EFFECTIVITY BEJ ALL 31-41-00
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AIMS -INPUT/OUTPUT MODULE FUNCTIONAL DESCRIPTION
General
The input/output module (IOM) supplies the interface between the software functions in the AIMS cabinet and external signal sources. The four IOMs supply most of the standard and shared input and output interfaces necessary to operate the CPMs. Some unique input and output interfaces are supplied by the CPM/Comm and the CPM/GG.
The IOM does not monitor or interrogate any data that passes through it. The IOM is only a high-speed data mover.
IOM Hardware
The IOM has these four circuit card assemblies (CCAs):
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Power supply CCA
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Input/output controller/ backplane interface/power monitor (IOC/BIPM) CCA
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ARINC 629/429 CCA
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Analog and discrete/ARINC 629 CCA.
Power Supply CCA
The power supply CCA receives 28v dc from five sources on the power backplane. The power supply CCA supplies power for:
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IOM CCAs
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5v dc transceiver power backplane
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2v dc termination power backplane
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Different I/O interfaces.
I/O Controller/Backplane Interface/Power Monitor CCA
The I/O controller/backplane interface/power monitor (IOC/ BIPM) CCA has:
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One single thread interface
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Two I/O controllers (IOC)
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Two backplane interface/power monitors (BIPM)
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Four transceivers.
The single thread interface receives data from the input and output interfaces and sends the data to the X IOC and the Y IOC. The single thread interface also receives data from the X IOC and sends the data to the input and output interfaces.
The I/O controllers (IOC) control the operation of the different IOM input and output interfaces. The IOCs receive data from the single thread interface and transmit the data to the BIPMs. Each IOC receives data from a BIPM and compares the data with the other IOC. IF the data is the same, the X IOC sends the data to the single thread interface.
The IOC also supplies the BITE for the IOM. The IOC BITE supplies an IOM BITE history log and an IOM fault history log. The IOC communicates with the four core processing modules to supply IOM BITE data. The functions in the CPMs use the BITE data to check for I/O interface faults.
EFFECTIVITY BEJ ALL 31-41-00
Page 80
D633W101-BEJ Sep 05/2002
AIMS -INPUT/OUTPUT MODULE FUNCTIONAL DESCRIPTION
The IOCs operate in a dual, self-monitoring configuration. The IOCs are identical. The self-monitoring operation allows both IOCs to execute the same instructions on a clock-for-clock basis. The IOCs cross-compare all signals during normal operation. This is called lock-step operation. If the data in each IOC is the same, the X IOC sends the data to the single thread interface. If the data in each IOC is different, the IOCs will not send any more data to the I/O interfaces.
The X BIPM sends data to and receives data from the AX and BX transceivers. The X BIPM also sends data to and receives data from the X IOC. The Y BIPM sends data to and receives data from the AY and BY transceivers. The Y BIPM also sends data to and receives data from the Y IOC.
The BIPM has an intermodule memory (IMM) array for data storage. The IMM array holds the data to be passed from one LRM to another LRM in the cabinet. The IMM array, in combination with the data bus interface, supplies an orderly flow of the data.
For input and output data, the functions in the CPMs need to know what place in the array in the IMM to write to for output data and what place in the array IMM to read from for input data.
The BIPMs also monitor power for the IOM. The BIPMs detect over voltage and under voltage conditions. The BIPMs prevent IOM operation during these conditions. The monitor circuits use a different power source than the rest of the IOM for operation.
The four transceivers supply the interface between the backplane data buses and the BIPM. The four transceivers receive 5v dc from the transceiver power backplane.
ARINC 629 And ARINC 429 CCA
The ARINC 629 and ARINC 429 CCA supplies the interface between the IOC/BIPM CCA and the ARINC 629 and ARINC 429 buses.
The ARINC 629 interface transmits data to and receives data from the ARINC 629 buses. There are two ARINC 629 terminals in this CCA. There is another ARINC 629 terminal in the analog and discrete/ARINC 629 CCA. Each ARINC 629 terminal has one transmit bus and one receive bus.
The ARINC 429 interface transmits data to and receives data from the ARINC 429 buses. An IOM has 27 ARINC 429 receivers and five ARINC 429 transmitters. Each transmitter has a wrap around receiver that monitors the transmitted data. The five wrap around receivers make the total number of receivers equal to 32.
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