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Steve
Without the resistor, the eleven unwanted pulses that go below zero are also inverted. With the resistor they stay positive and are almost eliminated. You could see if CAS #2 is causing interference by removing the resistor from CAS #1.
Bobby
Sent from my iPad
Bobby,
Not wanting to make any changes to the controller, the resistors were added to the wiring harness at the CAS end. So the path to ground was unchanged. Thanks for the suggestion.
Steve
From: Rotary motors in aircraft [flyrotary@lancaironline.net] on behalf of Bobby J. Hughes [bhughes@qnsi.net]
Sent: Tuesday, November 06, 2012 6:11 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Renesis CAS & EC-2 upgrade?
Floating ground?
Sent from my iPad
A follow-up on the attempt to use Renesis CAS with an EC2 controller set up for '86 stock Mazda CAS.
There appeared to be a correlation between loosing the rotor 2 controller signals with crossing the staging threshold on startup. This was tested by starting the engine with the throttle open sufficiently that the manifold pressure should not drop to less
than the staging threshold. The result was that the engine still ran only on rotor 1 until RPM reached at least 1400 RPM. It just didn't take as long to reach this RPM as before. This behavior and examination of controller signals recorded during the startup
disproved the appearance of a correlation between loosing rotor 2 controller signals and staging.
1K ohm resistors were then added between each Renesis CAS signal and ground. With these resistors installed, the engine started easily and ran normally at all throttle settings. Since the engine was operated with
this setup for only a few minutes, it is unknown if this is a reliable solution. If it isn't, it is certainly a step in the right direction. Plots of the CAS signals with and without the 1K ohm resistors are attached. The voltage
scales on the two plots are the same, but voltages read from the plots must be multiplied by a factor of 3 to give absolute values in volts. Higher resolution plots of the CAS signals are available on request. Any feedback on
why adding the resistors is effective would be welcome.
RV6A, 1986 13B NA, RD1A, EC2
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