Payload Module electrical power, distribution, control and harness

The following elements are involved:

• Power Distribution Unit (PDU)
• Power Control Unit (PCU)
• Thermal Control Unit (TCU)
• PLM Interpanel and Panel Harnesses

The Power Distribution Unit (PDU) uses power from the Service Module (SVM) to supply unregulated power (22 – 37.5 V) to all PLM equipment and European instruments. To provide switching and protection functions, the PDU uses Latch Current Limiters (LCL). The PDU also supplies power for the motor driven deployment of the Advanced Scatterometer (ASCAT) instrument, Low Resolution Picture Transmission (LRPT) and Combined Receive Antenna (CRA) antennas.

The Power Control Unit (PCU) provides regulated power to the National Oceanic and Atmospheric Administration (NOAA) instruments at 28 V.

A Thermal Control Unit (TCU) is dedicated to supplying unregulated power to the heater mats.

Various types of harness

• panel harness located on each structure panel
• inter-panel harness connecting panels to panels and external elements
• instrument harness connecting the various elements within an instrument

Connector brackets on the panels make it easy to attach the harnesses and re-assemble the PLM elements after integration and testing. Interface connectors are used for harnesses that run from the inside to the outside of the PLM. For power and signal harnesses, purpose-built clamp shells are used.