

Yes.

Most likely multi-LED fixtures that abound in Rock & Roll today like the Robe Spiider.

but also film lights like Spacelights.

In the theatre, you're most likely to encounter multi-cells in LED batons like the Colorforce series from Chroma Q or similar.

 

Check out ETC's Youtube video on v2.7 for programming details.

Oh OK. They sound just like regular simple RGB LED lights that you need three channels for, but the Robe Spiider had a whole heap more. But what confused me is that the manual goes on to talk about Moving Head lights! Again, to me these are like the RGB LED but have other channels for Pan, Tilt etc. Really down to earth I think you can control any multi DMX address device with the faders. Not so efficient but it can be done. In some cases you have to use different parts of the 0-256 data range to do things. That's why I like ETC boards when I can plug in an exact DMX add AND value to get what I want.

Not on Ion.
Each fixture uses 1 Channel. but that one channel can control multiple attributes such as Red, Green, Blue, Pan, Tilt, etc.. You do not need to patch 1 address to 1 channel as you would on Express.
It may seem as if it's less efficient, but it's better organised and that allows you greater control.

A small LED we have uses CH2 Red, CH3 Green, CH4 Blue - all 0 to 100%. But we have CH1 that is split (as best I can describe it) into zones. I.E. CH1 at 0 = Off, 1-127 = 0-100% Intensity, 128-250 = Strobe, 251-255 100% Intensity.
And normally we would give this one channel. But we would put in #'s from the keyboard to control the attribute within CH1. Would CH1 therefore be a "Multicell"? We have a King Kong 1024 in the other theatre which has an attribute section whereby these channel 'zones' are broken out onto individual faders or wheels. Is this what we are looking at here? It's hard to put into words.

That is a standard Control Channel. Many lights have those. (Although that configuration seems really weird.)

This is a Control Channel interface for a Martin Mac III. It's accessed via the Lamp Controls tab on your console.

Hmm! above my pay grade at this time. The Martin Mac III from what I read requires 30 DMX channels for 16b extended. I can't really relate that to your picture. However one puts it a lamp like this with a starting (base) DMC address of say 012 would take up all addresses 012 thru 042. Some of those channels (the 3 extra) would be 'partners' used together with another channel to provide 16bit resolution for smoother operation. Back to the book!

I dont think your point above really got answered

A small LED we have uses CH2 Red, CH3 Green, CH4 Blue - all 0 to 100%. But we have CH1 that is split (as best I can describe it) into zones. I.E. CH1 at 0 = Off, 1-127 = 0-100% Intensity, 128-250 = Strobe, 251-255 100% Intensity.
And normally we would give this one channel. But we would put in #'s from the keyboard to control the attribute within CH1. Would CH1 therefore be a "Multicell"? We have a King Kong 1024 in the other theatre which has an attribute section whereby these channel 'zones' are broken out onto individual faders or wheels. Is this what we are looking at here? It's hard to put into words.

This is not multicell.   A multicell might be something like 6 seperately controllable RGB lamps on a single moving head mechanism, or one of the circular LED washes that the individual LEDs can be controlled separately.   Until multicell support was added in 2.7 you'd have to setup each RGB lamp in a multicell as a separate channel,  now they can be thought of simultaneously as both one single channel (so 123 out would turn it off) or as the seperate cells (so 123.2 out would turn off cell two), making it a lot easier to work with.

The thing you have got where a attribute on a DMX address is split into zones is what has been around for a long while.  Patch most fixtures and if you select it in the ML control tab you will see this kind of setup,  often in the colour bit of an LED lamp you'll see a set of presets (maybe white colour temp for example) or strobe modes etc. And they are setting a dmx address to one of a range of values.

Your fixture is a little unusual in splitting the intensity like that as it means you can control the intensity when in strobe mode, but its perfectly patchable to work like that.  (and maybe that's what you mean by we would put in #'s from the keyboard to control the attribute within CH1)

Ah! Excellent. Makes more sense this way. Well, happy to say that having beaten the heck out of this forum and making pile of notes, I feel I've left the 1 to 1 universe (pun absolutely intended) and am now much more comfortable then a week ago.