1. SOIS architecture to handle RIUs
F. Torelli (ESA) & G. Rakow (NASA) 15/04/2013

2. Outline Remote Interface Unit (RIU) definition Tunnelling RIU and SOIS
Smart RIU and SOIS
RIUs and SOIS EDS
Summary
The presentation summarises the tech note “Aggregated devices in SOIS and SOIS EDS” distributed to the SOIS WG mailing list on 28/11/2012

3. Remote Interface Unit (RIU) definition

4. Remote Interface Unit 1/2
Also known as Remote Terminal Unit
Connects devices to the Processor Module (PM) where flight SW (FSW) runs
Data concentrator
Physical aggregation
Interfaces to very simple sensors/actuators
Interfaces to smart devices
Handles point-to-point links
Handles sensor buses
Sensor bus
DEVA
Point-to-point link
DEV1
DEVB
DEV2
DEVC
Processor Module
FSW
RIU
I/F Logic
System bus/subnetwork

5. Remote Interface Unit 2/2
Tunnelling RIU:
PM manages each device separately
PM is aware of the access protocol and data formats of each device
RIU is just a multiplexer/demultiplexer
Smart RIU:
RIU autonomously access the devices
RIU is aware of access protocol and data formats of each device
PM is only aware of the access protocol and data formats of the RIU
DEVA
DEVA
DEV1
DEVB
DEV1
DEVB
DEV2
DEVC
DEV2
DEVC
RIU complexity
RIU
Cmd & Acq Logic
RIU
Mux/Demux

6. Tunnelling RIU and SOIS

7. Tunnelling RIU in SOIS 1/2
Device access protocol is managed at DAS level in the PM
The “simple” RIU Mux/Demux protocol is managed at DAS level in the PM
System bus communication between PM and RIU is managed at subnetwork level

8. Tunnelling RIU in SOIS 2/2
Possible mux/demux mechanisms:
Commands/data encapsulation via Packet Service
Time separated commands via Packet or Memory Access Service
Packet exchanged at the subnetwork service interface
Cmd/Data consumed/produced by Dev X
RIU Channel X Selector
Dev X Header
Dev X Command/Data
Packet exchanged betwen RIU and Dev X
RIU Channel X Selection
Dev X Command/Data
RIU Channel Y Selection
Dev Y Command/Data
Command to RIU
Cmd/Data to/from Dev X
Command to RIU
Cmd/Data to/from Dev Y

9. Smart RIU and SOIS

10. Smart RIU in SOIS 1/2 Device access protocol is managed at RIU level
Device data are accessed via RIU DAS using specific Value Ids
RIU access protocol is managed at DAS level in the PM
System bus communication between PM and RIU is managed at subnetwork level

11. Smart RIU in SOIS 2/2 Possible RIU/device access mechanisms:
Devices Cmd/Data mixed inside RIU Cmd/Data (Packet Service)
Devices Cmd/Data allocated in RIU memory space (Memory Access Service)
Packet passed to the subnetwork service
RIU Header
Dev X Cmd/Data 1
Dev Y Cmd/Data 1
Dev X Cmd/Data 2
Dev X Cmd/Data for Value Id X1
Dev Y Cmd/Data for Value Id Y1
Dev X Cmd/Data for Value Id X2
Dev X Cmd/Data 1 at 0x10
Value Id X1  MAS rd/wr.req to RIU at addr 0x10
Dev X Cmd/Data 2 at 0x20
Value Id X2  MAS rd/wr.req to RIU at addr 0x20
Dev Y Cmd/Data 1 at 0x28
Value Id Y1  MAS rd/wr.req to RIU at addr 0x28
Dev X Cmd/Data 3 at 0x30
Value Id X3  MAS rd/wr.req to RIU at addr 0x30
Dev Z Cmd/Data 1 at 0x34
Value Id Z1  MAS rd/wr.req to RIU at addr 0x34
Dev Z Cmd/Data 2 at 0x3C
Value Id Z2  MAS read.req to RIU at addr 0x3C

12. RIUs and SOIS EDS

13. Tunnelling RIU and SOIS EDS
RIU + Devices can be described by separate EDS
The DAS of each Device is built from RIU and device specific EDS
Adding a new device to the RIU implies introducing the new Device EDS and a new DAS instance and updating the Device Layout in the RIU EDS
Dev1 EDS
Service I/F
Dev1 Access Prot.
Dev2 EDS
Service I/F
Dev2 Access Prot.
RIU EDS
Service I/F
Mux/Demux Prot.
Devices Layout

14. Smart RIU and SOIS EDS
One EDS describes RIU + Devices as a single equipment
The DAS of the RIU is built from RIU EDS only
Adding a new device to the RIU implies updating the RIU EDS and regenerating the MIB of the RIU DAS to access the new valid Value Ids
RIU EDS
Service I/F
RIU Access Prot.
Devices Layout
RIU EDS is built using devices EDS as input (for data formats)
Credit for the onion diagram: S. Fowell

15. Summary

16. Summary Tunnelling RIU Smart RIU 1 DAS for every device
Each Access Protocol composed by device + RIU access protocol
1 EDS for each device
1 EDS for the RIU
RIU as equipment is described by the collection of the device and RIU EDS
Smart RIU
1 DAS for the RIU as equipment
RIU Access Protocol in charge to extract the device specific data from the RIU data
1 EDS for the RIU as equipment
EDS is built with inputs from device EDS