Dual Manifold Pressure

JohnSpratt

New Member
Joined
Apr 18, 2005
Messages
4
Location
KMEV, Minden-Tahoe Airport, Minden, NV, USA
Dynon,

Question: Can a second Dynon manifold pressure sensor definition be added to the Skyview Sensor Mapping page? If so, how is it accomplished?

ans:


Only pin 26 on the SV-EMS-220 C37 has that input and definition on the sensor input mapping page below. None of the other pressure capable pin positions had the Dynon manifold pressure sensor, p/n 100434-000, listed in the sensor list.

Thanks,
John Spratt
 

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dynonsupport

Dynon Technical Support
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Mar 23, 2005
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13,226
Not to contradict my colleague, but I will, because it's fun ;)

You can actually run two MAP sensors if you edit the sensor config file. You can use pins  8, 22, 23, or 31 for a second MAP sensor.

Attached is a sensor file that will allow that.

Just note that the system only uses the one named MAP for things like % power, and you can only name one MAP so the second one needs a custom name spun in,
 

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JohnSpratt

New Member
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Location
KMEV, Minden-Tahoe Airport, Minden, NV, USA
Thank you for the help. Having dual manifold pressure readouts  available on the Skyview display will simplify the 100 hour requirement for the Rotax pneumatic carb synchronization checks for the 912/914 engines. By using hose pinch-off pliers at the rubber connector on the crossover tube to separate the manifolds the display will give a separate reading for its manifold. If they are the same, I am done. Without the dual readings a manifold pressure diagnostic tool with dual gages or dual digital readouts is required. The dual Dynon MAP sensors installed will provide continuous carb synchronization readouts. Pictures and a part number are included below for others that might be interested in this.

Sincerely,
John Spratt
Repairman Light Sport Aircraft #1911891
Rotax Heavy Maintenance  # 140001120219-05
Repairman Experimental Aircraft Builder #3176967

Rotax 912 (80hp), 912S (100hp) and and 914 (115 hp) engines have two separate intake manifolds joined by a crossover tube.



Each intake manifold has a 6mm threaded hole next to where the crossover tube connects. An Mx6M hose nipple, Rotax P/N 940 558, can be used to connect a manifold pressure sensor to each manifold.

The crossover is typically connected to sense the manifold pressure average of the two manifolds and display manifold pressure in the cockpit. With a manifold pressure sensor on each manifold, the carburetor  synchronization process is simplified by using hose pinch-off pliers at the rubber connector on the crossover tube to separate the manifolds, then read the separate manifold pressures on the cockpit display.
 

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  • 60683CrossoverTube.jpg
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JohnSpratt

New Member
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Apr 18, 2005
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Location
KMEV, Minden-Tahoe Airport, Minden, NV, USA
The modified sensor_map.sfg file was loaded and allowed the second MAP sensor to be input on pin 31 and named "MAP R", however, the pressure for it had psi for units rather than inHg. It also displayed a value with no sensor wired in. How can that be corrected?
Thanks,
John
 

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dynonsupport

Dynon Technical Support
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John,
The units issue can't be corrected without a software change. You don't have a way to make individual sensors different units (you can't show oil pressure in kPa and fuel pressure in PSI). We have a special case to allow something named MAP to be in a different unit, but this won't apply to MAP X.

As for the value floating, that's a side effect of our general purpose inputs instead of the specialized MAP input. If you want to fix it, you can run a 100K ohm resistor to ground for that input.
 
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