DOC AIRBUS | AMM A320FANALYZERS - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
The EVMU located in the electronics bay provides the following functions by means of accelerometer and tachometer signals and ARINC 429 lines.
** ON A/C NOT FOR ALL The EVMU located in the electronics bay provides the following functions by means of accelerometer and tachometer signals and ARINC 429 lines.
- To give data on the unbalance conditions of each rotor of each engine (with narrow-band tracking filters) and to transmit them for display in the cockpit with advisory levels based on fixed maximun limits and in some conditions on initial levels.
- To give data to rebalance the low-pressure rotor.
- To give broadband filtered data with threshold indications for each engine for maintenance purposes.
- To give automatically or upon request a frequency analysis for maintenance.
- To communicate with the CFDS for maintenance.
2. Engine Vibration Transducer
A. General
The system monitors engine vibration for engine 1 and engine 2. Monitoring is performed by a vibration transducer on each engine fan case. This produces an electrical signal in proportion to the vibration detected and sends it to the cockpit. Two channels come from each engine.
The system monitors engine vibration for engine 1 and engine 2. Monitoring is performed by a vibration transducer on each engine fan case. This produces an electrical signal in proportion to the vibration detected and sends it to the cockpit. Two channels come from each engine.
B. Description
Each vibration transducer is installed in the fan case at the top left side of the engine. It is attached whith bolts and is installed on a mounting plate.
The vibration transducer is made up of two natural crystal assemblies in a steel case. Each crystal assembly is mechanically and electrically separated from the other. An electric cable is connected to each crystal assembly and goes through the housing to a connector on the engine. From there, the signals are transmitted via short screened link leads to the pylon interface connector.
Three fixing bolts secure the transducer to the engine.
Each bolt passes through a hole in the unit and a hole in the mounting plate and screws into a threaded insert in the end of the strut. The mounting plate is sealed to the fan case by an O-ring.
Each vibration transducer is installed in the fan case at the top left side of the engine. It is attached whith bolts and is installed on a mounting plate.
Vibration Transducer and Cable AssemblyThe vibration transducer is made up of two natural crystal assemblies in a steel case. Each crystal assembly is mechanically and electrically separated from the other. An electric cable is connected to each crystal assembly and goes through the housing to a connector on the engine. From there, the signals are transmitted via short screened link leads to the pylon interface connector.
Three fixing bolts secure the transducer to the engine.
Each bolt passes through a hole in the unit and a hole in the mounting plate and screws into a threaded insert in the end of the strut. The mounting plate is sealed to the fan case by an O-ring.
C. Operation
(1) The material in the crystal assembly changes and produces voltage signals when it is vibrated.
(2) The ouput data for the transducer is:
- Charge sensivity 50 PC/g
- Acceleration range 0.01g to 200g. Peak (operating).
- Plus or minus 3% (MAX) of sensitivity at 120Hz over the range 10 to 500Hz.
3. Engine Vibration Monitoring Unit (EVMU)
A. General
The Engine Vibration Monitoring Unit (EVMU) is located on the avionics compartment shelf 86VU.
The EVMU receives analog signals from:
The EVMU sends signals through the digital ARINC 429 data bus to:
The Engine Vibration Monitoring Unit (EVMU) is located on the avionics compartment shelf 86VU.
The EVMU receives analog signals from:
- the 4 engine accelerometers 2 per engine (A and B).
- the N1 speed sensor (TRIM balance probe signal) and the N2 speed sensors of each engine.
The EVMU sends signals through the digital ARINC 429 data bus to:
- the SDAC1 and 2 for cockpit indication
- the CFDIU
- the DMU
- the printer (if installed) for maintenance purposes.
B. Description
The signal conditioner is composed of:
The signal conditioner is composed of:
- 2 channel modules
- 1 balancing module
- 1 data processing module
- 1 power supply module.
(1) Channel modules
Each channel module processes the signals from the two engine accelerometers and from the two speed signals N1 and N2 : this enables the extraction from the overall vibration signal of a component due to rotor first order unbalance.
Only one accelerometer is used at a time (A or B).
