Welcome to Yamaha Synth!

In general, you can assign physical controllers of the XF7 to Destinations in your external module EX5R. The EX-synth engine had an unprecedented number of parameter destinations and Control Sets to work with. The keyboard version (EX5) featured some 13 Physical Controllers and the multiple synthesis tone engine had almost 150 Destinations within a Voice. And while you do not have as many dedicated physical controllers on the Motif XF, you can re-task Knobs and Sliders to make up for it within the XF's flexible Master Mode.

What you need to know about your keyboard controller is the cc (Control Change) number it sends for each of its physical controls - then setup your EX5R accordingly.
MW(01), RB(22), FC2(04), AS1(16), AS2(17), AF1(86), AF2(87) etc.,

MIDI provides for controllers that send zero through one-twenty-seven (0-127) and others that go north-south of a center point (-64~0~+63), it also has parameters that respond minimum-to-maximum (like volume) and others that go above-and-below a center point (filter Cutoff). As long as you are aware of this and assign your controllers with this in mind, you should be able to accomplish most anything.

Within the EX5R's Voice architecture, assignment of physical controllers are handled similar to the Motif sound engine - that is, there are a number of Control Sets (16) where a Source (physical controller) is assigned to a Destination (parameter), with a Depth amount (degree of control). So what you assign could be doing one thing internally (to the XF7) and something entirely different externally (in the EX5R), on a per Program basis. This is because you will not be changing what the physical controller sends (as far as the cc message number), your programming will be within the VOICE architecture of the receiving tone module - what parameter Destination you choose to control and by "how much" (Depth).

You will want to study the special features of the EX5-engine - for example, the ability to "morph" between any two SCENEs is not only powerful but a compelling feature, particularly with the modeling synthesis engines. Basically, you have a starting point and a finish point - the SCENE functions will create all the parameter changes necessary to move from one sonic place to the next. The MW2, was a 0 through 127 control, with a center point; making in the ideal controller (on the EX5 keyboard) to "morph" between Scenes - you will need to use a CONTROL KNOB to get the same center mark... but you should find making and controlling parameters on the EX5R a wonderful experience in synthesis.

Motif XF Master Mode
Using the Motif XF7 Master mode, you can assign additional Knobs and Sliders to a single ZONE (if necessary). By default the Motif XF Master mode has 8 ZONES (a Knob and Slider for each). However, nothing says you have to use all 8 Zones separately - you can take the knob and slider from a ZONE you are not using and re-task it in a ZONE you are using. (The trick is to assign the NOTE LIMITS so that the Low Note Limit and High Note Limit are at extreme *opposite* ends - so that you only trigger the ZONE from one set of Zone parameters).

So for example, if you want to assign 4 additional Knobs and Sliders to control the EX5R, you would set one ZONE's Note range parameters to trigger the KEY RANGE properly. You would set all other ZONES assigned to the External EX5R so that Note Limit Low = G8 and Note Limit High = C-2. This would prevent that ZONE's keys from playing the EX5R, yet allow the KNOB and SLIDER of that Zone to be used with any cc Number you decide to use.

There are simply too many possibilities for us to outline here - it will all depend on the sounds you select, what you desire to control within that sound and how you wish to perform it!

The EX5R is, without much doubt, one of the most powerful rack modules ever made in MIDI, period. Have fun! Please post some of the things you come up with! If I find any of the articles I wrote 15-16 years ago (on the EX engine and controller assignments) I'll send them your way!

What an excellent comprehensive response! Many thanks, and I will certainly post back with my experiences.