Thachometer back up

[JulianoMaiaLopes]

I would like to connect my D-180 and "Electric Rotax Tachometer" as a back up. The engine is a Rotax 912S
In FlightDEK-D180 Installation Guide the instruction is to connect either of the two wire to ground and other to one of 30K Ohms resistor.
My ask is: if I connect one wire to ground RotaxTachometer still run?
How I can connect both instruments?

 

[josok]

Yes, the Rotax tach will still run. The same tacho in the 914 installation has one of the wires grounded in the TCU. So basically connect the tacho as per Rotax diagram, ground one of the wires, and pick the pulse off the other wire with the 30K resistor.

Regards,

Jos Okhuijsen