The same accelerometer is not used for two successive flights. The changeover occurs at power-up or on special request (MCDU) on the ground. The changeover is only possible through MCDU manual input.
The N1 and N2 signals are used to:
Each channel module processes the signals from the two engine accelerometers and from the two speed signals N1 and N2 : this enables the extraction from the overall vibration signal of a component due to rotor first order unbalance.
Only one accelerometer is used at a time (A or B).
The same accelerometer is not used for two successive flights. The changeover occurs at power-up or on special request (MCDU) on the ground. The changeover is only possible through MCDU manual input.
The N1 and N2 signals are used to:
- drive the tracking filters, and
- slave their center frequencies at the shaft rotational speed.
(2) Balancing module
The balancing module receives:
The balancing module receives:
- the accelerometer signal
- the N1 signal including the 1/REV synchronisation pulse.
(3) Data processing module
This module manages, under program control, the whole signal conditioner operation.
The data processing module:
This module manages, under program control, the whole signal conditioner operation.
The data processing module:
- receives the necessary inputs from the CFDS
- provides outputs to the aircraft corresponding to the selected mode (the outputs depend on the aircraft status).
- the normal mode
- the MENU mode, used on the ground for maintenance purposes (Ref. paragraph Operation).
(4) Power supply module
The power supply module receives the 115VAC/400Hz power. It provides the other modules with the necessary voltages.
The power supply module receives the 115VAC/400Hz power. It provides the other modules with the necessary voltages.
C. Power Supply
The EVMU is supplied with 115V/400Hz by the busbar 101XPA, through the circuit breaker 1EV.
The maximum power consumption is less than 30VA.
The EVMU is not affected by power loss up to 5 ms. For a power interrupt between 5 ms and 200 ms the equipment does not supply any inadvertent indication. It returns to normal operation 200 ms after power return. For longer power loss, vibration data calculated with analog filters can be affected during 10 s. In this case the data transmitted can be lower than real data.
The EVMU is supplied with 115V/400Hz by the busbar 101XPA, through the circuit breaker 1EV.
The maximum power consumption is less than 30VA.
The EVMU is not affected by power loss up to 5 ms. For a power interrupt between 5 ms and 200 ms the equipment does not supply any inadvertent indication. It returns to normal operation 200 ms after power return. For longer power loss, vibration data calculated with analog filters can be affected during 10 s. In this case the data transmitted can be lower than real data.
D. Operation
The EVMU provides the following functions:
The EVMU provides the following functions:
(1) Actual vibration level
Measurement of the actual vibration velocity corresponding to acceleration signals filtered with a narrow-band filter slaved to the rotor speeds.
As normal vibration depends on rotor speed, an absolute actual level cannot give a correct vibration indication. So for each speed, the EVMU processes the actual value/max value ratio. This ratio is multiplied by 10 and is available on the EVMU output for display.
- N1 vibrations are measured as a displacement in mils (1/1000 of an inch), while N2 vibrations are measured as a speed in ips (inch per second). N1 phase angle is also measured in degrees for balancing purposes.
- MAX N1 narrow band vib selection and normalization for display: the display between 0 and 10 units depicts a vibration between 0 and 3 ips (linear).
- MAX N2 narrow band vib selection and normalization for display. The display between 0 and 10 units depicts a vibration between 0 and 3 ips (linear).
Measurement of the actual vibration velocity corresponding to acceleration signals filtered with a narrow-band filter slaved to the rotor speeds.
As normal vibration depends on rotor speed, an absolute actual level cannot give a correct vibration indication. So for each speed, the EVMU processes the actual value/max value ratio. This ratio is multiplied by 10 and is available on the EVMU output for display.
- N1 vibrations are measured as a displacement in mils (1/1000 of an inch), while N2 vibrations are measured as a speed in ips (inch per second). N1 phase angle is also measured in degrees for balancing purposes.
- MAX N1 narrow band vib selection and normalization for display: the display between 0 and 10 units depicts a vibration between 0 and 3 ips (linear).
- MAX N2 narrow band vib selection and normalization for display. The display between 0 and 10 units depicts a vibration between 0 and 3 ips (linear).
