Dynon Avionics SkyView System Installation Guide - Manual (Page 150)

SV-EMS-220/221 Installation and Configuration
7-38 SkyView System Installation Guide - Revision S
Depending upon existing equipment and engine type, you have a few options for connecting
the tachometer inputs on the SV-EMS-220/221. Table 36 revisits the SV-EMS-220/221 pins that
are compatible with RPM sources.
Pin Wire Color Function
32 White/Green Standard RPM Input Left (10+ volts)
33 White/Blue Standard RPM Input Right (10+ volts)
34 Blue Low Voltage RPM Input Left (< 12 volts)
35 Green Low Voltage RPM Input Right (< 12 volts)
Table 36 – SV-EMS-220/221 RPM Inputs
See the relevant subsections below for your particular method. You may connect different
types of signals to the two different RPM inputs (e.g., p-lead to Standard RPM Left and a 12 volt
transducer to Standard RPM Right).
SkyView will display RPM from either the RPM Input Left or the RPM Input Right, whichever is
noticed by the SV-EMS-220 first. If the first RPM signal is lost (such as when one ignition source
fails, or during a routine mag check), then SkyView will display RPM from the remaining RPM
signal. If your engine only provides one RPM signal, connect it to one of the two RPM Input Left
pins.
Pin 32 and 34 are both LEFT RPM input. Use one, or the other, but not both.
Pin 33 and 35 are both RIGHT RPM input. Use one, or the other, but not both.
Tachometer transducer
If you have a dedicated tachometer transducer (usually with a 12 volt output), you may simply
connect its output to the Standard RPM Left input on the SV-EMS-220/221. Ensure that you
follow all recommendations given in the manual for your individual tachometer transducer.
P-lead pickoff (Lycoming and Continental)
If you do not have a dedicated tachometer pickoff, you
must follow the instructions below.
Use the two included 30 kΩ resistors (color bands:
orange, black, brown, red, brown; connect in either
direction) to attach left and right P-leads to the standard
RPM Left and RPM Right inputs on the SV-EMS-220/221.
Connect them as shown in Figure 32. It is important to
connect each resistor as close as possible to the spot
where you tap into the P-lead. This minimizes the length of cable carrying high voltage spikes.
Six-cylinder Lycoming engines sometimes need more inline resistance to prevent false readings
by the SV-EMS-220/221. If you supply your own resistors, they need not be exactly 30 kΩ.
Additionally, both 1/4W and 1/2W resistors are acceptable to use.
Figure 32 – Magneto Pick Off