Difference between two gauge values

Apologies if this is obvious and I simply missed it, but I am trying to display some sort of visual indicator if the value of Gauge X and the value of Gauge Y are too far apart. More specifically, I am using MegaSquirt, and my entire dashboard is just a display of AFR and the AFR Target. I want a warning light if the AFR strays too far from the AFR Target (i.e. too rich or too lean). Is this possible?

This is possible with Gauge Math in Look & Feel->Special->Gauge Math. In Gauge math you can reference other values by id.

Thanks for the quick response, I think that will be exactly what I need. Can you provide a simple example of the Gauge Math syntax? I can’t seem to get it to work. I don’t think I am referencing the other values properly. Thanks.

See list of ID:s here:
http://realdash.net/manuals/targetid.php

For example

=ID0>ID2

Produces value 1 if AFR1 is greater than AFR Target1, otherwise it produces value 0. Then you can use this value to lit up a indicator or something else.

That worked great, thanks for the help.