Interfacing Haas 5C indexer to ALLIN1DC

[CRM]

UPDATE:
I disassembled the motor housing of the indexer to better understand the wiring. Haas uses a connector block on the servo end that, to eliminate coolant ingress, is completely potted to encapsulate the 4 Molex plugs that terminate the cable, breaking it out into the 4 components it connects to: a 10 position for the encoder, a 4 position for the 3-wire prox switch that senses home, a 2 position for brake (not used in my indexer) and a 3 position that connects the two leads of the servo motor. The other end of the cable has a 17 pin Amphenol connector molded to it. So, I can't physically see wire colors or connections at either end without destructive disassembly.

I checked each pin on the 17 pin Amphenol connector for continuity to every pin on every connector on the other end. So now I have the topography of the cable. What I learned was that the prox switch takes +5vdc from the same pin that powers the encoder. What I DON'T know is whether that prox switch is PNP or NPN because there's no visible markings on it and there is no real good way to identify it with a multimeter according to Google. My ALLIN1DC is configured for SINKING inputs. It is my understanding the prox switch must be NPN to work in this case. Let's assume I luck out and it's indeed NPN.

HERE IS MY QUESTION: Will it work to be drawing the +5vdc for the prox switch from the +5vdc pin of the encoder input, or must the prox switch be powered from the common terminal of the inputs on H11? (I intend to use INP7 for the "A" axis home switch) If it can come from the encoder, does the 0vdc lead of the prox switch go back to the encoder ground and only the signal (load) lead of the prox switch go back to INP7? My gut tells me that WON'T work (or at least it is bad practice), because I am trying to sink current from a power source in a different section of the ALLIN1DC than it originated.

If I can't do that, my only alternative is to alter the wiring in the indexer to separate the power sources for the prox switch and the encoder and repurpose the brake circuit pins in the Amphenol plug for the 2nd power source. I was trying to avoid that so that any Haas indexer would plug into my Centroid without modification.