DOC AIRBUS | AMM A320FOIL PRESSURE INDICATING SYSTEM - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. Oil Pressure Transmitter
Oil Pressure TransmitterA. General
The oil pressure indicating system gives a cockpit in indication of the engine oil system working pressure.
The indication of this pressure comes electrically from an oil pressure transmitter on each engine.
The oil pressure indicating system gives a cockpit in indication of the engine oil system working pressure.
The indication of this pressure comes electrically from an oil pressure transmitter on each engine.
B. Operation
- The oil pressure transmitter is bolted to a bracket on the top left side of the engine fan case.
- The oil pressure transmitter is connected to the engine oil system by two steel tube. One tube connects to the oil supply tube (to the engine and gearbox bearings). The other tube connects to the No. 4 bearing oil scavenge tube (to the oil scavenge pump).
- Power supply : 28VDC from busbar 101PP (202PP).
- Pressure range : 0 to 400 psid.
- Output voltage : 0.7VDC to 9.1VDC varying lineearly with pressure from 0 to 400 psid.
- Accuracy : plus or minus 1%, for 0 to 400 psid.
C. Operation
The 28VDC supply goes through the electromagnetic interference (EMI) filter to the DC/DC converter which changes the voltage to 15VDC. This decreased voltage goes to the strain gauge and amplifier regulator. In the strain gauge, the voltage causes an excitation of the circuit.
Each diaphragm moves by oil pressure from the inlet port. As the diaphragm moves it changes the condition of the attached strain gauge.
This causes a change in the associated excitation voltage. Thus the voltage is in proportion to the oil pressure at the diaphragm.
The excitation voltage goes from the strain gauge to the amplifier regulator. The amplifier increases the voltage to between 0 and 9VDC (changes as the oil pressure changes). This is the output signal voltage which goes through the EMI filter to the cockpit.
The signal voltage of 0 to 9VDC gives a pressure range of between 0 and 400 psi (2720 kPa).
The 28VDC supply goes through the electromagnetic interference (EMI) filter to the DC/DC converter which changes the voltage to 15VDC. This decreased voltage goes to the strain gauge and amplifier regulator. In the strain gauge, the voltage causes an excitation of the circuit.
Each diaphragm moves by oil pressure from the inlet port. As the diaphragm moves it changes the condition of the attached strain gauge.
This causes a change in the associated excitation voltage. Thus the voltage is in proportion to the oil pressure at the diaphragm.
The excitation voltage goes from the strain gauge to the amplifier regulator. The amplifier increases the voltage to between 0 and 9VDC (changes as the oil pressure changes). This is the output signal voltage which goes through the EMI filter to the cockpit.
The signal voltage of 0 to 9VDC gives a pressure range of between 0 and 400 psi (2720 kPa).
2. Oil Pressure Indicating
- The analog signal from the oil pressure transmitter is sent to the SDAC1, SDAC2 and the EIU which transforms the analog signal into a digital signal.
- The digital signal is then transmitted to the ECAM through the FWCs and the DMC.
- The order of priority has been defined as follows:
SDAC1
SDAC2
EIU. - Scale : the oil pressure indication is graduated from 0 to 400 psi on the ECAM display unit.