MGL RPM instrument on Jabiru

[stuartmspencer]

I've just fitted an MGL RV3 RPM instrument in my J160 to replace the VDO instrument that appears to be under reading. I attached the pulse input to one of the alternator wires as advised by the supplier. I get a good readout apart from when I switch the strobe light on (and to a lesser extent the fuel pump) which causes it to go crazy. Clearly both of these produce pulse interference but I'm wondering if there is anything I can do to eliminate this? Unfortunately I can't use the hall-effect sensor as it does not create a strong enough signal for the unit to detect it.

 

 

[cheyenne]

I have a MGL instrument fitted to my J160 reading EGT & CHT also, when I have the fuel pump on or the strobe the gauge reading bounce until turned off.

 

 

[Roscoe]

I have a MGL instrument fitted to my J160 reading EGT & CHT also, when I have the fuel pump on or the strobe the gauge reading bounce until turned off.

Mate can you elaborate a bit?

Do you mean the Bar readings on the MGL Bounce around and where in the Panel is the Instrument mounted.

 

I recently had the MGL TC-3 CHT/EGT fitted to my Jab on the RH upper panel with no issues so far.

 

 

[Yenn]

I have a TC3 fitted with no problems, but it is not a tacho. I have the MGL Flight 2 which I assume would be similar to the RV3 as far as connections go. Mine is connected to the Magneto P lead on a Lycoming and at best it is a guide to RPM and at worst it is useless.

 

I am not happy with MGL information, their manuals leave a lot ot be desired. You could try going to the MGL forum, can't remember its address but Google MGL and you will find it

 

 

[Yenn]

I have had troubles with MGL tacho in my Flight 2 instrument. Not happy with it but all the rest of MGL gear seems good.

 

You could try their user forum. www.mglavionicsusers.org

 

 

[Bruce Tuncks]

Stuart, there is a possibility that all your setup needs is a filter. This can consist of a few cents worth of components ( a choke, a capacitor and a resistor or 2.

 

Or you could consider an active filter which might involve a few dollars of op-amp.

 

You need an electronics nerd to design and make this up. Don't pay him till it works.

 

 

[ianboag]

I had a similar problem running an MGL tacho off the mags. I went through the (not very hard) exercise of setting up something similar to https://www.adafruit.com/product/2349 as well and that worked too .... phototransistor and IR source - pointed it at the flywheel and put a black stripe on it with a permanent felt pen.

 

Eventually I hooked it up to one of the alternator leads and that worked fine. Had to fiddle with the calibration factor as I recall. I don't recall why I changed it - was a long time ago in my pre-Rotax days.