(2) Measurement of the unbalance data
The EVMU measures the position and the amplitude of the rotor unbalance of each engine. It provides this information, when available, to the output bus.
The EVMU measures the position and the amplitude of the rotor unbalance of each engine. It provides this information, when available, to the output bus.
(3) Computation of the advisory level
Limit 1 = Max value - X where:
Limit 1 = Max value - X where:
- Max value is the maximum vibration levels which can occur on the engine. These values depend on the rotor speeds (unit: inch/s)
- X is the margin to the Max value = 1.5 inch/s.
The limit 1 value = the advisory value.
At the limit 1 value, the ECAM VIB pulses.
(4) Frequency analysis
The EVMU can perform a frequency analysis if requested from the Multipurpose Control and Display Unit (MCDU) on the ground or automatically from broadband monitoring when threshold level is exceeded . The EVMU makes the analysis at a selected N1 or N2 speed and uses any valid accelerometer (A or B). The maximum frequency analysis is 500 Hz and the frequency increment between adjacent spectral lines is 4 Hz. On the printer it shown in semi-graphic form.
The EVMU can perform a frequency analysis if requested from the Multipurpose Control and Display Unit (MCDU) on the ground or automatically from broadband monitoring when threshold level is exceeded . The EVMU makes the analysis at a selected N1 or N2 speed and uses any valid accelerometer (A or B). The maximum frequency analysis is 500 Hz and the frequency increment between adjacent spectral lines is 4 Hz. On the printer it shown in semi-graphic form.
(5) Storage of unbalance data
If requested, the system can store the balancing data during the cruise phase when stabilized conditions are reached (the actual N1 speed does not fluctuate more than plus or minus 2% during at least 30 seconds). For every stored measurement the stabilized conditions shall be met once more again.
This data is available through the SYSTEM REPORT - EVMU - ENGINE BALANCE - FLIGHT DATA.
If requested, the system can store the balancing data during the cruise phase when stabilized conditions are reached (the actual N1 speed does not fluctuate more than plus or minus 2% during at least 30 seconds). For every stored measurement the stabilized conditions shall be met once more again.
This data is available through the SYSTEM REPORT - EVMU - ENGINE BALANCE - FLIGHT DATA.
(6) BITE maintenance and fault information
The equipment contains a BITE system to detect internal and external failure.
Complete description of the BITE system is given in (Ref. AMM D/O 31-30-00-00).
During the execution of the cyclic BITE sequence, the following parts of the EVMU are checked:
The equipment contains a BITE system to detect internal and external failure.
Complete description of the BITE system is given in (Ref. AMM D/O 31-30-00-00).
During the execution of the cyclic BITE sequence, the following parts of the EVMU are checked:
- The non-volatile memory
- The timers
- The analog-to-digital converter
- The ARINC 429 transmitter and receivers
- The tacho generators.
- N1 and N2 NB velocity
- The unbalance data
- N1 and N2 tacho frequencies
- The accelerometer signals.
E. Interfaces
(1) Inputs
The EVMU receives analog signals from:
The EVMU receives analog signals from:
- the 4 engine accelerometers 2 per engine (A and B).
- the N1 speed sensors (trim balance probe signal) and the N2 speed sensor from each engine.
(2) Outputs
The EVMU transmits output signals through an ARINC 429 data bus. The data transmitted on the single low-speed line is in conformity with ARINC 429.
The SDI definition is as follows:
The status matrix definition is as follows:
The data transmitted on the ARINC 429 line is defined in the following tables:
The EVMU transmits output signals through an ARINC 429 data bus. The data transmitted on the single low-speed line is in conformity with ARINC 429.
