Hi Thomas,
Maybe by answering your second question first, we can shed some light on the subject.

Using PLG150 Voices in a MIX
The Motif by itself (using just the internal sequencer) is capable of 16 Part Multi-timbral operation. The PLG boards have their own polyphony and are basically separate synthesizer engines that will use the host’s hardware. Before you expanded the Motif with PLG boards, the 16 Parts of a MIX were always occupied by internal sounds. When viewing the MIX screen you are looking at PARTS 1-16 in the MIXER.

• Press MIXING

Once you have installed your PLG 150 board(s) you are able to toggle between viewing and editing the internal PARTS 1-16 and Boards PLUG-In slots PLG1-3 via the [F6] button.

Press F6 now, and get used to switching the view from 1-16 (Internal) and PLG1-3 (Plug-in slots 1-3).

What you are going to do when you want to assign a PLG sound is either layer it with or replace one of the internal Motif sounds. As we stated, by default (when you first call up a new MIXING page) Parts 1 through 16 are occupied by internal sounds assigned to MIDI channels 1-16. This is quite natural and basic but must be stated because what you want to do now that you have PLG boards is decide what MIDI channel do you want to address them.

The PLG boards default to MIDI channels 1, 2 and 3 when you place the board in slot 1, 2 or 3 respectively. You can reassign them to any MIDI Channel, as necessary. It is guaranteed that whatever MIDI channel you choose will already have an internal Motif sound assigned – all 16 channels are currently used. If, for example, you want to place your PLG150 board on MIDI channel 10, you will need to make a decision. “Do you want it to share the MIDI channel with the current sound assigned to MIDI channel 10? Or do you want to replace the MIDI channel 10 sound (the sound on PART 10)?” The reason it does not automatically replace the internal sound is because you may want to layer or split a PLG150 Board sound with an internal sound at some point.

Replace it:
If you want to replace the internal AWM2 sound, you will need to know how to assign the PLG150 Part a MIDI Receive Channel and then deactivate the MIDI Receive Channel on the internal sound assigned to the selected MIDI channel. (This will require that you drop into MIXING EDIT and that you are comfortable toggling back and forth via the [F6] button.

Setting the PLG slot to a MIDI channel:
• Press [MIXING]
• Press [EDIT]
• Press TRACK [1] to select PART Edit
• Touch the [F6] button to toggle to PLG1-3 view. The Parts are labeled PLG1, PLG2 and PLG3.

• Select the Bank and sound Number that you want to use. It is very important to select a bank associated with the PLG board type in each slot. If you have a VL Board in slot 1, only PLG150-VL Voice Bank can be respected via slot 1.
Select the board’s “PLG PRE1” bank and Program Number 001.

• Select [F1] Voice/ [SF2] Mode
• The Receive Channel for a PLG150 series board in Slot 1 defaults to MIDI Channel 1.
The Receive Channel for a PLG150 series board in Slot 2 defaults to MIDI channel 2.
The Receive channel for a PLG150 series board in Slot 3 defaults to MIDI channel 3.
You can, of course, choose any MIDI channels, as you require.

When the Receive Channel is set to channel 1, the PLG1 sound will be “layered” with the Motif internal sound(s) associated with MIDI channel 1 (PART 01 by default). To turn off the internal PART 1 sound you must un-assign the MIDI Receive Channel:
• Touch the [F6] button to toggle to the internal 1-16 view.
• Select [F1] Voice/[SF2] Mode

• Set the Receive Channel of the internal PART01 to OFF.

You can now play the PLG150 sound “in place of” the internal sound.

Note: If you had assigned the PLG board to MIDI channel 12, then you would go to any PART set to receive on MIDI channel 12 and deactivate its MIDI Receive channel, thereby replacing the internal sound with the PLG sound. And you would need to transmit from a track assigned to MIDI channel 12 to play the PLG150 sound. Try this as this can be tricky. Up until now the PART you have selected and are viewing in the screen always coincided with the PART you heard. But with PLG assignment this can be different.

Ok - so the PLG150VL starts by sharing a MIDI receive channel. Its up to me to decide with whom (another internal voice) or I can give one or the other an exclusive. Are these assignments I have to make or change every time I start creating a new pattern? In other words,will the PLG voice will always begin as a shared voice on one of my 16 pattern tracks? If so. can I have it default to "Silence" that way even if its sharing, I wouldn't hear anything. Right now it always starts as a trumpet sound on track 2 in my mix whether I want it or not. (My PLG is in slot 2) Is it a better practice to turn off the PLG receive channel altogether whenever I don't plan to use a PLG voice in my pattern mix?

Yeah, I remember dealing with something like that. It's been more than 12 years since I last had hands-on an ES. But I remember you can simply place the PLG150 Boards on a different Port until you want to use them. Go to UTILITY > [F6] MIDI > [SF2] MIDI > set your PLG Boards on Port 2. This will remove any possibility of them being able to communicate with the internal engine. Port 2 would be used when addressing the Motif ES via USB (or mLAN) from a computer... the PLG150 Boards could all be placed on three channels of Port 2. By here, placing them on Port 2 removes them from being accessed by the internal engine which is used when Port = off or 1.

Thanks so much Phil....just to summarize / clarify - if I follow your instructions, I can turn OFF MIDI receive for an internal voice assigned in Pattern Mode to tracks 1-16 and replace it with a PLG voice, Correct ? Can I then use the sequencer to record MIDI data to playback and loop my PLG voice in a pattern just like I can with an internal voice?

Absolutely!