Tach input to G3X from PMAG

[Webb]

My schematics were drawn with a UMA sensor on a slick mag. Instead of slicks, I will be using dual PMAGs.

Please tell me if this is correct…… The UMA sensor is deleted so the 12v input from the GEA24 is not needed and Garmin doesn’t require a diode.

 

[Southern Pete]

What about J243 pins 8 & 6? Read section 23.4.8

 

[lr172]

Definitely read the manual. Most cyclic/on-off transducers sink the sensor lead to ground in rhythm with the cycle, whereas the tach signal is a +12v signal that makes a square wave, by changing from 12 -> 0 and back, in rhythm with RPM. The manual will tell you where a tach signal should go and how to set it up.

 

[Webb]

What about J243 pins 8 & 6? Read section 23.4.8

What about J243 pins 8 & 6? Read section 23.4.8

Manual says second source can be used and it will display the higher of the 2 values. However, schematics in the install manual show only one input for pmag (one wire shielded) so it looks like the only connection will be signal (pin8) from a single mag to the GEA24.

 

[Desert Rat]

Manual says second source can be used and it will display the higher of the 2 values. However, schematics in the install manual show only one input for pmag (one wire shielded) so it looks like the only connection will be signal (pin8) from a single mag to the GEA24.




View attachment 54275

Webb, Per the Emag manual, you only need a tach input from one Pmag because the tach signal will still transmit even when you select that mag off during the run up.

 

[Webb]

Thanks Terry. I haven’t gotten to the mag manual yet. I also need a few more feet of shielded wire and just trying to figure out my order so I can only incur one shipping charge. LOL.

 

[Southern Pete]

Shielded wire isn't required as it is only a low power signal.
Connect one Pmag to pin 6 and the other to pin 8 - its all in the manuals - ground return is via airframe ground.

 

[georgemohr]

We connected both mags to the GEA24 for redundancy.