The SDI definition is as follows:
| ------------------------------------------ |
| ! BITS ! 10 9 ! |
| !-------------------!--------------------! |
| ! Engine 1 ! 0 1 ! |
| ! Engine 2 ! 1 0 ! |
| ------------------------------------------ |
| ------------------------------------------ |
| ! BITS ! 31 30 ! |
| !-------------------!--------------------! |
| ! Failure warning ! 0 0 ! |
| ! Non-computed data ! 0 1 ! |
| ! Test ! 1 0 ! |
| ! Operation ! 1 1 ! |
| ------------------------------------------ |
| ------------------------------------------------------------------------------- |
| ! PARAMETER ! LABEL! UPDATE! BINARY! SIGNIFICANT! OPERATING! UNITS! |
| ! ! ! TIME ! RANGE ! BITS ! RANGE ! ! |
| ! ! ! (ms) ! ! ! MIN ! MAX! ! |
| !-----------------------!------------------------------------------------------ |
| !N1 vibration ! 135 ! 200 ! 12.8 ! 7 ! 0 ! 10! ! |
| !N2 vibration ! 136 ! 200 ! 12.8 ! 7 ! 0 ! 10! ! |
| !Unbalance phase ! 226 ! 500 ! 512 ! 9 ! 0 !+360!degree! |
| !Unbalance displacement ! 227 ! 200 ! 25.6 ! 8 ! 0 ! 25!mils ! |
| !N1 speed ! 346 ! 200 ! 256 ! 14 ! 15 ! 120!% Rpm ! |
| !N2 speed ! 344 ! 200 ! 256 ! 14 ! 15 ! 120!% Rpm ! |
| !Discrete word ! 035 ! 200 ! ! ! ! ! ! |
| !Maintenance word (a) ! 356 ! 200(b)! ! ! ! ! ! |
| ------------------------------------------------------------------------------- |
| EVMU ARINC Output Data Bus |
(a) Label 356 is used for communication with the CFDS. Its definition is in accordance with the CFDS communication (Ref. AMM D/O 31-30-00-00).
(b) 200 ms in normal mode, 30 ms in menu mode.
| ----------------------------------------------------------------- |
| ! ! ! BIT STATUS ! |
| ! BIT No. ! FUNCTION !--------------- ! |
| ! ! ! 1 ! 0 ! |
| !-----------!----------------------------------!-------!--------! |
| ! 1 ! ! ! X ! |
| ! 2 ! ! ! X ! |
| ! 3 ! ! ! X ! |
| ! 4 ! ! X ! ! |
| ! 5 ! Label ! X ! ! |
| ! 6 ! ! X ! ! |
| ! 7 ! ! ! X ! |
| ! 8 ! ! X ! ! |
| ! 9 ! SDI ! ! ! |
| ! 10 ! SDI ! ! ! |
| ! 11 ! N1 vib. above advisory ! Yes ! No ! |
| ! 12 ! N2 vib. above advisory ! Yes ! No ! |
| ! 13 ! Accelerometer B used ! Yes ! No ! |
| ! 15 ! Frequency analysis done (MENU) ! Yes ! No ! |
| ! 16 ! A element accel channel Fault ! Yes ! No ! |
| ! 17 ! B element accel channel Fault ! Yes ! No ! |
| ! 18 ! N1 speed channel Fault ! Yes ! No ! |
| ! 19 ! N2 speed channel Fault ! Yes ! No ! |
| ! 20 ! Unbalance process Fault ! Yes ! No ! |
| ! 21 ! Frequency analysis Fault ! Yes ! No ! |
| ! 22 ! Non-volatile memory Fault ! Yes ! No ! |
| ! 23 ! Broadband above threshold T ! Yes ! No ! |
| ! 24 ! N1 vib above limit 2 ! Yes ! No ! |
| ! 25 ! N2 vib above limit 2 ! Yes ! No ! |
| ! 26 ! Spare ! ! ! |
| ! 27 ! Spare ! ! ! |
| ! 28 ! EVM SYST. CAT II FAULT ! Yes ! No ! |
| ! 29 ! EVMU CAT I FAULT ! Yes ! No ! |
| ! 30 ! SSM ! ! ! |
| ! 31 ! SSM ! ! ! |
| ! 32 ! Parity ! ! ! |
| ----------------------------------------------------------------- |
| EVMU Status Word-Label 035 |
(3) Indicating
The engine vibration indications are displayed in green on the lower ECAM display unit on the engine and cruise pages. The ECAM display unit receives the information through the ARINC 429 data bus via the SDAC 1 and SDAC 2. If the advisory level is reached (limit 1), the indication flashes (0.6 sec bright, 0.3 sec normal). If the indication is not available, the corresponding indication is replaced by 2 amber crosses.
