RPM not working

[iceman]

Hi...Just ran my Rotax 912 UL engine for the first time. Everything works except the RPM reading. What could be wrong ? Do we need any special converters for the D120 to read the RPM signal ? Please help anybody ?

 

[Simn_Smith]

As long as it is connected as per the manual (using the resistor) it should work. It might be worth checking that the line that you have connected it to (RPM L or R) is the one that the D120 is trying to display.

 

[iceman]

Hi...thanks for the reply. We are connected to the left one. I also set the sensor to read left under the setup. What should the voltage output be after the resistor ?

 

[iceman]

Dynon support please help !!!!

 

[dynonsupport]

It's pretty simple, just as the install manual says:

Hook one end of the trigger coil to ground.

Hook the other end to one end of the 30k resistor

Hook the other end of the resistor to the EMS L RPM input.

That's it. It should work. The voltage after the resistor should be a very fast 10-100V pulse. You'll only be able to see this on an oscilloscope.

There is no setting in the EMS to "Read" the L RPM input- it's automatic. Are you sure that you're setting up the right thing? The only setting for RPM is if it's displayed, and what the pulses/rev are. If you want, you can try to hook the RPM to the right tach input- it works exactly the same.

 

[iceman]

;D Hi...Great to have you guys back. I was so badly wanting to fly my aerie but cant until I have sorted these issues out. Okay I follow what you say. Let me give it another bash and see what is going on. What is the purpose of the resistor ?

 

[iceman]

Hi...got it to work. We were using a common ground between all the instruments in the aircraft. What we then decided to do was put in a ground seperate from the other instruments the would run directly between the engine and the D120. It worked. Thanks for your input.