I am trying to program some performances so that my Yamaha CV pedal controls the volume of individual parts.
When I choose a Part Volume, hit the Control Assign button, then move the pedal it creates the control assignment for that part.

However, that's when I realized that the pedal has a global volume control over all parts.
How do I turn this off?

On some parts I will want to use the pedal to bring in LFO, or control the filter, volume, Leslie, etc.

Because you want to select different functions based on the individual Part you are addressing - you want to avoid using a universal MIDI command.

From your Performance HOME screen:
Press [EDIT]
Touch “Control” > “Control Number”
Set “Foot Ctrl 1” = 4
By choosing a Control Change number that does not have a universal assignment, you get to choose, on a Part-by-Part basis, what the FC1 is set to control. If you leave it to the default, cc11, then it will always control Expression (performing volume) even without an assignment. By selecting cc4 *you* get to decide what the FC1 does in each Part.

CC4 does not have a fixed function like cc11.

I also noticed that when I went into a part that I didn't want to be affected by the pedal and turned off the FC1/2 receive switches, it had no effect. The pedal still controlled their volume.

If you set Foot Controller 1 to cc11 Expression, it controls the Part’s output level even without assigning it in a Control Set. That is a global assignment throughout MIDI.

CC4 is “Foot Control” — you decide in the Part Control Set what this addresses.

...when you turn the “Receive Switch“ OFF for FC1 anything programmed to the FC is prevented from being received, unless of course, it is one of the two global MIDI commands for volume: cc7 or cc11. They work universally throughout MIDI without any assigning. Therefore, they have their own Receive Switch.

Notice the separate Receive Switch that addresses just CC7 “Vol” and CC11 “Exp” __ “Vol/Exp” On/Off
If you do not want a Part to respond to cc7 or cc11 you can set this Off... now no matter where the command originates, the Part will not receive these commands.

Extra Credit:
CC7 is Main Channel Volume
CC11 is Expression
CC7 is like the volume slider on a mixer - controls the overall volume of that channel.
CC11 is like the volume control on the instrument, before it goes to the mixer. It is your performing loudness.

If the Mixer slider is set to 99 that’s cc7, the Foot pedal set to send cc11 would be 0 in heel down position and 99 in toe down position.
CC11 works within the main volume setting set by cc7.
It’s the same as: the instrument plugged into a mixer channel works within the volume setting for that channel.

AWESOME! So as far as volume is concerned, it looks like the easiest thing to do is turn off the vol/exp receive switch for the parts I don't want control, and just allow the other parts' volume to be controlled by the normal default setting. (Which I just tested and it does what I wanted).

And then to assign the foot pedal to something else in another performance, refer to the MIDI CC chart and pick an undefined control number.

Thanks!!!!