The PLATO-F Instrument Module

The PLATO-F Instrument Module was designed and built by the University of New South Wales during 2010. The Instrument Module has the same dimensions as a standard 10 foot shipping container, allowing it to be coupled to the Engine Module and shipped as an ISO standard 20 foot container.

The Instrument Module contains the core control, communication, computing and power conversion electronics for PLATO-F. The module is designed as a stand-alone unit with a 120VDC bus, able to be powered from solar panels or an external 120VDC power source (normally from the Engine Module). A bank of LiFePO4 cells provides 20 kWhr of uninterrupted power to the instruments, and allows for multiple restart attempts and heating of the Engine Module if needed. All the PLATO-F equipment and experiments are standardised to operate from either 24VDC or 110VAC at 60Hz.

The Instrument Module's primary purpose is to provide all the supporting infrastructure for PLATO-F's instrument suite. Each instrument is provided with its own customisable power, communication, and thermal control.

PLATO-F ready for loading on the Shirase The Instrument Module (yellow), and the Engine Module (green) on the upper deck of the Shirase icebreaker, ready for its journey to Antarctica—26 November 2010. The modules are composed of fibreglass panels bolted to a stainless steel skeleton. The panels encapsulate a 20cm thickness of polyurethane for insulation (credit: Michael Ashley)
battery packTwo-thirds of the 20 kWhr LiFePO4 battery pack in the Instrument Module. The batteries are in a heated, insulated, box (credit: Michael Ashley)

PLATO-F is designed to run unattended for periods of up to two years. To achieve this level of autonomy, two redundant Linux-based supervisor computers, each with their own management electronics and Iridium satellite modem, provide multiple paths of communication with each other and the outside world. The supervisor computers monitor and control the PLATO-F power distribution, thermal, and engine management subsystems via CAN (control area network) bus, and are able to gracefully handle various failure scenarios. High-bandwidth communication between the instruments and the supervisor computers is provided via Ethernet. In addition, an Iridium OpenPort system provides 128 kbps internet connectivity to the outside world.

Bulk data are stored in cold-verified flash memory or 2.5-inch SATA hard disks for later retrieval by the JARE traverses. The PLATO-F control system monitors around 140 analog channels, multiple video sources, and distributes electrical power and heating to 96 current-monitored channels via a priority-based allocation algorithm.

The module is extremely well insulated with 200mm thick polyurethane foam. The internal temperature is computer controlled using fans that can bring in cold air from outside. Additional fans can be switched on to prevent large temperature gradients due to stratification from occurring. Heaters are placed in key points in the module and the battery compartment, and several software thermal control loops ensure that cold-sensitive items such as the battery bank and cold-sensitive electronics are kept within operating range. The Instrument Module internal temperature is regulated between –20°C and +15°C depending on the time of the year. Perhaps surprisingly, overheating of electronics is potentially an issue on the Antarctic plateau since the efficiency of convective cooling is reduced in the thin air.

The interior of the Instrument ModuleThe interior of the Instrument Module, immediately prior to shipping to Antarctica. The two supervisor computers are in the top section of the left-hand rack. Power supplies are in the right-hand rack. The scientific experiments were installed upon arrival at Dome F. The photographer was standing on the LiFePO4 battery pack. The two Iridium antennas at the lower left were bolted to the floor for shipping, and are now installed on the roof (credit: Michael Ashley)