Single sensor, two indicators?

[Chip Sylverne]

I have a VDO oil pressure sensor and guage in the panel. I am planning a JPI830 install. Since the 830 will provide a redundant oil pressure display, is it acceptable to wire the output of the sensor in parallel to both the existing I dictator and the JPI?
Obviously two pressure sensors is problematic.

 

[flyingron]

I have a GPI 830 and a MVP50 now. I was able to parallel most of the sensors between the two systems. About the only thing I did NOT do is the fuel flow (for no apparent reason I think).

 

[jbarrass]

I have 2 AV30's fed by one magnetometer. Not sure if that's entirely relevant.

 

[robin ardoin]

I have a GPI 830 and a MVP50 now. I was able to parallel most of the sensors between the two systems. About the only thing I did NOT do is the fuel flow (for no apparent reason I think).

I have a JPI830 in a 182-S with shared sensors with the original Cessna gauges for oil/cht/egt. As @flyingron mentions, the fuel flow is a separate sensor per JPI installation instructions.

 

[Silvaire]

You can hook it up that way but calling it "redundant" would be a bit insincere.

 

[flyingron]

You can hook it up that way but calling it "redundant" would be a bit insincere.

Yah.... convenience is more of an issue. The MVP sits over on the right side of the panel. The JPI is where the #2 nav used to be (have an HSI now for #1). There are a few things that are redundant between the two. The JPI has its own RPM pickup on one of my mags where as the MVP50 uses connections to both P leads. The MVP also has its own manifold pressure sender (though it's in the same T fitting as the one for the JPI.

I was going to yank the JPI but the mechanic says "why not both." Couldn't come up with a reason why not.

 

[Chip Sylverne]

While on the subject, does anyone have the p/n of the three position toggle for the fuel flow display? I don't need the whole harness, just the switch. It's EGT/All/FF, so I assume it's some flavor of small 3P3T switch.

Never mind, found it. C&K7103 spdt

 

[Chip Sylverne]

So, you guys that have made this 9ne sender two guage thing work, how'd you do it? With only the JPI leads connected to the sender, I get an accurate reading. With only the primary guage connected I get accurate readings. With both the JPI and primary connected in parallel, the JPI reads way high.

Did you have to add a diode or something to prevent the JPI from scavenging signal from the primary guage? The sender meets JPI spec, 10 bar/150 psi 10 to 180 ohm.

 

[Darryl Snover]

A problem with analog sensor/sending units feeding multiple gauges is that they are typically resistance based, and adding a second gauge to the circuit changes the resistance, throwing off the gauge readings.

 

[Ed Haywood]

I also have dial gauges and 830. I installed both OP sensors. Was not hard. Run the hose to an AN tee and attach a sensor to each side. Adel clamp each sensor to the firewall.

To me that makes more sense than paralleling one sensor to two gauges and hoping you are getting the right reading. Easier to justify legally too.