EZ Series Altitude Control Systems Operation and Installation Manual Trio Avionics Corporation Rev 1.
Notice and Warnings Warning: Any failure to comply with the following warnings can lead to property damage, and serious injury including death. Although Trio Avionics has taken reasonable steps to test its product, the final determination of safe operation lies with you, the installer and pilot. Your workmanship in installing, cabling, and testing the Altitude Hold system in your airplane is critical to safety.
Table of Contents Page 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0 13.0 Notice and Warnings .................................................................................................................... 2 Introduction ................................................................................................................................... 4 General Information......................................................................................................................
EZ Altitude Control System 1.0 Introduction Congratulations on choosing the EZ Altitude Control System. The EZ-1 System is designed to hold a precise altitude of the aircraft. The EZ-2 system has all the features of the EZ-1 system and adds additional safety features, vertical rate selection and vertical speed or airspeed capture capabilities. The EZ-3 system builds on the capabilities of the EZ-1 and EZ-2 systems adding airspeed management modes and altitude preselect and capture features.
with a green ALT HOLD message on the LCD display. (At this time servo activation should be detected by resistance to manual yoke or stick movement forward or backward) To disconnect the EZ altitude control system servo activation either the REMOTE AUTOPILOT DISCONNECT switch or the LCD SWITCH may be momentarily pressed. During normal operation in the altitude hold mode the ENCODER knob may be used to dial in very fine corrections to the engaged altitude.
The system will then immediately release the elevators from servo control and enter the READY mode. Turning off power to the unit will also release the servo. 3.2.1 Fine Adjustments to Altitude - While flying with the ALT HOLD engaged, the ENCODER knob may be used to dial in very fine corrections to the engaged altitude.
If the pilot wishes to re-trim the aircraft without disconnecting the ALT HOLD, trim adjustments should be made in small increments. When each adjustment is made, the pilot should wait for approximately 30 seconds to allow the system to sense the change. If the “Trim” message remains, continue further adjustments until the ALT HOLD message returns. 3.3 Pilot Command Steering (PCS) Mode In addition to the servo disconnect function, the REMOTE DISCONNECT switch can be used to “fly to” another altitude.
The TRIM SPEED setting is only available if the AUTO TRIM option is installed. The TRIM SPEED setting allows the pilot to tailor the speed of the trim correction for the particular airplane and trim drive motor. TRIM SPEED 10 4.
airframe designer’s limitation regarding use of an autopilot system in turbulent conditions. If an EZ altitude control system control problem is suspected, turn off power to the system and contact Trio Avionics for direction before further use. 3.5.5 Servo Clutch Slip The EZ altitude control system incorporates an important special safety feature: a clutch within the servo that can be overridden when actived by moderate manual stick or yoke pressure.
3.5.5 Servo Fault This red message can be due to several factors based on sensors within the servo and will always cause an immediate disconnect and power down of the servo.
“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.
If you have an EZ-2 or EZ-3 altitude hold system, you will also be required to connect the electronics control module to your pitot system. This allows the system to sense airspeed so that it can limit Minimum Airspeed and Maximum Airspeed, allow Climb-on-Airspeed, and enable Pilot Command Steering (PCS) with airspeed control (see section 8). Note that the pitot port is closest to the 25 pin DIN connector. 5.
6.0 Servo Installation Setup The servo unit incorporates important safety features: • The internal gears are pulled into the engaged position by an electric solenoid. When the gears are not engaged, the output crank arm rotates freely and the elevator controls can be operated normally without friction. When the servo is engaged, the solenoid pulls the gears into place so the servo has control of the elevators. Disengaging the servo allows free movement of the elevator controls.
checking that the required range of elevator movement is available within the limits of the servo travel range, and that no “over center” condition can exist. The servo crank arm uses a pushrod terminated by rod end bearings to link the servo arm to the aircraft elevator control system. The pushrod provided in the installation kit should be trimmed to the correct length for your particular installation.
6.3 Selecting a Site for the Servo For most aircraft, it’s relatively easy to find a suitable site for locating the crank arm servo. The length of the pushrod and, to some extent, the angle it makes with the driven element are user selectable. The rod end bearing allows some misalignment, usually about 8 degrees, between the servo pushrod and the plane of rotation of the crank arm. This limit on angular displacement often determines the minimum pushrod length.
The control movements are so small that it takes very little slop in the system to make the airplane not track properly. It will simplify installation adjustments if there is enough overhead clearance to allow removal and replacement of the servo lid with the servo remaining in place (for instance, you will possibly want to adjust the slip clutch). The servo lid is secured by two screws on the top of the servo. 6.
The servo Torque Control nut (the adjustment nut inside the servo on the output shaft) sets the override force - the force you will feel at the stick when the servo clutch begins to slip. Engage the servo by pressing the LCD switch. You should hear the solenoid operate inside the servo housing and the servo crank arm should become firmly held in place by the gear train. Then push the control stick hard enough to override the servo.
