Dual Xtreme EFIS

[Hitchflight]

Have been the happy user of an MGL Xtreme EFIS (2nd generation model) that I fitted a few years ago.

Following a vacuum failure last month I decided to remove all analogue instruments. After a complete panel redesign I fitted a further MGL Xtreme EFIS (this is the latest 3rd generation model). For good measure I also fitted a third EFIS with UPS. The third device is totally independent and not relevant for the discussion, but does provide an accurate datum.

Each Xtreme EFIS unit goes back to the single RDAC. Each accessing the magnetometer and AHRs.

All works brilliantly.

Please note the OAT probe is plugged into just one EFIS.

All the EMS and EFIS functions are working fine! Except a couple of niggles. (Notwithstanding one screen quite reasonably does not display OAT because it isn’t receiving a signal.)

Niggles I’d like to address.

1. There are different indications of IAS
2. There are different indications of altitude
3. Wind speed and direction is well out.

Is the mismatch is caused by having just 1 x 120ohm R at the splitter, or no OAT on the other MGL, or both?

Thoughts?

Regards

Bob