Add 'INF' status to TTG for BMV

[eriksnijder]

I have a dashboard with my BMV712 data to (remote) monitor my sailboat. When connected to the battery charger the dashboard shows -60 which suggest that if the TTG is INF (as displayed in the BMV) the value of -1 is provided.
I would like to propose to add the following lines to the field.js file after line 226:

else if ( value === -1) { return 'INF' }

Regards, Erik

[sbender9]

Returning null would make more sense. This field is a number, it should never be a string.

[sbender9]

Also the venus plugin sends null in this case.

[eriksnijder]

I'm fine with that, as long as my dashboard doesn't show -60