Repeat step “a” above and verify correct elevator directional control is achieved. Pressing the LCD switch will advance to the TRIM DIRECTION screen if the system has the AUTO TRIM option installed 6.6.2 Setting the Trim Motor Direction – This procedure is only available on models equipped with the auto-trim option. When in this mode, the LCD message will be amber and read “TRIM DIR NORM” or “TRIM DIR REV”.
c. Execute a turn at a bank angle of approximately 15 degrees. If the altitude sags more than 30 feet after entering the turn the system gain needs to be increased. Perform step d. d. Increase the SYSTEM GAIN by 5 units, then repeat step c. NOTE: This gain setting is for smooth air tracking. If you enter turbulent conditions and the altitude excursions are more than what you will accept, you may increase the gain (clockwise rotation) to limit the altitude excursion.
8.0 The EZ-2 / EZ-3 ALTITUDE CONTROL SYSTEMS with Climb and Descent capability. Section 8 describes the additional features of the EZ-2 systems. The EZ-2 and EZ-3 altitude control system incorporates all of the features of the EZ-1 while adding several additional capabilities and safety features. • • • • • A major safety feature of the EZ-2 and EZ-3 system is its ability to prevent the system from stalling or over speeding the aircraft.
under autopilot control, the pilot may adjust the rate by simply turning the encoder knob. The aircraft will then respond to that vertical command rate. It must be noted that soon after a climb or descent is initiated, the TRM screen will likely flash a warning that the aircraft is out of trim. If UP the climb or descent will be of significant duration, the pilot must adjust the aircraft trim and throttle settings as required. The trim message will alternate with the normal “VS” message.
the aircraft will begin to climb. The pilot will likely advance the engine power to keep the speed up during the climb. Now let’s assume that the pilot rotates the encoder to command a 2,000 fpm climb. Most aircraft will not be able to achieve such a vertical rate and the aircraft will approach a stall. As the airspeed falls to the Minimum Airspeed Limit, the LCD display will flash red and display “MIN AS LIMIT” and the system will issue a pitch down command to the servo to prevent a stall.
the encoder to enter a 500 fpm climb and press the LCD switch to engage the servo. Once the aircraft is established in the climb, slowly retard the throttle until the airspeed decays to the minimum airspeed that you have previously set. The LCD display should flash red and indicate “MIN AS LIMIT”. Check to be sure that the system lowers the nose of the aircraft so that the airspeed settles out at the minimum airspeed that you have set.
pressing the LCD switch) will store this function in nonvolatile memory. The PCS mode will now climb and descend on airspeed rather than vertical speed. Therefore, a pilot may wish to climb at, say, 120 knots for best engine cooling. This may now be done by pressing and holding the remote disconnect switch and placing the aircraft into a climb that indicates an airspeed of 120 knots. Releasing the button will reengage the servo and continue the climb at that airspeed.
9.0 The EZ-3 ALTITUDE CONTROL SYSTEM with Altitude Pre-select Section 9 describes the additional features of the EZ-3 system. The EZ-3 altitude control system incorporates all of the features of the EZ-2 while adding altitude pre-select and other capabilities. • The pilot may pre-select a destination altitude. When engaged, the system will command the aircraft to climb or descend to the selected altitude.
Once the setting is correct, press the LCD switch to put the system in the READY mode. The system is now calibrated and ready to use. If the system is cycled in flight, it will sense airspeed and the message will read as shown to the right (now indicating altitude instead of elevation). The aircraft should be level (not climbing or descending) so that the aircraft altimeter needles are not moving. The initial altitude will be close to that shown by the aircraft altimeter.
1. From the READY mode, repeatedly pressing the encoder will toggle through the various mode screens as shown below (solid arrows). These screens will appear as amber (waiting) unless the LCD switch is pressed when they will change to green (working). A red screen either disconnects the EZ-3 or, in the case of max airspeed, indicates that significant safety measures have been implemented. In the READY mode, press the LCD switch to engage ALT HOLD. Press ALT HOLD to go back to READY. 2.
9.1.3 Enter Vertical Speed (VS) To enter a vertical speed, press the encoder switch to advance to the VS MODE screen. It will initially indicate a “0” vertical speed. To initiate a climb or descent, just dial in the climb or descent rate and press the LCD switch. The aircraft will then begin to climb or descend at the vertical speed that was entered. The mode of operation here is the same as it is in the EZ-2 system.
10.0 Altitude Hold Wiring Diagram Altitude Hold Wiring Diagram Note: the +12VDC input (pins 12 and 22) should be sourced through a circuit breaker with a rating of 3 to 5 amps.
11. 0 Automatic Trim The automatic trim is an optional feature that allows the altitude hold system to automatically adjust the aircraft electric trim motor to keep the elevator forces balanced. The pilot may then change engine power settings and command climbs and descents without the necessity to manually re-trim the aircraft. The trim servo/motor is not provided by Trio as a part of the automatic trim system. It is usually specified or provided by the aircraft builder / kit provider.
12.0 Glossary of Terms Brightness Contrast EEPROM Firmware G-Force Gain LED LCD PCS Processor Interrupt Rotary Encoder Servo Servo Clutch Servo Deadband SMP Solenoid RS232 13.
