Trio Avionics EZ Altitude Control - Manual (Page 11)

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“heartbeat” signal to the supervisory processor for a period of 65 milliseconds, the
supervisory processor will unilaterally cut power to the safety disconnect solenoid and
the trim and servo motor drive circuits. The problem will be reported to the pilot with the
red SERVO FAULT message being displayed on the LCD switch
4.6 Servo / Trim Driver Chip Fault Detection . The integrated circuits used to drive
the servo and trim motors are internally equipped to detect and report to the SMP a
variety of fault conditions including:
• High side (supply side) short to ground (low side)
• Low side short to high side
• Under voltage lockout
• Over temperature shutdown
When any of these faults are detected a red SERVO FAULT message is displayed
4.7 Disconnect Solenoid . The servo contains a solenoid that disconnects the servo
gear train whenever power is removed from the solenoid. Power can be removed under
program control of the Servo Main Processor (SMP), the supervisory processor or
whenever power is interrupted by the Electronics Module. With the gear train
disconnected, the elevators are free to move.
4.8 SMP and Supervisory Processor Watchdog Interrupts . Both the SMP and
Electronics Module processors have built in peripherals for detecting an improper cycle
of the software program. If either of these processors enter this condition a watchdog
interrupt will occur which will automatically reset the processor software. This condition
is conveyed to the pilot with the red SERVO FAULT or the amber SYSTEM TEST
message displayed on the LCD switch.
4.9
EZ-2 / EZ-3 additional safety features. The EZ-2 and EZ-3 systems incorporate
an airspeed sensor which adds the capability to disengage the servo if left on during
takeoff and to sense minimum and maximum airspeeds during all phases of flight.
Section 8 describes these features in more detail
5.0 Installing the Altitude Hold Control Module
The control module is embossed with
lettering indicating TOP and RIGHT (looking
forward). It is important to install this module
in this orientation because the gyro uses this
orientation for pitch recognition. Although the
controller may be installed at any convenient
place and need not be in the panel or close
to it, it must be installed in its proper
orientation. Each face of the module has
tapped holes that allow the long rectangular
mounting plate to be attached to any side of
the unit. This will allow for maximum
flexibility in locating and mounting it in the
aircraft.
A static port is provided to allow the control module to access an accurate pressure source.
While it is possible to operate the altitude hold system with the port open to cockpit pressure,
it is highly recommended that it be connected to the aircraft static pressure system or an
independent static port for most reliable operation.