Communications Bus Data - Lycoming TEO-540-C1A Maintenance Manual

TEO-540-C1A Engine Maintenance Manual

Communications Bus Data

The CAN and RS232 bus provides data that can be displayed on a third-party display unit
compatible with CAN and R232 protocols. Current revisions of CAN and RS232 Specifications can
be obtained by contacting Lycoming Engines. These specifications include details, such as units,
data format, lists annunciator light colors and functions, and the wiring pin out and schematic from
the system. Hardwired annunciator lights are required to display warnings and cautions.
Not all data transmitted on the communications buses are useful to the pilot, but may be used to
record or view for maintenance or development. At the discretion of the aircraft manufacturer the
following data from directly measured parameters and discrete input system states are considered
valid for display to the pilot:
• Engine Oil Temperature (EOT)
• Engine Oil Pressure (EOP)
• Engine Speed (rpm)
• Manifold Pressure (MAP)
• Manifold Air Temperature (MAT)
• Deck Air Pressure (Deck P)
• Deck Air Temperature (Deck T)
• Fuel Rail Pressure (Fuel P)
• Fuel Rail Temperature (Fuel T)
• Fuel Pump Pressure (Fuel PP)
• Fuel Filter Pressure Drop (FFPD)
• Compressor Inlet Pressure (CIP)
• All EGT values (EGTn)
• All CHT values (CHTn)
• Turbine Inlet Temperatures (TITn)
Data from calculated or indirect control parameters may be useful information during maintenance
or development, but do not have sufficient accuracy or usefulness to display to the pilot. Lycoming
considers the following parameters as reference only:
• Estimated Percent Power
• Air Mass Flow Rate
• Estimated Fuel Mass Flow Rate
• Estimated Fuel Volume Flow Rate
• All Validity Flags
© 2018 Avco Corporation. All Rights Reserved
November 2018
• Requested Power or Throttle Position (POR)
• Lamp Status
• ECU Supply Volts
• ECU Voltage Source
• Active Fault Count
• TLO Time Remaining
• Trip Time
• Engine Hours (Tach Time)
• Time Before Overhaul hours
• Software and Calibration Cyclic
Redundancy Check (CRC)
• All Pre-Flight Test Related Messages
• Operating Mode
• Fault Messages
Appendix B
Page 367