The engine vibration indications are displayed in green on the lower ECAM display unit on the engine and cruise pages. The ECAM display unit receives the information through the ARINC 429 data bus via the SDAC 1 and SDAC 2. If the advisory level is reached (limit 1), the indication flashes (0.6 sec bright, 0.3 sec normal). If the indication is not available, the corresponding indication is replaced by 2 amber crosses.
(4) CFDS interface
The Centralized Fault Data System (CFDS) enables access to the systems.
The CFDS gives maintenance information and initiates tests through the system BITE (Refer to 31-30-00).
When the maintenance personnel needs information on the condition of the EVMU, the CFDS operates in menu mode. The first menu sent to the MCDU is the main menu. The various functions are detailed below:
The Centralized Fault Data System (CFDS) enables access to the systems.
The CFDS gives maintenance information and initiates tests through the system BITE (Refer to 31-30-00).
When the maintenance personnel needs information on the condition of the EVMU, the CFDS operates in menu mode. The first menu sent to the MCDU is the main menu. The various functions are detailed below:
(a) LAST LEG REPORT
The EVMU sends the list of the LRUs which have been detected faulty during the last leg. During the flight the following faults can be detected:
The EVMU sends the list of the LRUs which have been detected faulty during the last leg. During the flight the following faults can be detected:
- EVMU
- N1 SPEED SENSOR, L
- N1 SPEED SENSOR, R
- N2 SPEED SENSOR, L
- N2 SPEED SENSOR, R
(b) PREVIOUS LEGS REPORT
The EVMU sends the list of the LRUs which have been detected faulty during the legs (maximum 62) previous to the last leg. The faults detected are the same as for the last leg report.
The EVMU sends the list of the LRUs which have been detected faulty during the legs (maximum 62) previous to the last leg. The faults detected are the same as for the last leg report.
(c) LRU IDENTIFICATION
The EVMU sends its part number and manufacturer.
The EVMU sends its part number and manufacturer.
(d) GROUND FAILURE
The EVMU sends the list of the LRUs which have been detected faulty during a ground test. Only the last three detected failures are displayed. The following LRUs are tested:
The EVMU sends the list of the LRUs which have been detected faulty during a ground test. Only the last three detected failures are displayed. The following LRUs are tested:
- EVMU
- VIB SENSOR, L
- VIB SENSOR, R
(e) TEST
The test item allows initiation of a complete check of the EVM system.
If no failure has been detected, the message "TEST OK" is displayed.
If any failure has been detected the failed LRU is displayed. Checked LRUs are the ones listed in the "GROUND FAILURES" item.
The test item allows initiation of a complete check of the EVM system.
If no failure has been detected, the message "TEST OK" is displayed.
If any failure has been detected the failed LRU is displayed. Checked LRUs are the ones listed in the "GROUND FAILURES" item.
(f) ACCELEROMETER RECONFIGURATION
This menu allows selection of the accelerometer (A or B) or the auto switch mode alternate to be used for the next flights. The EVMU also indicates which accelerometer is in operation.
This menu allows selection of the accelerometer (A or B) or the auto switch mode alternate to be used for the next flights. The EVMU also indicates which accelerometer is in operation.
(g) ENGINE UNBALANCE
This menu permits for both engine, to command unbalance data storage during next flight and the read out of the stored data. It also permits to effectuate balancing for a selected engine with both accelerometers.
This menu permits for both engine, to command unbalance data storage during next flight and the read out of the stored data. It also permits to effectuate balancing for a selected engine with both accelerometers.
(h) FREQUENCY ANALYSIS
This menu enables a request for a frequency analysis of the acceleration signal. The results of the frequency analysis are sent to the printer.
This menu enables a request for a frequency analysis of the acceleration signal. The results of the frequency analysis are sent to the printer.
(i) SHOP MAINTENANCE
This menu is operational only when the EVMU is in the shop for maintenance. It allows trouble-shooting of the line replaceable unit itself.
This menu is operational only when the EVMU is in the shop for maintenance. It allows trouble-shooting of the line replaceable unit itself.