How to write an Input PGNs / Help with Autonnic Windex

[Sailormatt]

Hey all, could someone point me in a useful direction? I have an Autonnic masthead wind instrument; I had to place it off-centre because of the masthead setup—my wind instrument is now offset from the centerline and not pointing directly forward.

I only have a one-page instruction sheet for the unit (attached) it states:

Input PGNs Custom (PGN: 127257). A 6-byte block of which only the first is used as follows: Set Wind Heading to Zero = 7

Is there a way to use SignalK or something in OpenPlotter to do this? I have Open Plotter running on a Pi-4 and an Actisense NGX-1 connected via USB to the N2K network. Alternatively, I have Raymarine E-series plotters, but I don't think that is possible with those.

Many thanks in advance for any pointers

Regards

Matt