Dynon Skyview "EMS Failure"

[rwtownson]

Yesterday the Skyview booted with a full screen red cross saying "EMS FAILURE". It would not turn off with the 1 button, and would not turn off with the master. I rebooted the Skyview and it came up apparently as normal.

What I did find is that the RMP indication was fluctuating significantly, and I was getting occasional autopilot warnings. Earlier, on the last few flights I noticed some fluctuation of RPM readings and wondered about what might be causing it.

I recently loaded update 14.2.1.3698 and wonder if there might be a glitch?

I also recently installed the basic knob panel.

The network also contains a number of splitters rather than a hub... This was recommended early in the installation by someone at Dynon but I wonder if there is a maximum number of splits?

Anyone else experienced this?

Ron

 

[dynonsupport]

Perhaps one of the connectors in the path to the SV-EMS-220 is making intermittent contact?

You didn't state what engine you have, and the method of getting RPM (tachometer) info varies by engine type. As soon as we know what type of engine you have we can provide some troubleshooting.

Yesterday the Skyview booted with a full screen red cross saying "EMS FAILURE". It would not turn off with the 1 button, and would not turn off with the master. I rebooted the Skyview and it came up apparently as normal.

What I did find is that the RMP indication was fluctuating significantly, and I was getting occasional autopilot warnings. Earlier, on the last few flights I noticed some fluctuation of RPM readings and wondered about what might be causing it.

I recently loaded update 14.2.1.3698 and wonder if there might be a glitch?

I also recently installed the basic knob panel.

The network also contains a number of splitters rather than a hub...  This was recommended early in the installation by someone at Dynon but I wonder if there is a maximum number of splits?

Anyone else experienced this?

Ron

 

[rwtownson]

I have an Aerosport o-375 equipped with P-Mags which take the tach signal off terminal 6, not the p-lead.

I do not recall putting a resistor in this circuit, although I know it is recommended for magnetos.

'Is a resistor necessary for P-Mags and what value?

Regards

Ron

 

[dynonsupport]

If the RPM / Tachometer display is not stable, then the resistor is required.

It's necessary to experiment with the value of the resistor; the installation manual recommends increasing the value of the resistance in increments of approximately 30 K ohms until the RPM / Tachometer display is stable. Some installations require as much as 150 K ohms resistance. More is not better - too much resistance installed may attenuate the RPM / Tachometer signal below the minimum voltage value necessary to display on the EMS unit.

I have an Aerosport o-375 equipped with P-Mags which take the tach signal off terminal 6, not the p-lead.

I do not recall putting a resistor in this circuit, although I know it is recommended for magnetos. 

'Is a resistor necessary for P-Mags and what value?

Regards

Ron

 

[jakej]

Ron,
FWIW - there is something else going on with your system, probably a wiring issue IMO. There is absolutely no need to add resistors to the P-Mag tach outputs from my experience with having installed many of them.

 

[Pobb]

Ron,
Do you have the 5V zener diode installed between terminals 1 and 6 as per the PMag manual? I have dual PMags with this diode installed and the RPM reading is rock steady.

 

[rwtownson]

I'll double check for the diode...

What's strange is that the RPM readout was rock steady for 170 hrs, then started to jump around?

Makes me think something has changed, just a matter of figuring out what...

 

[preid]

I'll double check for the diode...

What's strange is that the RPM readout was rock steady for 170 hrs, then started to jump around?

Makes me think something has changed, just a matter of figuring out what...

What is even more strange is that I noticed the exact same thing. I was rock solid for 300+ hrs and noticed the unstable readings above 2550rpm a few months ago, I never had this issue before. Not sure why I would need to increase the resistor now when previously it was working flawlessly.
Below 2500RPM is steady.

 

[mrdaud]

Just a quick note that may not apply here, but spent a great deal of time and head scratching working with the P-Mag folks on the same RPM issue.  Finally was diagnosed as P-Mag connector becoming just a bit loose and indicating erratic RPM when engine was creating power vibrations.  Also had the individual wire clamp screws getting loose.  A bit of light Loctite on connector screws and wire clamp screws fixed the problem.  Simple problem, but sometimes hard to diagnose.  Easy to check the connector and eliminate that as a issue before moving on to more serious causes.