ICU: The Instrument Control Unit

The Instrument Control Unit (ICU)

The Instrument Control Unit or ICU is the interface between the spacecraft and the EPD sensors. All EPD sensors are connected to the ICU, which provides them a telecommand and telemetry communication link, time synchronization, processing and power.
The ICU is composed of the Common Data Processing Unit (CDPU) and the Low Voltage Power Supply (LVPS), operating in a cold redundant configuration. Therefore the ICU contains four electronic boards, two for the CDPU (nominal+redundant) and two for the LVPS (nominal+redundant). The LVPS provides power to the CDPU and the sensors.
The ICU boards are packaged in a single box in order to reduce mass and to simplify harnessing and interfaces. This box is mounted inside the spacecraft body.

Sensors have also an interface to receive a pulse per second from the ICU. The pulse per second is generated synchronously with the reception of the SpaceWire time-code that the spacecraft transmits periodically. Sensors, as a response to this pulse, provide synchronized data to the ICU with a 1-second period, except SIS that sends data with a 3-second period.
The ICU shares information with MAG, RPW and SWA Solar Orbiter instruments to allow synchronized high data rate burst-mode operations following the on-board identification of predefined triggering events in the EPD data.