Nixie x MEGA-BAS (v4) RS-485 communication issue

[craywm]

Hello all! I've been researching Pool automation the past few seasons, and late this season decided to pull the trigger on the Nixie standalone controller. I decided to begin late in the season instead of in off season due to my pump beginning to overheat, and replacement seems immanent. I started slow with a proof of concept, and ordered my panel BOM to begin building my outdoor station. Here's my pool info:

Body Specs:

Location: Lexington, KY (May - Sept season)
Capacity: 16,500 gal
Automation: None
Pump: Hayward Superpump 3/4 HP
Filter: Hayward 300lb Cap. sand filter
Sanitation: Pentair IC40 with PC100 power station

Nixie Standalone Pool Controller specs:

Processor: RPi 4 model B (8GB)
DAQ/COMM: Sequent MEGA-BAS (must be V.4)
Power control: Sequent 8-RELAYS (v.5)

Peripheral

Temperature: 10k Pool temp sensor (for testing - will add more in future)

Issue back ground:

I setup the raspberry Pi, and installed REM, Dashpanel, and pool controller to the RPi. Everything fired up and was straight forward. The last step before I pulled the trigger on the full panel was to test the RS-485 communication to the salt cell. The interface I initially used was communication through the MEGA-BAS RS-485 pass through. This was not successful (not setup in chemistry) so I ordered a physical USB RS-485 adapter. I wired the USB adapter onto a bus with the MEGA-BAS RS-485 connections. This is where things got... weird.

Nixie is using the dev/ttyS0 for RS-485 communication. Since I wired the USB adapter on the bus, I set dev/ttyUSB0 as the Aux port, and adjusted the chlorinator port in chemistry for testing. After attaching the USB adapter, communication began immediately through the ttyS0 port, and worked very well. After confirming that the ttyUSB0 port was unnecessary, I removed it and restarted everything. There was no communication when I restarted with the chlorinator. Thinking it was a wiring issue, I replaced wires, reseated them and restriped many times to no avail. I decided to re-create the original setup and it fired right up. This time, I decided to manipulate the communication from the COMMs side. I left only the ttyS0 as the primary, and installed the USB adapter to the pi, and wired into the RS-485 bus. The ttyUSB0 was not setup in dashpanel. I started everything up, and communication began to flow through the ttyS0 primary port.

This is where I thought I had success (maybe just a lose wire that was finally corrected), so I removed the female mating connector block from my USB RS485 adapter, and communication stopped. I then re-inserted it, and removed the USB from the RPi. Communication stopped again. Thinking maybe the Pi devices were mapped incorrectly, I decided to remove the female mating connector from the MEGA-BAS (disconnect RS-485 from MEGA-BAS), and again communication stopped. I was very confused by this. I setup a Aux Port for the USB adapter and setup an additional IC40 fired it up and both IC40 communications began to work.

It appears that the USB adapter must be plugged in for the RS-485 to work from the MEGA-BAS. I should have taken screenshots..
Anyway, I figured I had installed something incorrectly, so I performed a backup, reflash, and reload on the SD card, reinstalled everything (decided not to use the USB adapter), and I still cannot get the MEGA-BAS RS-485 pass through to work. I think some other members had similar issues (#581/#804).

I tried to troubleshoot on my own, but dont know where to start for the RS-485 communication. I've narrowed it down to a possible problem with these newer MEGA-BAS versions, or some silly error I made during setup. Here is a replay as well:
replay.zip

Has anyone else dealt with an issue like this, or know where I can start troubleshooting?

[craywm]

Also, here is a replay with the USB adapter installed and A+/B- connections attached to the bus. No changes were made to the communication configuration in dashboard.

replay (1).zip

When I plug the USB adapter in, like magic the RS-485 port on MEGA-BAS works. I would prefer not to run with a USB adapter. I assume if the MEGA-BAS RS-485 isn't working, that the 8-Relays RS-485 wont work either (Must be on Pi side).

Any help/direction would be greatly appreciated!